New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
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// Copyright (c) 2018-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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#include "db/db_test_util.h"
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#include "port/stack_trace.h"
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#include "rocksdb/perf_context.h"
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#include "rocksdb/utilities/debug.h"
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#include "table/block_based/block_builder.h"
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#if !defined(ROCKSDB_LITE)
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#include "test_util/sync_point.h"
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#endif
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#include "rocksdb/merge_operator.h"
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2020-07-09 21:33:42 +00:00
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#include "utilities/fault_injection_env.h"
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New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
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#include "utilities/merge_operators.h"
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#include "utilities/merge_operators/sortlist.h"
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#include "utilities/merge_operators/string_append/stringappend2.h"
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2020-02-20 20:07:53 +00:00
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namespace ROCKSDB_NAMESPACE {
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New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
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2021-06-10 19:55:29 +00:00
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namespace {
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class LimitedStringAppendMergeOp : public StringAppendTESTOperator {
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New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
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public:
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2021-06-10 19:55:29 +00:00
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LimitedStringAppendMergeOp(int limit, char delim)
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: StringAppendTESTOperator(delim), limit_(limit) {}
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New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
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2021-06-10 19:55:29 +00:00
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const char* Name() const override {
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return "DBMergeOperatorTest::LimitedStringAppendMergeOp";
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}
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New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
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2021-06-10 19:55:29 +00:00
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bool ShouldMerge(const std::vector<Slice>& operands) const override {
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if (operands.size() > 0 && limit_ > 0 && operands.size() >= limit_) {
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return true;
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New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
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}
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2021-06-10 19:55:29 +00:00
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return false;
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}
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New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
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2021-06-10 19:55:29 +00:00
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private:
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size_t limit_ = 0;
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};
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} // namespace
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New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
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2021-06-10 19:55:29 +00:00
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class DBMergeOperandTest : public DBTestBase {
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public:
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DBMergeOperandTest()
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2021-07-23 15:37:27 +00:00
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: DBTestBase("db_merge_operand_test", /*env_do_fsync=*/true) {}
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2021-06-10 19:55:29 +00:00
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};
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New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
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Fix GetMergeOperands() heap-use-after-free on flushed memtable (#9805)
Summary:
Fixes https://github.com/facebook/rocksdb/issues/9066.
Prior to the fix in this PR, this PR's unit test reported the following error under ASAN:
```
==2175705==ERROR: AddressSanitizer: heap-use-after-free on address 0x61f0000012a5 at pc 0x7f0fc36e76ce bp 0x7ffc103e9ca0 sp 0x7ffc103e9450
READ of size 5 at 0x61f0000012a5 thread T0
#0 0x7f0fc36e76cd in __interceptor_memcpy /home/engshare/third-party2/gcc/9.x/src/gcc-10.x/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:790
https://github.com/facebook/rocksdb/issues/1 0x7f0fc35a207e in std::char_traits<char>::copy(char*, char const*, unsigned long) /home/engshare/third-party2/libgcc/9.x/src/gcc-9.x/x86_64-facebook-linux/libstdc++-v3/include/bits/char_traits.h:365
https://github.com/facebook/rocksdb/issues/2 0x7f0fc35a207e in std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_S_copy(char*, char const*, unsigned long) /home/engshare/third-party2/libgcc/9.x/src/gcc-9.x/x86_64-facebook-linux/libstdc++-v3/include/bits/basic_string.h:351
https://github.com/facebook/rocksdb/issues/3 0x7f0fc35a207e in std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_replace(unsigned long, unsigned long, char const*, unsigned long) /home/engshare/third-party2/libgcc/9.x/src/gcc-9.x/x86_64-facebook-linux/libstdc++-v3/include/bits/basic_string.tcc:440
https://github.com/facebook/rocksdb/issues/4 0x8679ca in std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::assign(char const*, unsigned long) /mnt/gvfs/third-party2/libgcc/4959b39cfbe5965a37c861c4c327fa7c5c759b87/9.x/platform009/9202ce7/include/c++/9.3.0/bits/basic_string.h:1422
https://github.com/facebook/rocksdb/issues/5 0x8679ca in rocksdb::PinnableSlice::PinSelf(rocksdb::Slice const&) include/rocksdb/slice.h:171
https://github.com/facebook/rocksdb/issues/6 0x8679ca in rocksdb::DBImpl::GetImpl(rocksdb::ReadOptions const&, rocksdb::Slice const&, rocksdb::DBImpl::GetImplOptions&) db/db_impl/db_impl.cc:1930
https://github.com/facebook/rocksdb/issues/7 0x547324 in rocksdb::DBImpl::GetMergeOperands(rocksdb::ReadOptions const&, rocksdb::ColumnFamilyHandle*, rocksdb::Slice const&, rocksdb::PinnableSlice*, rocksdb::GetMergeOperandsOptions*, int*) db/db_impl/db_impl.h:203
https://github.com/facebook/rocksdb/issues/8 0x547324 in rocksdb::DBMergeOperandTest_FlushedMergeOperandReadAfterFreeBug_Test::TestBody() db/db_merge_operand_test.cc:117
https://github.com/facebook/rocksdb/issues/9 0x7241da in void testing::internal::HandleSehExceptionsInMethodIfSupported<testing::Test, void>(testing::Test*, void (testing::Test::*)(), char const*) third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3899
https://github.com/facebook/rocksdb/issues/10 0x7241da in void testing::internal::HandleExceptionsInMethodIfSupported<testing::Test, void>(testing::Test*, void (testing::Test::*)(), char const*) third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3935
https://github.com/facebook/rocksdb/issues/11 0x701a47 in testing::Test::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3973
https://github.com/facebook/rocksdb/issues/12 0x702040 in testing::Test::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3965
https://github.com/facebook/rocksdb/issues/13 0x702040 in testing::TestInfo::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:4149
https://github.com/facebook/rocksdb/issues/14 0x7025f7 in testing::TestInfo::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:4124
https://github.com/facebook/rocksdb/issues/15 0x7025f7 in testing::TestCase::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:4267
https://github.com/facebook/rocksdb/issues/16 0x704217 in testing::TestCase::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:4253
https://github.com/facebook/rocksdb/issues/17 0x704217 in testing::internal::UnitTestImpl::RunAllTests() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:6633
https://github.com/facebook/rocksdb/issues/18 0x72505a in bool testing::internal::HandleSehExceptionsInMethodIfSupported<testing::internal::UnitTestImpl, bool>(testing::internal::UnitTestImpl*, bool (testing::internal::UnitTestImpl::*)(), char const*) third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3899
https://github.com/facebook/rocksdb/issues/19 0x72505a in bool testing::internal::HandleExceptionsInMethodIfSupported<testing::internal::UnitTestImpl, bool>(testing::internal::UnitTestImpl*, bool (testing::internal::UnitTestImpl::*)(), char const*) third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3935
https://github.com/facebook/rocksdb/issues/20 0x704aa1 in testing::UnitTest::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:6242
https://github.com/facebook/rocksdb/issues/21 0x4c4aff in RUN_ALL_TESTS() third-party/gtest-1.8.1/fused-src/gtest/gtest.h:22110
https://github.com/facebook/rocksdb/issues/22 0x4c4aff in main db/db_merge_operand_test.cc:404
https://github.com/facebook/rocksdb/issues/23 0x7f0fc3108dc4 in __libc_start_main ../csu/libc-start.c:308
https://github.com/facebook/rocksdb/issues/24 0x5445fd in _start (/data/users/andrewkr/rocksdb/db_merge_operand_test+0x5445fd)
0x61f0000012a5 is located 1061 bytes inside of 3264-byte region [0x61f000000e80,0x61f000001b40)
freed by thread T0 here:
#0 0x7f0fc375b6af in operator delete(void*, unsigned long) /home/engshare/third-party2/gcc/9.x/src/gcc-10.x/libsanitizer/asan/asan_new_delete.cc:177
https://github.com/facebook/rocksdb/issues/1 0x743be8 in rocksdb::SuperVersion::~SuperVersion() db/column_family.cc:432
https://github.com/facebook/rocksdb/issues/2 0x8052aa in rocksdb::DBImpl::CleanupSuperVersion(rocksdb::SuperVersion*) db/db_impl/db_impl.cc:3534
https://github.com/facebook/rocksdb/issues/3 0x8676c2 in rocksdb::DBImpl::ReturnAndCleanupSuperVersion(rocksdb::ColumnFamilyData*, rocksdb::SuperVersion*) db/db_impl/db_impl.cc:3544
https://github.com/facebook/rocksdb/issues/4 0x8676c2 in rocksdb::DBImpl::GetImpl(rocksdb::ReadOptions const&, rocksdb::Slice const&, rocksdb::DBImpl::GetImplOptions&) db/db_impl/db_impl.cc:1911
https://github.com/facebook/rocksdb/issues/5 0x547324 in rocksdb::DBImpl::GetMergeOperands(rocksdb::ReadOptions const&, rocksdb::ColumnFamilyHandle*, rocksdb::Slice const&, rocksdb::PinnableSlice*, rocksdb::GetMergeOperandsOptions*, int*) db/db_impl/db_impl.h:203
https://github.com/facebook/rocksdb/issues/6 0x547324 in rocksdb::DBMergeOperandTest_FlushedMergeOperandReadAfterFreeBug_Test::TestBody() db/db_merge_operand_test.cc:117
https://github.com/facebook/rocksdb/issues/7 0x7241da in void testing::internal::HandleSehExceptionsInMethodIfSupported<testing::Test, void>(testing::Test*, void (testing::Test::*)(), char const*) third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3899
https://github.com/facebook/rocksdb/issues/8 0x7241da in void testing::internal::HandleExceptionsInMethodIfSupported<testing::Test, void>(testing::Test*, void (testing::Test::*)(), char const*) third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3935
https://github.com/facebook/rocksdb/issues/9 0x701a47 in testing::Test::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3973
https://github.com/facebook/rocksdb/issues/10 0x702040 in testing::Test::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3965
https://github.com/facebook/rocksdb/issues/11 0x702040 in testing::TestInfo::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:4149
https://github.com/facebook/rocksdb/issues/12 0x7025f7 in testing::TestInfo::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:4124
https://github.com/facebook/rocksdb/issues/13 0x7025f7 in testing::TestCase::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:4267
https://github.com/facebook/rocksdb/issues/14 0x704217 in testing::TestCase::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:4253
https://github.com/facebook/rocksdb/issues/15 0x704217 in testing::internal::UnitTestImpl::RunAllTests() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:6633
https://github.com/facebook/rocksdb/issues/16 0x72505a in bool testing::internal::HandleSehExceptionsInMethodIfSupported<testing::internal::UnitTestImpl, bool>(testing::internal::UnitTestImpl*, bool (testing::internal::UnitTestImpl::*)(), char const*) third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3899
https://github.com/facebook/rocksdb/issues/17 0x72505a in bool testing::internal::HandleExceptionsInMethodIfSupported<testing::internal::UnitTestImpl, bool>(testing::internal::UnitTestImpl*, bool (testing::internal::UnitTestImpl::*)(), char const*) third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3935
https://github.com/facebook/rocksdb/issues/18 0x704aa1 in testing::UnitTest::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:6242
https://github.com/facebook/rocksdb/issues/19 0x4c4aff in RUN_ALL_TESTS() third-party/gtest-1.8.1/fused-src/gtest/gtest.h:22110
https://github.com/facebook/rocksdb/issues/20 0x4c4aff in main db/db_merge_operand_test.cc:404
https://github.com/facebook/rocksdb/issues/21 0x7f0fc3108dc4 in __libc_start_main ../csu/libc-start.c:308
https://github.com/facebook/rocksdb/issues/22 0x5445fd in _start (/data/users/andrewkr/rocksdb/db_merge_operand_test+0x5445fd)
...
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9805
Test Plan: following the fix in this PR, the new unit test passes
Reviewed By: jay-zhuang
Differential Revision: D35388415
Pulled By: ajkr
fbshipit-source-id: b39c5d002155906c8abc4a3429eca696dbf916d0
2022-04-05 19:26:36 +00:00
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TEST_F(DBMergeOperandTest, CacheEvictedMergeOperandReadAfterFreeBug) {
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Fix PinSelf() read-after-free in DB::GetMergeOperands() (#9507)
Summary:
**Context:**
Running the new test `DBMergeOperandTest.MergeOperandReadAfterFreeBug` prior to this fix surfaces the read-after-free bug of PinSef() as below:
```
READ of size 8 at 0x60400002529d thread T0
https://github.com/facebook/rocksdb/issues/5 0x7f199a in rocksdb::PinnableSlice::PinSelf(rocksdb::Slice const&) include/rocksdb/slice.h:171
https://github.com/facebook/rocksdb/issues/6 0x7f199a in rocksdb::DBImpl::GetImpl(rocksdb::ReadOptions const&, rocksdb::Slice const&, rocksdb::DBImpl::GetImplOptions&) db/db_impl/db_impl.cc:1919
https://github.com/facebook/rocksdb/issues/7 0x540d63 in rocksdb::DBImpl::GetMergeOperands(rocksdb::ReadOptions const&, rocksdb::ColumnFamilyHandle*, rocksdb::Slice const&, rocksdb::PinnableSlice*, rocksdb::GetMergeOperandsOptions*, int*) db/db_impl/db_impl.h:203
freed by thread T0 here:
https://github.com/facebook/rocksdb/issues/3 0x1191399 in rocksdb::cache_entry_roles_detail::RegisteredDeleter<rocksdb::Block, (rocksdb::CacheEntryRole)0>::Delete(rocksdb::Slice const&, void*) cache/cache_entry_roles.h:99
https://github.com/facebook/rocksdb/issues/4 0x719348 in rocksdb::LRUHandle::Free() cache/lru_cache.h:205
https://github.com/facebook/rocksdb/issues/5 0x71047f in rocksdb::LRUCacheShard::Release(rocksdb::Cache::Handle*, bool) cache/lru_cache.cc:547
https://github.com/facebook/rocksdb/issues/6 0xa78f0a in rocksdb::Cleanable::DoCleanup() include/rocksdb/cleanable.h:60
https://github.com/facebook/rocksdb/issues/7 0xa78f0a in rocksdb::Cleanable::Reset() include/rocksdb/cleanable.h:38
https://github.com/facebook/rocksdb/issues/8 0xa78f0a in rocksdb::PinnedIteratorsManager::ReleasePinnedData() db/pinned_iterators_manager.h:71
https://github.com/facebook/rocksdb/issues/9 0xd0c21b in rocksdb::PinnedIteratorsManager::~PinnedIteratorsManager() db/pinned_iterators_manager.h:24
https://github.com/facebook/rocksdb/issues/10 0xd0c21b in rocksdb::Version::Get(rocksdb::ReadOptions const&, rocksdb::LookupKey const&, rocksdb::PinnableSlice*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*, rocksdb::Status*, rocksdb::MergeContext*, unsigned long*, bool*, bool*, unsigned long*, rocksdb::ReadCallback*, bool*, bool) db/pinned_iterators_manager.h:22
https://github.com/facebook/rocksdb/issues/11 0x7f0fdf in rocksdb::DBImpl::GetImpl(rocksdb::ReadOptions const&, rocksdb::Slice const&, rocksdb::DBImpl::GetImplOptions&) db/db_impl/db_impl.cc:1886
https://github.com/facebook/rocksdb/issues/12 0x540d63 in rocksdb::DBImpl::GetMergeOperands(rocksdb::ReadOptions const&, rocksdb::ColumnFamilyHandle*, rocksdb::Slice const&, rocksdb::PinnableSlice*, rocksdb::GetMergeOperandsOptions*, int*) db/db_impl/db_impl.h:203
previously allocated by thread T0 here:
https://github.com/facebook/rocksdb/issues/1 0x1239896 in rocksdb::AllocateBlock(unsigned long, **rocksdb::MemoryAllocator*)** memory/memory_allocator.h:35
https://github.com/facebook/rocksdb/issues/2 0x1239896 in rocksdb::BlockFetcher::CopyBufferToHeapBuf() table/block_fetcher.cc:171
https://github.com/facebook/rocksdb/issues/3 0x1239896 in rocksdb::BlockFetcher::GetBlockContents() table/block_fetcher.cc:206
https://github.com/facebook/rocksdb/issues/4 0x122eae5 in rocksdb::BlockFetcher::ReadBlockContents() table/block_fetcher.cc:325
https://github.com/facebook/rocksdb/issues/5 0x11b1f45 in rocksdb::Status rocksdb::BlockBasedTable::MaybeReadBlockAndLoadToCache<rocksdb::Block>(rocksdb::FilePrefetchBuffer*, rocksdb::ReadOptions const&, rocksdb::BlockHandle const&, rocksdb::UncompressionDict const&, bool, rocksdb::CachableEntry<rocksdb::Block>*, rocksdb::BlockType, rocksdb::GetContext*, rocksdb::BlockCacheLookupContext*, rocksdb::BlockContents*) const table/block_based/block_based_table_reader.cc:1503
```
Here is the analysis:
- We have [PinnedIteratorsManager](https://github.com/facebook/rocksdb/blob/6.28.fb/db/version_set.cc#L1980) with `Cleanable` capability in our `Version::Get()` path. It's responsible for managing the life-time of pinned iterator and invoking registered cleanup functions during its own destruction.
- For example in case above, the merge operands's clean-up gets associated with this manger in [GetContext::push_operand](https://github.com/facebook/rocksdb/blob/6.28.fb/table/get_context.cc#L405). During PinnedIteratorsManager's [destruction](https://github.com/facebook/rocksdb/blob/6.28.fb/db/pinned_iterators_manager.h#L67), the release function associated with those merge operand data is invoked.
**And that's what we see in "freed by thread T955 here" in ASAN.**
- Bug 🐛: `PinnedIteratorsManager` is local to `Version::Get()` while the data of merge operands need to outlive `Version::Get` and stay till they get [PinSelf()](https://github.com/facebook/rocksdb/blob/6.28.fb/db/db_impl/db_impl.cc#L1905), **which is the read-after-free in ASAN.**
- This bug is likely to be an overlook of `PinnedIteratorsManager` when developing the API `DB::GetMergeOperands` cuz the current logic works fine with the existing case of getting the *merged value* where the operands do not need to live that long.
- This bug was not surfaced much (even in its unit test) due to the release function associated with the merge operands (which are actually blocks put in cache as you can see in `BlockBasedTable::MaybeReadBlockAndLoadToCache` **in "previously allocated by" in ASAN report**) is a cache entry deleter.
The deleter will call `Cache::Release()` which, for LRU cache, won't immediately deallocate the block based on LRU policy [unless the cache is full or being instructed to force erase](https://github.com/facebook/rocksdb/blob/6.28.fb/cache/lru_cache.cc#L521-L531)
- `DBMergeOperandTest.MergeOperandReadAfterFreeBug` makes the cache extremely small to force cache full.
**Summary:**
- Fix the bug by align `PinnedIteratorsManager`'s lifetime with the merge operands
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9507
Test Plan:
- New test `DBMergeOperandTest.MergeOperandReadAfterFreeBug`
- db bench on read path
- Setup (LSM tree with several levels, cache the whole db to avoid read IO, warm cache with readseq to avoid read IO): `TEST_TMPDIR=/dev/shm/rocksdb ./db_bench -benchmarks="fillrandom,readseq -num=1000000 -cache_size=100000000 -write_buffer_size=10000 -statistics=1 -max_bytes_for_level_base=10000 -level0_file_num_compaction_trigger=1``TEST_TMPDIR=/dev/shm/rocksdb ./db_bench -benchmarks="readrandom" -num=1000000 -cache_size=100000000 `
- Actual command run (run 20-run for 20 times and then average the 20-run's average micros/op)
- `for j in {1..20}; do (for i in {1..20}; do rm -rf /dev/shm/rocksdb/ && TEST_TMPDIR=/dev/shm/rocksdb ./db_bench -benchmarks="fillrandom,readseq,readrandom" -num=1000000 -cache_size=100000000 -write_buffer_size=10000 -statistics=1 -max_bytes_for_level_base=10000 -level0_file_num_compaction_trigger=1 | egrep 'readrandom'; done > rr_output_pre.txt && (awk '{sum+=$3; sum_sqrt+=$3^2}END{print sum/20, sqrt(sum_sqrt/20-(sum/20)^2)}' rr_output_pre.txt) >> rr_output_pre_2.txt); done`
- **Result: Pre-change: 3.79193 micros/op; Post-change: 3.79528 micros/op (+0.09%)**
(pre-change)sorted avg micros/op of each 20-run | std of micros/op of each 20-run | (post-change) sorted avg micros/op of each 20-run | std of micros/op of each 20-run
-- | -- | -- | --
3.58355 | 0.265209 | 3.48715 | 0.382076
3.58845 | 0.519927 | 3.5832 | 0.382726
3.66415 | 0.452097 | 3.677 | 0.563831
3.68495 | 0.430897 | 3.68405 | 0.495355
3.70295 | 0.482893 | 3.68465 | 0.431438
3.719 | 0.463806 | 3.71945 | 0.457157
3.7393 | 0.453423 | 3.72795 | 0.538604
3.7806 | 0.527613 | 3.75075 | 0.444509
3.7817 | 0.426704 | 3.7683 | 0.468065
3.809 | 0.381033 | 3.8086 | 0.557378
3.80985 | 0.466011 | 3.81805 | 0.524833
3.8165 | 0.500351 | 3.83405 | 0.529339
3.8479 | 0.430326 | 3.86285 | 0.44831
3.85125 | 0.434108 | 3.8717 | 0.544098
3.8556 | 0.524602 | 3.895 | 0.411679
3.8656 | 0.476383 | 3.90965 | 0.566636
3.8911 | 0.488477 | 3.92735 | 0.608038
3.898 | 0.493978 | 3.9439 | 0.524511
3.97235 | 0.515008 | 3.9623 | 0.477416
3.9768 | 0.519993 | 3.98965 | 0.521481
- CI
Reviewed By: ajkr
Differential Revision: D34030519
Pulled By: hx235
fbshipit-source-id: a99ac585c11704c5ed93af033cb29ba0a7b16ae8
2022-02-15 20:24:05 +00:00
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// There was a bug of reading merge operands after they are mistakely freed
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// in DB::GetMergeOperands, which is surfaced by cache full.
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// See PR#9507 for more.
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Options options;
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options.create_if_missing = true;
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options.merge_operator = MergeOperators::CreateStringAppendOperator();
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options.env = env_;
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BlockBasedTableOptions table_options;
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// Small cache to simulate cache full
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table_options.block_cache = NewLRUCache(1);
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options.table_factory.reset(NewBlockBasedTableFactory(table_options));
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Reopen(options);
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int num_records = 4;
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int number_of_operands = 0;
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std::vector<PinnableSlice> values(num_records);
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GetMergeOperandsOptions merge_operands_info;
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merge_operands_info.expected_max_number_of_operands = num_records;
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ASSERT_OK(Merge("k1", "v1"));
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ASSERT_OK(Flush());
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ASSERT_OK(Merge("k1", "v2"));
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ASSERT_OK(Flush());
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ASSERT_OK(Merge("k1", "v3"));
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ASSERT_OK(Flush());
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ASSERT_OK(Merge("k1", "v4"));
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ASSERT_OK(db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(),
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"k1", values.data(), &merge_operands_info,
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&number_of_operands));
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ASSERT_EQ(number_of_operands, 4);
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ASSERT_EQ(values[0].ToString(), "v1");
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ASSERT_EQ(values[1].ToString(), "v2");
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ASSERT_EQ(values[2].ToString(), "v3");
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ASSERT_EQ(values[3].ToString(), "v4");
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}
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Fix GetMergeOperands() heap-use-after-free on flushed memtable (#9805)
Summary:
Fixes https://github.com/facebook/rocksdb/issues/9066.
Prior to the fix in this PR, this PR's unit test reported the following error under ASAN:
```
==2175705==ERROR: AddressSanitizer: heap-use-after-free on address 0x61f0000012a5 at pc 0x7f0fc36e76ce bp 0x7ffc103e9ca0 sp 0x7ffc103e9450
READ of size 5 at 0x61f0000012a5 thread T0
#0 0x7f0fc36e76cd in __interceptor_memcpy /home/engshare/third-party2/gcc/9.x/src/gcc-10.x/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:790
https://github.com/facebook/rocksdb/issues/1 0x7f0fc35a207e in std::char_traits<char>::copy(char*, char const*, unsigned long) /home/engshare/third-party2/libgcc/9.x/src/gcc-9.x/x86_64-facebook-linux/libstdc++-v3/include/bits/char_traits.h:365
https://github.com/facebook/rocksdb/issues/2 0x7f0fc35a207e in std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_S_copy(char*, char const*, unsigned long) /home/engshare/third-party2/libgcc/9.x/src/gcc-9.x/x86_64-facebook-linux/libstdc++-v3/include/bits/basic_string.h:351
https://github.com/facebook/rocksdb/issues/3 0x7f0fc35a207e in std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_replace(unsigned long, unsigned long, char const*, unsigned long) /home/engshare/third-party2/libgcc/9.x/src/gcc-9.x/x86_64-facebook-linux/libstdc++-v3/include/bits/basic_string.tcc:440
https://github.com/facebook/rocksdb/issues/4 0x8679ca in std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::assign(char const*, unsigned long) /mnt/gvfs/third-party2/libgcc/4959b39cfbe5965a37c861c4c327fa7c5c759b87/9.x/platform009/9202ce7/include/c++/9.3.0/bits/basic_string.h:1422
https://github.com/facebook/rocksdb/issues/5 0x8679ca in rocksdb::PinnableSlice::PinSelf(rocksdb::Slice const&) include/rocksdb/slice.h:171
https://github.com/facebook/rocksdb/issues/6 0x8679ca in rocksdb::DBImpl::GetImpl(rocksdb::ReadOptions const&, rocksdb::Slice const&, rocksdb::DBImpl::GetImplOptions&) db/db_impl/db_impl.cc:1930
https://github.com/facebook/rocksdb/issues/7 0x547324 in rocksdb::DBImpl::GetMergeOperands(rocksdb::ReadOptions const&, rocksdb::ColumnFamilyHandle*, rocksdb::Slice const&, rocksdb::PinnableSlice*, rocksdb::GetMergeOperandsOptions*, int*) db/db_impl/db_impl.h:203
https://github.com/facebook/rocksdb/issues/8 0x547324 in rocksdb::DBMergeOperandTest_FlushedMergeOperandReadAfterFreeBug_Test::TestBody() db/db_merge_operand_test.cc:117
https://github.com/facebook/rocksdb/issues/9 0x7241da in void testing::internal::HandleSehExceptionsInMethodIfSupported<testing::Test, void>(testing::Test*, void (testing::Test::*)(), char const*) third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3899
https://github.com/facebook/rocksdb/issues/10 0x7241da in void testing::internal::HandleExceptionsInMethodIfSupported<testing::Test, void>(testing::Test*, void (testing::Test::*)(), char const*) third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3935
https://github.com/facebook/rocksdb/issues/11 0x701a47 in testing::Test::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3973
https://github.com/facebook/rocksdb/issues/12 0x702040 in testing::Test::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3965
https://github.com/facebook/rocksdb/issues/13 0x702040 in testing::TestInfo::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:4149
https://github.com/facebook/rocksdb/issues/14 0x7025f7 in testing::TestInfo::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:4124
https://github.com/facebook/rocksdb/issues/15 0x7025f7 in testing::TestCase::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:4267
https://github.com/facebook/rocksdb/issues/16 0x704217 in testing::TestCase::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:4253
https://github.com/facebook/rocksdb/issues/17 0x704217 in testing::internal::UnitTestImpl::RunAllTests() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:6633
https://github.com/facebook/rocksdb/issues/18 0x72505a in bool testing::internal::HandleSehExceptionsInMethodIfSupported<testing::internal::UnitTestImpl, bool>(testing::internal::UnitTestImpl*, bool (testing::internal::UnitTestImpl::*)(), char const*) third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3899
https://github.com/facebook/rocksdb/issues/19 0x72505a in bool testing::internal::HandleExceptionsInMethodIfSupported<testing::internal::UnitTestImpl, bool>(testing::internal::UnitTestImpl*, bool (testing::internal::UnitTestImpl::*)(), char const*) third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3935
https://github.com/facebook/rocksdb/issues/20 0x704aa1 in testing::UnitTest::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:6242
https://github.com/facebook/rocksdb/issues/21 0x4c4aff in RUN_ALL_TESTS() third-party/gtest-1.8.1/fused-src/gtest/gtest.h:22110
https://github.com/facebook/rocksdb/issues/22 0x4c4aff in main db/db_merge_operand_test.cc:404
https://github.com/facebook/rocksdb/issues/23 0x7f0fc3108dc4 in __libc_start_main ../csu/libc-start.c:308
https://github.com/facebook/rocksdb/issues/24 0x5445fd in _start (/data/users/andrewkr/rocksdb/db_merge_operand_test+0x5445fd)
0x61f0000012a5 is located 1061 bytes inside of 3264-byte region [0x61f000000e80,0x61f000001b40)
freed by thread T0 here:
#0 0x7f0fc375b6af in operator delete(void*, unsigned long) /home/engshare/third-party2/gcc/9.x/src/gcc-10.x/libsanitizer/asan/asan_new_delete.cc:177
https://github.com/facebook/rocksdb/issues/1 0x743be8 in rocksdb::SuperVersion::~SuperVersion() db/column_family.cc:432
https://github.com/facebook/rocksdb/issues/2 0x8052aa in rocksdb::DBImpl::CleanupSuperVersion(rocksdb::SuperVersion*) db/db_impl/db_impl.cc:3534
https://github.com/facebook/rocksdb/issues/3 0x8676c2 in rocksdb::DBImpl::ReturnAndCleanupSuperVersion(rocksdb::ColumnFamilyData*, rocksdb::SuperVersion*) db/db_impl/db_impl.cc:3544
https://github.com/facebook/rocksdb/issues/4 0x8676c2 in rocksdb::DBImpl::GetImpl(rocksdb::ReadOptions const&, rocksdb::Slice const&, rocksdb::DBImpl::GetImplOptions&) db/db_impl/db_impl.cc:1911
https://github.com/facebook/rocksdb/issues/5 0x547324 in rocksdb::DBImpl::GetMergeOperands(rocksdb::ReadOptions const&, rocksdb::ColumnFamilyHandle*, rocksdb::Slice const&, rocksdb::PinnableSlice*, rocksdb::GetMergeOperandsOptions*, int*) db/db_impl/db_impl.h:203
https://github.com/facebook/rocksdb/issues/6 0x547324 in rocksdb::DBMergeOperandTest_FlushedMergeOperandReadAfterFreeBug_Test::TestBody() db/db_merge_operand_test.cc:117
https://github.com/facebook/rocksdb/issues/7 0x7241da in void testing::internal::HandleSehExceptionsInMethodIfSupported<testing::Test, void>(testing::Test*, void (testing::Test::*)(), char const*) third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3899
https://github.com/facebook/rocksdb/issues/8 0x7241da in void testing::internal::HandleExceptionsInMethodIfSupported<testing::Test, void>(testing::Test*, void (testing::Test::*)(), char const*) third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3935
https://github.com/facebook/rocksdb/issues/9 0x701a47 in testing::Test::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3973
https://github.com/facebook/rocksdb/issues/10 0x702040 in testing::Test::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3965
https://github.com/facebook/rocksdb/issues/11 0x702040 in testing::TestInfo::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:4149
https://github.com/facebook/rocksdb/issues/12 0x7025f7 in testing::TestInfo::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:4124
https://github.com/facebook/rocksdb/issues/13 0x7025f7 in testing::TestCase::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:4267
https://github.com/facebook/rocksdb/issues/14 0x704217 in testing::TestCase::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:4253
https://github.com/facebook/rocksdb/issues/15 0x704217 in testing::internal::UnitTestImpl::RunAllTests() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:6633
https://github.com/facebook/rocksdb/issues/16 0x72505a in bool testing::internal::HandleSehExceptionsInMethodIfSupported<testing::internal::UnitTestImpl, bool>(testing::internal::UnitTestImpl*, bool (testing::internal::UnitTestImpl::*)(), char const*) third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3899
https://github.com/facebook/rocksdb/issues/17 0x72505a in bool testing::internal::HandleExceptionsInMethodIfSupported<testing::internal::UnitTestImpl, bool>(testing::internal::UnitTestImpl*, bool (testing::internal::UnitTestImpl::*)(), char const*) third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:3935
https://github.com/facebook/rocksdb/issues/18 0x704aa1 in testing::UnitTest::Run() third-party/gtest-1.8.1/fused-src/gtest/gtest-all.cc:6242
https://github.com/facebook/rocksdb/issues/19 0x4c4aff in RUN_ALL_TESTS() third-party/gtest-1.8.1/fused-src/gtest/gtest.h:22110
https://github.com/facebook/rocksdb/issues/20 0x4c4aff in main db/db_merge_operand_test.cc:404
https://github.com/facebook/rocksdb/issues/21 0x7f0fc3108dc4 in __libc_start_main ../csu/libc-start.c:308
https://github.com/facebook/rocksdb/issues/22 0x5445fd in _start (/data/users/andrewkr/rocksdb/db_merge_operand_test+0x5445fd)
...
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9805
Test Plan: following the fix in this PR, the new unit test passes
Reviewed By: jay-zhuang
Differential Revision: D35388415
Pulled By: ajkr
fbshipit-source-id: b39c5d002155906c8abc4a3429eca696dbf916d0
2022-04-05 19:26:36 +00:00
|
|
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TEST_F(DBMergeOperandTest, FlushedMergeOperandReadAfterFreeBug) {
|
|
|
|
|
// Repro for a bug where a memtable containing a merge operand could be
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|
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|
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// deleted before the merge operand was saved to the result.
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auto options = CurrentOptions();
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options.merge_operator = MergeOperators::CreateStringAppendOperator();
|
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Reopen(options);
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ASSERT_OK(Merge("key", "value"));
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ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->LoadDependency(
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{{"DBImpl::GetImpl:PostMemTableGet:0",
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"DBMergeOperandTest::FlushedMergeOperandReadAfterFreeBug:PreFlush"},
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{"DBMergeOperandTest::FlushedMergeOperandReadAfterFreeBug:PostFlush",
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"DBImpl::GetImpl:PostMemTableGet:1"}});
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ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->EnableProcessing();
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auto flush_thread = port::Thread([&]() {
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TEST_SYNC_POINT(
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"DBMergeOperandTest::FlushedMergeOperandReadAfterFreeBug:PreFlush");
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ASSERT_OK(Flush());
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TEST_SYNC_POINT(
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"DBMergeOperandTest::FlushedMergeOperandReadAfterFreeBug:PostFlush");
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});
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PinnableSlice value;
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GetMergeOperandsOptions merge_operands_info;
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merge_operands_info.expected_max_number_of_operands = 1;
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int number_of_operands;
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ASSERT_OK(db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(),
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"key", &value, &merge_operands_info,
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&number_of_operands));
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ASSERT_EQ(1, number_of_operands);
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flush_thread.join();
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}
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2021-06-10 19:55:29 +00:00
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TEST_F(DBMergeOperandTest, GetMergeOperandsBasic) {
|
New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
|
|
|
Options options;
|
|
|
|
|
options.create_if_missing = true;
|
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|
|
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// Use only the latest two merge operands.
|
|
|
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|
options.merge_operator = std::make_shared<LimitedStringAppendMergeOp>(2, ',');
|
|
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options.env = env_;
|
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|
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|
Reopen(options);
|
|
|
|
|
int num_records = 4;
|
|
|
|
|
int number_of_operands = 0;
|
|
|
|
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std::vector<PinnableSlice> values(num_records);
|
|
|
|
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GetMergeOperandsOptions merge_operands_info;
|
|
|
|
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merge_operands_info.expected_max_number_of_operands = num_records;
|
|
|
|
|
|
|
|
|
|
// k0 value in memtable
|
2020-12-08 23:53:59 +00:00
|
|
|
ASSERT_OK(Put("k0", "PutARock"));
|
|
|
|
|
ASSERT_OK(db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(),
|
|
|
|
|
"k0", values.data(), &merge_operands_info,
|
|
|
|
|
&number_of_operands));
|
New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
|
|
|
ASSERT_EQ(values[0], "PutARock");
|
|
|
|
|
|
|
|
|
|
// k0.1 value in SST
|
2020-12-08 23:53:59 +00:00
|
|
|
ASSERT_OK(Put("k0.1", "RockInSST"));
|
New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
|
|
|
ASSERT_OK(Flush());
|
2020-12-08 23:53:59 +00:00
|
|
|
ASSERT_OK(db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(),
|
|
|
|
|
"k0.1", values.data(), &merge_operands_info,
|
|
|
|
|
&number_of_operands));
|
New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
|
|
|
ASSERT_EQ(values[0], "RockInSST");
|
|
|
|
|
|
|
|
|
|
// All k1 values are in memtable.
|
|
|
|
|
ASSERT_OK(Merge("k1", "a"));
|
2020-12-08 23:53:59 +00:00
|
|
|
ASSERT_OK(Put("k1", "x"));
|
New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
|
|
|
ASSERT_OK(Merge("k1", "b"));
|
|
|
|
|
ASSERT_OK(Merge("k1", "c"));
|
|
|
|
|
ASSERT_OK(Merge("k1", "d"));
|
2020-12-08 23:53:59 +00:00
|
|
|
ASSERT_OK(db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(),
|
|
|
|
|
"k1", values.data(), &merge_operands_info,
|
|
|
|
|
&number_of_operands));
|
New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
|
|
|
ASSERT_EQ(values[0], "x");
|
|
|
|
|
ASSERT_EQ(values[1], "b");
|
|
|
|
|
ASSERT_EQ(values[2], "c");
|
|
|
|
|
ASSERT_EQ(values[3], "d");
|
|
|
|
|
|
|
|
|
|
// expected_max_number_of_operands is less than number of merge operands so
|
|
|
|
|
// status should be Incomplete.
|
|
|
|
|
merge_operands_info.expected_max_number_of_operands = num_records - 1;
|
|
|
|
|
Status status = db_->GetMergeOperands(
|
|
|
|
|
ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(),
|
|
|
|
|
&merge_operands_info, &number_of_operands);
|
|
|
|
|
ASSERT_EQ(status.IsIncomplete(), true);
|
|
|
|
|
merge_operands_info.expected_max_number_of_operands = num_records;
|
|
|
|
|
|
|
|
|
|
// All k1.1 values are in memtable.
|
|
|
|
|
ASSERT_OK(Merge("k1.1", "r"));
|
2020-12-08 23:53:59 +00:00
|
|
|
ASSERT_OK(Delete("k1.1"));
|
New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
|
|
|
ASSERT_OK(Merge("k1.1", "c"));
|
|
|
|
|
ASSERT_OK(Merge("k1.1", "k"));
|
|
|
|
|
ASSERT_OK(Merge("k1.1", "s"));
|
2020-12-08 23:53:59 +00:00
|
|
|
ASSERT_OK(db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(),
|
|
|
|
|
"k1.1", values.data(), &merge_operands_info,
|
|
|
|
|
&number_of_operands));
|
New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
|
|
|
ASSERT_EQ(values[0], "c");
|
|
|
|
|
ASSERT_EQ(values[1], "k");
|
|
|
|
|
ASSERT_EQ(values[2], "s");
|
|
|
|
|
|
|
|
|
|
// All k2 values are flushed to L0 into a single file.
|
|
|
|
|
ASSERT_OK(Merge("k2", "q"));
|
|
|
|
|
ASSERT_OK(Merge("k2", "w"));
|
|
|
|
|
ASSERT_OK(Merge("k2", "e"));
|
|
|
|
|
ASSERT_OK(Merge("k2", "r"));
|
|
|
|
|
ASSERT_OK(Flush());
|
2020-12-08 23:53:59 +00:00
|
|
|
ASSERT_OK(db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(),
|
|
|
|
|
"k2", values.data(), &merge_operands_info,
|
|
|
|
|
&number_of_operands));
|
New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
|
|
|
ASSERT_EQ(values[0], "q");
|
|
|
|
|
ASSERT_EQ(values[1], "w");
|
|
|
|
|
ASSERT_EQ(values[2], "e");
|
|
|
|
|
ASSERT_EQ(values[3], "r");
|
|
|
|
|
|
|
|
|
|
// All k2.1 values are flushed to L0 into a single file.
|
|
|
|
|
ASSERT_OK(Merge("k2.1", "m"));
|
2020-12-08 23:53:59 +00:00
|
|
|
ASSERT_OK(Put("k2.1", "l"));
|
New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
|
|
|
ASSERT_OK(Merge("k2.1", "n"));
|
|
|
|
|
ASSERT_OK(Merge("k2.1", "o"));
|
|
|
|
|
ASSERT_OK(Flush());
|
2020-12-08 23:53:59 +00:00
|
|
|
ASSERT_OK(db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(),
|
|
|
|
|
"k2.1", values.data(), &merge_operands_info,
|
|
|
|
|
&number_of_operands));
|
New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
|
|
|
ASSERT_EQ(values[0], "l,n,o");
|
|
|
|
|
|
|
|
|
|
// All k2.2 values are flushed to L0 into a single file.
|
|
|
|
|
ASSERT_OK(Merge("k2.2", "g"));
|
2020-12-08 23:53:59 +00:00
|
|
|
ASSERT_OK(Delete("k2.2"));
|
New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
|
|
|
ASSERT_OK(Merge("k2.2", "o"));
|
|
|
|
|
ASSERT_OK(Merge("k2.2", "t"));
|
|
|
|
|
ASSERT_OK(Flush());
|
2020-12-08 23:53:59 +00:00
|
|
|
ASSERT_OK(db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(),
|
|
|
|
|
"k2.2", values.data(), &merge_operands_info,
|
|
|
|
|
&number_of_operands));
|
New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
|
|
|
ASSERT_EQ(values[0], "o,t");
|
|
|
|
|
|
|
|
|
|
// Do some compaction that will make the following tests more predictable
|
|
|
|
|
// Slice start("PutARock");
|
|
|
|
|
// Slice end("t");
|
2020-12-08 23:53:59 +00:00
|
|
|
ASSERT_OK(db_->CompactRange(CompactRangeOptions(), nullptr, nullptr));
|
New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
|
|
|
|
|
|
|
|
// All k3 values are flushed and are in different files.
|
|
|
|
|
ASSERT_OK(Merge("k3", "ab"));
|
|
|
|
|
ASSERT_OK(Flush());
|
|
|
|
|
ASSERT_OK(Merge("k3", "bc"));
|
|
|
|
|
ASSERT_OK(Flush());
|
|
|
|
|
ASSERT_OK(Merge("k3", "cd"));
|
|
|
|
|
ASSERT_OK(Flush());
|
|
|
|
|
ASSERT_OK(Merge("k3", "de"));
|
2020-12-08 23:53:59 +00:00
|
|
|
ASSERT_OK(db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(),
|
|
|
|
|
"k3", values.data(), &merge_operands_info,
|
|
|
|
|
&number_of_operands));
|
New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
|
|
|
ASSERT_EQ(values[0], "ab");
|
|
|
|
|
ASSERT_EQ(values[1], "bc");
|
|
|
|
|
ASSERT_EQ(values[2], "cd");
|
|
|
|
|
ASSERT_EQ(values[3], "de");
|
|
|
|
|
|
|
|
|
|
// All k3.1 values are flushed and are in different files.
|
|
|
|
|
ASSERT_OK(Merge("k3.1", "ab"));
|
|
|
|
|
ASSERT_OK(Flush());
|
2020-12-08 23:53:59 +00:00
|
|
|
ASSERT_OK(Put("k3.1", "bc"));
|
New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
|
|
|
ASSERT_OK(Flush());
|
|
|
|
|
ASSERT_OK(Merge("k3.1", "cd"));
|
|
|
|
|
ASSERT_OK(Flush());
|
|
|
|
|
ASSERT_OK(Merge("k3.1", "de"));
|
2020-12-08 23:53:59 +00:00
|
|
|
ASSERT_OK(db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(),
|
|
|
|
|
"k3.1", values.data(), &merge_operands_info,
|
|
|
|
|
&number_of_operands));
|
New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
|
|
|
ASSERT_EQ(values[0], "bc");
|
|
|
|
|
ASSERT_EQ(values[1], "cd");
|
|
|
|
|
ASSERT_EQ(values[2], "de");
|
|
|
|
|
|
|
|
|
|
// All k3.2 values are flushed and are in different files.
|
|
|
|
|
ASSERT_OK(Merge("k3.2", "ab"));
|
|
|
|
|
ASSERT_OK(Flush());
|
2020-12-08 23:53:59 +00:00
|
|
|
ASSERT_OK(Delete("k3.2"));
|
New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
|
|
|
ASSERT_OK(Flush());
|
|
|
|
|
ASSERT_OK(Merge("k3.2", "cd"));
|
|
|
|
|
ASSERT_OK(Flush());
|
|
|
|
|
ASSERT_OK(Merge("k3.2", "de"));
|
2020-12-08 23:53:59 +00:00
|
|
|
ASSERT_OK(db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(),
|
|
|
|
|
"k3.2", values.data(), &merge_operands_info,
|
|
|
|
|
&number_of_operands));
|
New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
|
|
|
ASSERT_EQ(values[0], "cd");
|
|
|
|
|
ASSERT_EQ(values[1], "de");
|
|
|
|
|
|
|
|
|
|
// All K4 values are in different levels
|
|
|
|
|
ASSERT_OK(Merge("k4", "ba"));
|
|
|
|
|
ASSERT_OK(Flush());
|
|
|
|
|
MoveFilesToLevel(4);
|
|
|
|
|
ASSERT_OK(Merge("k4", "cb"));
|
|
|
|
|
ASSERT_OK(Flush());
|
|
|
|
|
MoveFilesToLevel(3);
|
|
|
|
|
ASSERT_OK(Merge("k4", "dc"));
|
|
|
|
|
ASSERT_OK(Flush());
|
|
|
|
|
MoveFilesToLevel(1);
|
|
|
|
|
ASSERT_OK(Merge("k4", "ed"));
|
2020-12-08 23:53:59 +00:00
|
|
|
ASSERT_OK(db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(),
|
|
|
|
|
"k4", values.data(), &merge_operands_info,
|
|
|
|
|
&number_of_operands));
|
New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
|
|
|
ASSERT_EQ(values[0], "ba");
|
|
|
|
|
ASSERT_EQ(values[1], "cb");
|
|
|
|
|
ASSERT_EQ(values[2], "dc");
|
|
|
|
|
ASSERT_EQ(values[3], "ed");
|
|
|
|
|
|
2021-06-10 19:55:29 +00:00
|
|
|
// First 3 k5 values are in SST and next 4 k5 values are in Immutable
|
|
|
|
|
// Memtable
|
New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
|
|
|
ASSERT_OK(Merge("k5", "who"));
|
|
|
|
|
ASSERT_OK(Merge("k5", "am"));
|
|
|
|
|
ASSERT_OK(Merge("k5", "i"));
|
|
|
|
|
ASSERT_OK(Flush());
|
2020-12-08 23:53:59 +00:00
|
|
|
ASSERT_OK(Put("k5", "remember"));
|
New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
|
|
|
ASSERT_OK(Merge("k5", "i"));
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|
ASSERT_OK(Merge("k5", "am"));
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ASSERT_OK(Merge("k5", "rocks"));
|
2020-12-08 23:53:59 +00:00
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|
ASSERT_OK(dbfull()->TEST_SwitchMemtable());
|
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|
ASSERT_OK(db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(),
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|
"k5", values.data(), &merge_operands_info,
|
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|
|
|
&number_of_operands));
|
New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
|
|
|
ASSERT_EQ(values[0], "remember");
|
|
|
|
|
ASSERT_EQ(values[1], "i");
|
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|
|
ASSERT_EQ(values[2], "am");
|
|
|
|
|
}
|
|
|
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|
2021-06-10 19:55:29 +00:00
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|
TEST_F(DBMergeOperandTest, BlobDBGetMergeOperandsBasic) {
|
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Options options;
|
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|
options.create_if_missing = true;
|
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|
options.enable_blob_files = true;
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|
options.min_blob_size = 0;
|
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|
|
// Use only the latest two merge operands.
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options.merge_operator = std::make_shared<LimitedStringAppendMergeOp>(2, ',');
|
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|
options.env = env_;
|
|
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|
Reopen(options);
|
|
|
|
|
int num_records = 4;
|
|
|
|
|
int number_of_operands = 0;
|
|
|
|
|
std::vector<PinnableSlice> values(num_records);
|
|
|
|
|
GetMergeOperandsOptions merge_operands_info;
|
|
|
|
|
merge_operands_info.expected_max_number_of_operands = num_records;
|
|
|
|
|
|
|
|
|
|
// All k1 values are in memtable.
|
|
|
|
|
ASSERT_OK(Put("k1", "x"));
|
|
|
|
|
ASSERT_OK(Merge("k1", "b"));
|
|
|
|
|
ASSERT_OK(Merge("k1", "c"));
|
|
|
|
|
ASSERT_OK(Merge("k1", "d"));
|
|
|
|
|
ASSERT_OK(db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(),
|
|
|
|
|
"k1", values.data(), &merge_operands_info,
|
|
|
|
|
&number_of_operands));
|
|
|
|
|
ASSERT_EQ(values[0], "x");
|
|
|
|
|
ASSERT_EQ(values[1], "b");
|
|
|
|
|
ASSERT_EQ(values[2], "c");
|
|
|
|
|
ASSERT_EQ(values[3], "d");
|
|
|
|
|
|
|
|
|
|
// expected_max_number_of_operands is less than number of merge operands so
|
|
|
|
|
// status should be Incomplete.
|
|
|
|
|
merge_operands_info.expected_max_number_of_operands = num_records - 1;
|
|
|
|
|
Status status = db_->GetMergeOperands(
|
|
|
|
|
ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(),
|
|
|
|
|
&merge_operands_info, &number_of_operands);
|
|
|
|
|
ASSERT_EQ(status.IsIncomplete(), true);
|
|
|
|
|
merge_operands_info.expected_max_number_of_operands = num_records;
|
|
|
|
|
|
|
|
|
|
// All k2 values are flushed to L0 into a single file.
|
|
|
|
|
ASSERT_OK(Put("k2", "q"));
|
|
|
|
|
ASSERT_OK(Merge("k2", "w"));
|
|
|
|
|
ASSERT_OK(Merge("k2", "e"));
|
|
|
|
|
ASSERT_OK(Merge("k2", "r"));
|
|
|
|
|
ASSERT_OK(Flush());
|
|
|
|
|
ASSERT_OK(db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(),
|
|
|
|
|
"k2", values.data(), &merge_operands_info,
|
|
|
|
|
&number_of_operands));
|
|
|
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|
ASSERT_EQ(values[0], "q,w,e,r");
|
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|
|
|
|
|
|
|
// Do some compaction that will make the following tests more predictable
|
|
|
|
|
ASSERT_OK(db_->CompactRange(CompactRangeOptions(), nullptr, nullptr));
|
|
|
|
|
|
|
|
|
|
// All k3 values are flushed and are in different files.
|
|
|
|
|
ASSERT_OK(Put("k3", "ab"));
|
|
|
|
|
ASSERT_OK(Flush());
|
|
|
|
|
ASSERT_OK(Merge("k3", "bc"));
|
|
|
|
|
ASSERT_OK(Flush());
|
|
|
|
|
ASSERT_OK(Merge("k3", "cd"));
|
|
|
|
|
ASSERT_OK(Flush());
|
|
|
|
|
ASSERT_OK(Merge("k3", "de"));
|
|
|
|
|
ASSERT_OK(db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(),
|
|
|
|
|
"k3", values.data(), &merge_operands_info,
|
|
|
|
|
&number_of_operands));
|
|
|
|
|
ASSERT_EQ(values[0], "ab");
|
|
|
|
|
ASSERT_EQ(values[1], "bc");
|
|
|
|
|
ASSERT_EQ(values[2], "cd");
|
|
|
|
|
ASSERT_EQ(values[3], "de");
|
|
|
|
|
|
|
|
|
|
// All K4 values are in different levels
|
|
|
|
|
ASSERT_OK(Put("k4", "ba"));
|
|
|
|
|
ASSERT_OK(Flush());
|
|
|
|
|
MoveFilesToLevel(4);
|
|
|
|
|
ASSERT_OK(Merge("k4", "cb"));
|
|
|
|
|
ASSERT_OK(Flush());
|
|
|
|
|
MoveFilesToLevel(3);
|
|
|
|
|
ASSERT_OK(Merge("k4", "dc"));
|
|
|
|
|
ASSERT_OK(Flush());
|
|
|
|
|
MoveFilesToLevel(1);
|
|
|
|
|
ASSERT_OK(Merge("k4", "ed"));
|
|
|
|
|
ASSERT_OK(db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(),
|
|
|
|
|
"k4", values.data(), &merge_operands_info,
|
|
|
|
|
&number_of_operands));
|
|
|
|
|
ASSERT_EQ(values[0], "ba");
|
|
|
|
|
ASSERT_EQ(values[1], "cb");
|
|
|
|
|
ASSERT_EQ(values[2], "dc");
|
|
|
|
|
ASSERT_EQ(values[3], "ed");
|
|
|
|
|
}
|
|
|
|
|
|
Avoid allocations/copies for large `GetMergeOperands()` results (#10458)
Summary:
This PR avoids allocations and copies for the result of `GetMergeOperands()` when the average operand size is at least 256 bytes and the total operands size is at least 32KB. The `GetMergeOperands()` already included `PinnableSlice` but was calling `PinSelf()` (i.e., allocating and copying) for each operand. When this optimization takes effect, we instead call `PinSlice()` to skip that allocation and copy. Resources are pinned in order for the `PinnableSlice` to point to valid memory even after `GetMergeOperands()` returns.
The pinned resources include a referenced `SuperVersion`, a `MergingContext`, and a `PinnedIteratorsManager`. They are bundled into a `GetMergeOperandsState`. We use `SharedCleanablePtr` to share that bundle among all `PinnableSlice`s populated by `GetMergeOperands()`. That way, the last `PinnableSlice` to be `Reset()` will cleanup the bundle, including unreferencing the `SuperVersion`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10458
Test Plan:
- new DB level test
- measured benefit/regression in a number of memtable scenarios
Setup command:
```
$ ./db_bench -benchmarks=mergerandom -merge_operator=StringAppendOperator -num=$num -writes=16384 -key_size=16 -value_size=$value_sz -compression_type=none -write_buffer_size=1048576000
```
Benchmark command:
```
./db_bench -threads=$threads -use_existing_db=true -avoid_flush_during_recovery=true -write_buffer_size=1048576000 -benchmarks=readrandomoperands -merge_operator=StringAppendOperator -num=$num -duration=10
```
Worst regression is when a key has many tiny operands:
- Parameters: num=1 (implying 16384 operands per key), value_sz=8, threads=1
- `GetMergeOperands()` latency increases 682 micros -> 800 micros (+17%)
The regression disappears into the noise (<1% difference) if we remove the `Reset()` loop and the size counting loop. The former is arguably needed regardless of this PR as the convention in `Get()` and `MultiGet()` is to `Reset()` the input `PinnableSlice`s at the start. The latter could be optimized to count the size as we accumulate operands rather than after the fact.
Best improvement is when a key has large operands and high concurrency:
- Parameters: num=4 (implying 4096 operands per key), value_sz=2KB, threads=32
- `GetMergeOperands()` latency decreases 11492 micros -> 437 micros (-96%).
Reviewed By: cbi42
Differential Revision: D38336578
Pulled By: ajkr
fbshipit-source-id: 48146d127e04cb7f2d4d2939a2b9dff3aba18258
2022-08-04 07:42:13 +00:00
|
|
|
TEST_F(DBMergeOperandTest, GetMergeOperandsLargeResultOptimization) {
|
|
|
|
|
// These constants are chosen to trigger the large result optimization
|
|
|
|
|
// (pinning a bundle of `DBImpl` resources).
|
|
|
|
|
const int kNumOperands = 1024;
|
|
|
|
|
const int kOperandLen = 1024;
|
|
|
|
|
|
|
|
|
|
Options options;
|
|
|
|
|
options.create_if_missing = true;
|
|
|
|
|
options.merge_operator = MergeOperators::CreateStringAppendOperator();
|
|
|
|
|
DestroyAndReopen(options);
|
|
|
|
|
|
|
|
|
|
Random rnd(301);
|
|
|
|
|
std::vector<std::string> expected_merge_operands;
|
|
|
|
|
expected_merge_operands.reserve(kNumOperands);
|
|
|
|
|
for (int i = 0; i < kNumOperands; ++i) {
|
|
|
|
|
expected_merge_operands.emplace_back(rnd.RandomString(kOperandLen));
|
|
|
|
|
ASSERT_OK(Merge("key", expected_merge_operands.back()));
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
std::vector<PinnableSlice> merge_operands(kNumOperands);
|
|
|
|
|
GetMergeOperandsOptions merge_operands_info;
|
|
|
|
|
merge_operands_info.expected_max_number_of_operands = kNumOperands;
|
|
|
|
|
int num_merge_operands = 0;
|
|
|
|
|
ASSERT_OK(db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(),
|
|
|
|
|
"key", merge_operands.data(),
|
|
|
|
|
&merge_operands_info, &num_merge_operands));
|
|
|
|
|
ASSERT_EQ(num_merge_operands, kNumOperands);
|
|
|
|
|
|
|
|
|
|
// Ensures the large result optimization was used.
|
|
|
|
|
for (int i = 0; i < kNumOperands; ++i) {
|
|
|
|
|
ASSERT_TRUE(merge_operands[i].IsPinned());
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// Add a Flush() to change the `SuperVersion` to challenge the resource
|
|
|
|
|
// pinning.
|
|
|
|
|
ASSERT_OK(Flush());
|
|
|
|
|
|
|
|
|
|
for (int i = 0; i < kNumOperands; ++i) {
|
|
|
|
|
ASSERT_EQ(expected_merge_operands[i], merge_operands[i]);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2020-02-20 20:07:53 +00:00
|
|
|
} // namespace ROCKSDB_NAMESPACE
|
New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
|
|
|
|
|
|
|
|
int main(int argc, char** argv) {
|
2020-02-20 20:07:53 +00:00
|
|
|
ROCKSDB_NAMESPACE::port::InstallStackTraceHandler();
|
New API to get all merge operands for a Key (#5604)
Summary:
This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases:
1. Update subset of columns and read subset of columns -
Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU.
2. Updating very few attributes in a value which is a JSON-like document -
Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge.
----------------------------------------------------------------------------------------------------
API :
Status GetMergeOperands(
const ReadOptions& options, ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* merge_operands,
GetMergeOperandsOptions* get_merge_operands_options,
int* number_of_operands)
Example usage :
int size = 100;
int number_of_operands = 0;
std::vector<PinnableSlice> values(size);
GetMergeOperandsOptions merge_operands_info;
db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands);
Description :
Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion.
merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604
Test Plan:
Added unit test and perf test in db_bench that can be run using the command:
./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist
Differential Revision: D16657366
Pulled By: vjnadimpalli
fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf
2019-08-06 21:22:34 +00:00
|
|
|
::testing::InitGoogleTest(&argc, argv);
|
|
|
|
|
return RUN_ALL_TESTS();
|
|
|
|
|
}
|