Summary:
For our default block cache, each additional entry has extra memory overhead. It include LRUHandle (72 bytes currently) and the cache key (two varint64, file id and offset). The usage is not negligible. For example for block_size=4k, the overhead accounts for an extra 2% memory usage for the cache. The patch charging the cache for the extra usage, reducing untracked memory usage outside block cache. The feature is enabled by default and can be disabled by passing kDontChargeCacheMetadata to the cache constructor.
This PR builds up on https://github.com/facebook/rocksdb/issues/4258
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5797
Test Plan:
- Existing tests are updated to either disable the feature when the test has too much dependency on the old way of accounting the usage or increasing the cache capacity to account for the additional charge of metadata.
- The Usage tests in cache_test.cc are augmented to test the cache usage under kFullChargeCacheMetadata.
Differential Revision: D17396833
Pulled By: maysamyabandeh
fbshipit-source-id: 7684ccb9f8a40ca595e4f5efcdb03623afea0c6f
Summary:
Since DynamicBloom is now only used in-memory, we're free to
change it without schema compatibility issues. The new implementation
is drawn from (with manifest permission)
303542a767/bloom_simulation_tests/foo.cc (L613)
This has several speed advantages over the prior implementation:
* Uses fastrange instead of %
* Minimum logic to determine first (and all) probed memory addresses
* (Major) Two probes per 64-bit memory fetch/write.
* Very fast and effective (murmur-like) hash expansion/re-mixing. (At
least on recent CPUs, integer multiplication is very cheap.)
While a Bloom filter with 512-bit cache locality has about a 1.15x FP
rate penalty (e.g. 0.84% to 0.97%), further restricting to two probes
per 64 bits incurs an additional 1.12x FP rate penalty (e.g. 0.97% to
1.09%). Nevertheless, the unit tests show no "mediocre" FP rate samples,
unlike the old implementation with more erratic FP rates.
Especially for the memtable, we expect speed to outweigh somewhat higher
FP rates. For example, a negative table query would have to be 1000x
slower than a BF query to justify doubling BF query time to shave 10% off
FP rate (working assumption around 1% FP rate). While that seems likely
for SSTs, my data suggests a speed factor of roughly 50x for the memtable
(vs. BF; ~1.5% lower write throughput when enabling memtable Bloom
filter, after this change). Thus, it's probably not worth even 5% more
time in the Bloom filter to shave off 1/10th of the Bloom FP rate, or 0.1%
in absolute terms, and it's probably at least 20% slower to recoup that
much FP rate from this new implementation. Because of this, we do not see
a need for a 'locality' option that affects the MemTable Bloom filter
and have decoupled the MemTable Bloom filter from Options::bloom_locality.
Note that just 3% more memory to the Bloom filter (10.3 bits per key vs.
just 10) is able to make up for the ~12% FP rate drop in the new
implementation:
[] # Nearly "ideal" FP-wise but reasonably fast cache-local implementation
[~/wormhashing/bloom_simulation_tests] ./foo_gcc_IMPL_CACHE_WORM64_FROM32_any.out 10000000 6 10 $RANDOM 100000000
./foo_gcc_IMPL_CACHE_WORM64_FROM32_any.out time: 3.29372 sampled_fp_rate: 0.00985956 ...
[] # Close match to this new implementation
[~/wormhashing/bloom_simulation_tests] ./foo_gcc_IMPL_CACHE_MUL64_BLOCK_FROM32_any.out 10000000 6 10.3 $RANDOM 100000000
./foo_gcc_IMPL_CACHE_MUL64_BLOCK_FROM32_any.out time: 2.10072 sampled_fp_rate: 0.00985655 ...
[] # Old locality=1 implementation
[~/wormhashing/bloom_simulation_tests] ./foo_gcc_IMPL_CACHE_ROCKSDB_DYNAMIC_any.out 10000000 6 10 $RANDOM 100000000
./foo_gcc_IMPL_CACHE_ROCKSDB_DYNAMIC_any.out time: 3.95472 sampled_fp_rate: 0.00988943 ...
Also note the dramatic speed improvement vs. alternatives.
--
Performance unit test: DynamicBloomTest.concurrent_with_perf is updated
to report more precise timing data. (Measure running time of each
thread, not just longest running thread, etc.) Results averaged over
various sizes enabled with --enable_perf and 20 runs each; old dynamic
bloom refers to locality=1, the faster of the old:
old dynamic bloom, avg add latency = 65.6468
new dynamic bloom, avg add latency = 44.3809
old dynamic bloom, avg query latency = 50.6485
new dynamic bloom, avg query latency = 43.2186
old avg parallel add latency = 41.678
new avg parallel add latency = 24.5238
old avg parallel hit latency = 14.6322
new avg parallel hit latency = 12.3939
old avg parallel miss latency = 16.7289
new avg parallel miss latency = 12.2134
Tested on a dedicated 64-bit production machine at Facebook. Significant
improvement all around.
Despite now using std::atomic<uint64_t>, quick before-and-after test on
a 32-bit machine (Intel Atom N270, released 2008) shows no regression in
performance, in some cases modest improvement.
--
Performance integration test (synthetic): with DEBUG_LEVEL=0, used
TEST_TMPDIR=/dev/shm ./db_bench --benchmarks=fillrandom,readmissing,readrandom,stats --num=2000000
and optionally with -memtable_whole_key_filtering -memtable_bloom_size_ratio=0.01
300 runs each configuration.
Write throughput change by enabling memtable bloom:
Old locality=0: -3.06%
Old locality=1: -2.37%
New: -1.50%
conclusion -> seems to substantially close the gap
Readmissing throughput change by enabling memtable bloom:
Old locality=0: +34.47%
Old locality=1: +34.80%
New: +33.25%
conclusion -> maybe a small new penalty from FP rate
Readrandom throughput change by enabling memtable bloom:
Old locality=0: +31.54%
Old locality=1: +31.13%
New: +30.60%
conclusion -> maybe also from FP rate (after memtable flush)
--
Another conclusion we can draw from this new implementation is that the
existing 32-bit hash function is not inherently crippling the Bloom
filter speed or accuracy, below about 5 million keys. For speed, the
implementation is essentially the same whether starting with 32-bits or
64-bits of hash; it just determines whether the first multiplication
after fastrange is a pseudorandom expansion or needed re-mix. Note that
this multiplication can occur while memory is fetching.
For accuracy, in a standard configuration, you need about 5 million
keys before you have about a 1.1x FP penalty due to using a
32-bit hash vs. 64-bit:
[~/wormhashing/bloom_simulation_tests] ./foo_gcc_IMPL_CACHE_MUL64_BLOCK_FROM32_any.out $((5 * 1000 * 1000 * 10)) 6 10 $RANDOM 100000000
./foo_gcc_IMPL_CACHE_MUL64_BLOCK_FROM32_any.out time: 2.52069 sampled_fp_rate: 0.0118267 ...
[~/wormhashing/bloom_simulation_tests] ./foo_gcc_IMPL_CACHE_MUL64_BLOCK_any.out $((5 * 1000 * 1000 * 10)) 6 10 $RANDOM 100000000
./foo_gcc_IMPL_CACHE_MUL64_BLOCK_any.out time: 2.43871 sampled_fp_rate: 0.0109059
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5762
Differential Revision: D17214194
Pulled By: pdillinger
fbshipit-source-id: ad9da031772e985fd6b62a0e1db8e81892520595
Summary:
Adding a light weight API to get last live WAL file name and size. Meant to be used as a helper for backup/restore tooling in a larger ecosystem such as MySQL with a MyRocks storage engine.
Specifically within MySQL's backup/restore mechanism, this call can be made with a write lock on the mysql db to get a transactionally consistent snapshot of the current WAL file position along with other non-rocksdb log/data files.
Without this, the alternative would be to take the aforementioned lock, scan the WAL dir for all files, find the last file and note its exact size as the rocksdb 'checkpoint'.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5765
Differential Revision: D17172717
Pulled By: affandar
fbshipit-source-id: f2fabafd4c0e6fc45f126670c8c88a9f84cb8a37
Summary:
Before this PR, when the number of column families involved in a file ingestion exceeds 2, a bug in the looping logic prevents correct file number being assigned to each ingestion job.
Also skip deleting non-existing hard links during cleanup-after-failure.
Test plan (devserver)
```
$COMPILE_WITH_ASAN=1 make all
$./external_sst_file_test --gtest_filter=ExternalSSTFileTest/ExternalSSTFileTest.IngestFilesIntoMultipleColumnFamilies_*/*
$makke check
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5760
Differential Revision: D17142982
Pulled By: riversand963
fbshipit-source-id: 06c1847a4e7a402647bcf28d124e70f2a0f9daf6
Summary:
Open-source users recently reported two occurrences of LSM-tree corruption (https://github.com/facebook/rocksdb/issues/5558 is one), which would be caught by options.force_consistency_checks = true. options.force_consistency_checks has a usability limitation because it crashes the service once inconsistency is detected. This makes the feature hard to use. Most users serve from multiple RocksDB shards per server and the impacts of crashing the service is higher than it should be.
Instead, we just pass the error back to users without killing the service, and ask them to deal with the problem accordingly.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5744
Differential Revision: D17096940
Pulled By: pdhandharia
fbshipit-source-id: b6780039044e265f26ed2ad03c51f4abbe8b603c
Summary:
MyRocks currently sets `max_write_buffer_number_to_maintain` in order to maintain enough history for transaction conflict checking. The effectiveness of this approach depends on the size of memtables. When memtables are small, it may not keep enough history; when memtables are large, this may consume too much memory.
We are proposing a new way to configure memtable list history: by limiting the memory usage of immutable memtables. The new option is `max_write_buffer_size_to_maintain` and it will take precedence over the old `max_write_buffer_number_to_maintain` if they are both set to non-zero values. The new option accounts for the total memory usage of flushed immutable memtables and mutable memtable. When the total usage exceeds the limit, RocksDB may start dropping immutable memtables (which is also called trimming history), starting from the oldest one.
The semantics of the old option actually works both as an upper bound and lower bound. History trimming will start if number of immutable memtables exceeds the limit, but it will never go below (limit-1) due to history trimming.
In order the mimic the behavior with the new option, history trimming will stop if dropping the next immutable memtable causes the total memory usage go below the size limit. For example, assuming the size limit is set to 64MB, and there are 3 immutable memtables with sizes of 20, 30, 30. Although the total memory usage is 80MB > 64MB, dropping the oldest memtable will reduce the memory usage to 60MB < 64MB, so in this case no memtable will be dropped.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5022
Differential Revision: D14394062
Pulled By: miasantreble
fbshipit-source-id: 60457a509c6af89d0993f988c9b5c2aa9e45f5c5
Summary:
The batched MultiGet() implementation was not correctly handling bloom filter lookups when whole_key_filtering is disabled. It was incorrectly skipping keys not in the prefix_extractor domain, and not calling transform for keys in domain. This PR fixes both problems by moving the domain check and transformation to the FilterBlockReader.
Tests:
Unit test (confirmed failed before the fix)
make check
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5665
Differential Revision: D16902380
Pulled By: anand1976
fbshipit-source-id: a6be81ad68a6e37134a65246aec7a2c590eccf00
Summary:
The comments of snap_refresh_nanos advertise that the snapshot refresh feature will be disabled when the option is set to 0. This contract is however not honored in the code: https://github.com/facebook/rocksdb/pull/5278
The patch fixes that and also adds an assert to ensure that the feature is not used when the option is zero.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5724
Differential Revision: D16918185
Pulled By: maysamyabandeh
fbshipit-source-id: fec167287df7d85093e087fc39c0eb243e3bbd7e
Summary:
Recently readahead is introduced for checksum verifying. However, users cannot override the setting for the checksum verifying before external SST file ingestion. Introduce a new option for the purpose.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5721
Test Plan: Add a new unit test for it.
Differential Revision: D16906896
fbshipit-source-id: 218ec37001ddcc05411cefddbe233d15ab308476
Summary:
Right now VerifyChecksum() doesn't do read-ahead. In some use cases, users won't be able to achieve good performance. With this change, by default, RocksDB will do a default readahead, and users will be able to overwrite the readahead size by passing in a ReadOptions.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5713
Test Plan: Add a new unit test.
Differential Revision: D16860874
fbshipit-source-id: 0cff0fe79ac855d3d068e6ccd770770854a68413
Summary:
Update HISTORY.md by removing a feature from "Unreleased" to 6.4.0 after cherry-picking related commits to 6.4.fb branch.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5714
Differential Revision: D16865334
Pulled By: riversand963
fbshipit-source-id: f17ede905a1dfbbcdf98806ca398c618cf54748a
Summary:
Add a command in ldb so that users can print out tombstones in SST files.
In order to test the code, change the interface of LDBCommandRunner::RunCommand() so that it doesn't return from the program, but return the status code.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5615
Test Plan: Add a new unit test
Differential Revision: D16550326
fbshipit-source-id: 88ddfe6984bdcbb3a528abdd115089df09eba52e
Summary:
Most existing RocksDB unit tests run on `Env::Default()`. It will be useful to port the unit tests to non-default environments, e.g. `HdfsEnv`, etc.
This pull request is one step towards this goal. If RocksDB unit tests are built with a static library exposing a function `RegisterCustomObjects()`, then it is possible to implement custom object registrar logic in the library. RocksDB unit test can call `RegisterCustomObjects()` at the beginning.
By default, `ROCKSDB_UNITTESTS_WITH_CUSTOM_OBJECTS_FROM_STATIC_LIBS` is not defined, thus this PR has no impact on existing RocksDB because `RegisterCustomObjects()` is a noop.
Test plan (on devserver):
```
$make clean && COMPILE_WITH_ASAN=1 make -j32 all
$make check
```
All unit tests must pass.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5676
Differential Revision: D16679157
Pulled By: riversand963
fbshipit-source-id: aca571af3fd0525277cdc674248d0fe06e060f9d
Summary:
In some cases, we don't have to get really accurate number. Something like 10% off is fine, we can create a new option for that use case. In this case, we can calculate size for full files first, and avoid estimation inside SST files if full files got us a huge number. For example, if we already covered 100GB of data, we should be able to skip partial dives into 10 SST files of 30MB.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5609
Differential Revision: D16433481
Pulled By: elipoz
fbshipit-source-id: 5830b31e1c656d0fd3a00d7fd2678ddc8f6e601b
Summary:
Master branch had been left at 6.2 and history of 6.3 and beyond were merged. Updated this to correct.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5652
Differential Revision: D16570498
Pulled By: gfosco
fbshipit-source-id: 79f62ec570539a3e3d7d7c84a6cf7b722395fafe
Summary:
The new DB::GetApproximateSizes with SizeApproximationOptions argument, which allows to add more options/knobs to the DB::GetApproximateSizes call (beyond only the include_flags)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5626
Differential Revision: D16496913
Pulled By: elipoz
fbshipit-source-id: ee8c6c182330a285fa056ecfc3905a592b451720
Summary:
The ObjectRegistry class replaces the Registrar and NewCustomObjects. Objects are registered with the registry by Type (the class must implement the static const char *Type() method).
This change is necessary for a few reasons:
- By having a class (rather than static template instances), the class can be passed between compilation units, meaning that objects could be registered and shared from a dynamic library with an executable.
- By having a class with instances, different units could have different objects registered. This could be useful if, for example, one Option allowed for a dynamic library and one did not.
When combined with some other PRs (being able to load shared libraries, a Configurable interface to configure objects to/from string), this code will allow objects in external shared libraries to be added to a RocksDB image at run-time, rather than requiring every new extension to be built into the main library and called explicitly by every program.
Test plan (on riversand963's devserver)
```
$COMPILE_WITH_ASAN=1 make -j32 all && sleep 1 && make check
```
All tests pass.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5293
Differential Revision: D16363396
Pulled By: riversand963
fbshipit-source-id: fbe4acb615bfc11103eef40a0b288845791c0180
Summary:
RocksDB has historically stored uncompression dictionary objects in the block
cache as opposed to storing just the block contents. This neccesitated
evicting the object upon table close. With the new code, only the raw blocks
are stored in the cache, eliminating the need for eviction.
In addition, the patch makes the following improvements:
1) Compression dictionary blocks are now prefetched/pinned similarly to
index/filter blocks.
2) A copy operation got eliminated when the uncompression dictionary is
retrieved.
3) Errors related to retrieving the uncompression dictionary are propagated as
opposed to silently ignored.
Note: the patch temporarily breaks the compression dictionary evicition stats.
They will be fixed in a separate phase.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5584
Test Plan: make asan_check
Differential Revision: D16344151
Pulled By: ltamasi
fbshipit-source-id: 2962b295f5b19628f9da88a3fcebbce5a5017a7b
Summary:
Right now, ldb cannot scan a DB with merge operands with default ldb. There is no hard to give a general merge operator so that it can at least print out something
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5607
Test Plan: Run ldb against a DB with merge operands and see the outputs.
Differential Revision: D16442634
fbshipit-source-id: c66c414ec07f219cfc6e6ec2cc14c783ee95df54
Summary:
There are concerns about the correctness of this patch. Disabling by default until the concerns are resolved.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5606
Differential Revision: D16428064
Pulled By: maysamyabandeh
fbshipit-source-id: a89280f0ea85796c9c9dfbfd9a8e91dad9b000b3
Summary:
Right now, users cannot take advantage of row cache, unless no snapshot is used, or Get() is repeated for the same snapshots. This limits the usage of row cache.
This change eliminate this restriction in some cases. If the snapshot used is newer than the largest sequence number in the file, and write callback function is not registered, the same row cache key is used as no snapshot is given. We still need the callback function restriction for now because the callback function may filter out different keys for different snapshots even if the snapshots are new.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5600
Test Plan: Add a unit test.
Differential Revision: D16386616
fbshipit-source-id: 6b7d214bd215d191b03ccf55926ad4b703ec2e53
Summary:
Currently, when the block cache is used for the filter block, it is not
really the block itself that is stored in the cache but a FilterBlockReader
object. Since this object is not pure data (it has, for instance, pointers that
might dangle, including in one case a back pointer to the TableReader), it's not
really sharable. To avoid the issues around this, the current code erases the
cache entries when the TableReader is closed (which, BTW, is not sufficient
since a concurrent TableReader might have picked up the object in the meantime).
Instead of doing this, the patch moves the FilterBlockReader out of the cache
altogether, and decouples the filter reader object from the filter block.
In particular, instead of the TableReader owning, or caching/pinning the
FilterBlockReader (based on the customer's settings), with the change the
TableReader unconditionally owns the FilterBlockReader, which in turn
owns/caches/pins the filter block. This change also enables us to reuse the code
paths historically used for data blocks for filters as well.
Note:
Eviction statistics for filter blocks are temporarily broken. We plan to fix this in a
separate phase.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5504
Test Plan: make asan_check
Differential Revision: D16036974
Pulled By: ltamasi
fbshipit-source-id: 770f543c5fb4ed126fd1e04bfd3809cf4ff9c091
Summary:
Right now ldb can open running DB through read-only DB. However, it might leave info logs files to the read-only DB directory. Add an option to open the DB as secondary to avoid it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5537
Test Plan:
Run
./ldb scan --max_keys=10 --db=/tmp/rocksdbtest-2491/dbbench --secondary_path=/tmp --no_value --hex
and
./ldb get 0x00000000000000103030303030303030 --hex --db=/tmp/rocksdbtest-2491/dbbench --secondary_path=/tmp
against a normal db_bench run and observe the output changes. Also observe that no new info logs files are created under /tmp/rocksdbtest-2491/dbbench.
Run without --secondary_path and observe that new info logs created under /tmp/rocksdbtest-2491/dbbench.
Differential Revision: D16113886
fbshipit-source-id: 4e09dec47c2528f6ca08a9e7a7894ba2d9daebbb
Summary:
Previously `GetAllKeyVersions()` supports default column family only. This PR add support for other column families.
Test plan (devserver):
```
$make clean && COMPILE_WITH_ASAN=1 make -j32 db_basic_test
$./db_basic_test --gtest_filter=DBBasicTest.GetAllKeyVersions
```
All other unit tests must pass.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5544
Differential Revision: D16147551
Pulled By: riversand963
fbshipit-source-id: 5a61aece2a32d789e150226a9b8d53f4a5760168
Summary:
1. Cleanup WAL trash files on open
2. Don't apply deletion rate limit if WAL dir is different from db dir
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5520
Test Plan: Add new unit tests and make check
Differential Revision: D16096750
Pulled By: anand1976
fbshipit-source-id: 6f07858ad864b754b711db416f0389c45ede599b
Summary:
Sometimes it is helpful to fetch the whole history of stats after benchmark runs. Add such an option
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5532
Test Plan: Run the benchmark manually and observe the output is as expected.
Differential Revision: D16097764
fbshipit-source-id: 10b5b735a22a18be198b8f348be11f11f8806904
Summary:
Enhancement to MultiGet batching to read data blocks required for keys in a batch in parallel from disk. It uses Env::MultiRead() API to read multiple blocks and reduce latency.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5464
Test Plan:
1. make check
2. make asan_check
3. make asan_crash
Differential Revision: D15911771
Pulled By: anand1976
fbshipit-source-id: 605036b9af0f90ca0020dc87c3a86b4da6e83394
Summary:
Mid-point insertion is a useful feature and is mature now. Make it default. Also changed cache_index_and_filter_blocks_with_high_priority=true as default accordingly, so that we won't evict index and filter blocks easier after the change, to avoid too many surprises to users.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5508
Test Plan: Run all existing tests.
Differential Revision: D16021179
fbshipit-source-id: ce8456e8d43b3bfb48df6c304b5290a9d19817eb
Summary:
Add C binding for secondary instance as well as unit test.
Test plan (on devserver)
```
$make clean && COMPILE_WITH_ASAN=1 make -j20 all
$./c_test
$make check
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5505
Differential Revision: D16000043
Pulled By: riversand963
fbshipit-source-id: 3361ef6bfdf4ce12438cee7290a0ac203b5250bd
Summary:
The first key is used to defer reading the data block until this file gets to the top of merging iterator's heap. For short range scans, most files never make it to the top of the heap, so this change can reduce read amplification by a lot sometimes.
Consider the following workload. There are a few data streams (we'll be calling them "logs"), each stream consisting of a sequence of blobs (we'll be calling them "records"). Each record is identified by log ID and a sequence number within the log. RocksDB key is concatenation of log ID and sequence number (big endian). Reads are mostly relatively short range scans, each within a single log. Writes are mostly sequential for each log, but writes to different logs are randomly interleaved. Compactions are disabled; instead, when we accumulate a few tens of sst files, we create a new column family and start writing to it.
So, a typical sst file consists of a few ranges of blocks, each range corresponding to one log ID (we use FlushBlockPolicy to cut blocks at log boundaries). A typical read would go like this. First, iterator Seek() reads one block from each sst file. Then a series of Next()s move through one sst file (since writes to each log are mostly sequential) until the subiterator reaches the end of this log in this sst file; then Next() switches to the next sst file and reads sequentially from that, and so on. Often a range scan will only return records from a small number of blocks in small number of sst files; in this case, the cost of initial Seek() reading one block from each file may be bigger than the cost of reading the actually useful blocks.
Neither iterate_upper_bound nor bloom filters can prevent reading one block from each file in Seek(). But this PR can: if the index contains first key from each block, we don't have to read the block until this block actually makes it to the top of merging iterator's heap, so for short range scans we won't read any blocks from most of the sst files.
This PR does the deferred block loading inside value() call. This is not ideal: there's no good way to report an IO error from inside value(). As discussed with siying offline, it would probably be better to change InternalIterator's interface to explicitly fetch deferred value and get status. I'll do it in a separate PR.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5289
Differential Revision: D15256423
Pulled By: al13n321
fbshipit-source-id: 750e4c39ce88e8d41662f701cf6275d9388ba46a
Summary:
It it not safe to assume application had sync the SST file before ingest it into DB. Also the directory to put the ingested file needs to be fsync, otherwise the file can be lost. For integrity of RocksDB we need to sync the ingested file and directory before apply the change to manifest.
Also syncing after writing global sequence when write_global_seqno=true was removed in https://github.com/facebook/rocksdb/issues/4172. Adding it back.
Fixes https://github.com/facebook/rocksdb/issues/5287.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5435
Test Plan:
Test ingest file with ldb command and observe fsync/fdatasync in strace output. Tried both move_files=true and move_files=false.
https://gist.github.com/yiwu-arbug/650a4023f57979056d83485fa863bef9
More test suggestions are welcome.
Differential Revision: D15941675
Pulled By: riversand963
fbshipit-source-id: 389533f3923065a96df2cdde23ff4724a1810d78
Summary:
When tailing the WAL with TransactionLogIterator, it used to return Corruption status to indicate that the WAL has new tail that is not visible to the iterator, which is a misleading status. The patch replaces it with TryAgain which is more descriptive of a status, indicating that the user needs to create a new iterator to fetch the recent tail.
Fixes https://github.com/facebook/rocksdb/issues/5455
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5474
Differential Revision: D15898953
Pulled By: maysamyabandeh
fbshipit-source-id: 40966f6457cb539e1aeb104daeada6b0e46059fc
Summary:
The patch brings the semantics of per-block-type read performance
context counters in sync with the generic block_read_count by only
incrementing the counter if the block was actually read from the file.
It also fixes index_block_read_count, which fell victim to the
refactoring in PR https://github.com/facebook/rocksdb/issues/5298.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5484
Test Plan: Extended the unit tests.
Differential Revision: D15887431
Pulled By: ltamasi
fbshipit-source-id: a3889759d0ac5759d56625d692cd828d1b9207a6
Summary:
While the secondary is replaying after the primary, the primary may switch to a new MANIFEST. The secondary is already able to detect and follow the primary to the new MANIFEST. However, the current implementation has a bug, described as follows.
The new MANIFEST's first records have been generated by VersionSet::WriteSnapshot to describe the current state of the column families and the db as of the MANIFEST creation. Since the secondary instance has already finished recovering upon start, there is no need for the secondary to process these records. Actually, if the secondary were to replay these records, the secondary may end up adding the same SST files **again** to each column family, causing consistency checks done by VersionBuilder to fail. Therefore, we record the number of records to skip at the beginning of the new MANIFEST and ignore them.
Test plan (on dev server)
```
$make clean && make -j32 all
$./db_secondary_test
```
All existing unit tests must pass as well.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5472
Differential Revision: D15866771
Pulled By: riversand963
fbshipit-source-id: a1eec4837fb2ad13059398efb0f437e74fd53bed
Summary:
It seems like CF Options are not properly validated when creating a new column family with `CreateColumnFamily` API; only a selected few checks are done. Calling `ColumnFamilyData::ValidateOptions`, which is the single source for all CFOptions validations, will help fix this. (`ColumnFamilyData::ValidateOptions` is already called at the time of `DB::Open`).
**Test Plan:**
Added a new test: `DBTest.CreateColumnFamilyShouldFailOnIncompatibleOptions`
```
TEST_TMPDIR=/dev/shm ./db_test --gtest_filter=DBTest.CreateColumnFamilyShouldFailOnIncompatibleOptions
```
Also ran gtest-parallel to make sure the new test is not flaky.
```
TEST_TMPDIR=/dev/shm ~/gtest-parallel/gtest-parallel ./db_test --gtest_filter=DBTest.CreateColumnFamilyShouldFailOnIncompatibleOptions --repeat=10000
[10000/10000] DBTest.CreateColumnFamilyShouldFailOnIncompatibleOptions (15 ms)
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5453
Differential Revision: D15816851
Pulled By: sagar0
fbshipit-source-id: 9e702b9850f5c4a7e0ef8d39e1e6f9b81e7fe1e5
Summary:
In regular RocksDB instance, `MemTable::earliest_seqno_` is "db sequence number at the time of creation". However, we cannot use the db sequence number to set the value of `MemTable::earliest_seqno_` for secondary instance, i.e. `DBImplSecondary` due to the logic of MANIFEST and WAL replay.
When replaying the log files of the primary, the secondary instance first replays MANIFEST and updates the db sequence number if necessary. Next, the secondary replays WAL files, creates new memtables if necessary and inserts key-value pairs into memtables. The following can occur when the db has two or more column families.
Assume the db has column family "default" and "cf1". At a certain in time, both "default" and "cf1" have data in memtables.
1. Primary triggers a flush and flushes "cf1". "default" is **not** flushed.
2. Secondary replays the MANIFEST updates its db sequence number to the latest value learned from the MANIFEST.
3. Secondary starts to replay WAL that contains the writes to "default". It is possible that the write batches' sequence numbers are smaller than the db sequence number. In this case, these write batches will be skipped, and these updates will not be visible to reader until "default" is later flushed.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5413
Differential Revision: D15637407
Pulled By: riversand963
fbshipit-source-id: 3de3fe35cfc6f1b9f844f3f926f0df29717b6580
Summary:
The patch cleans up the handling of cache hit/miss/insertion related
performance counters, get context counters, and statistics by
eliminating some code duplication and factoring out the affected logic
into separate methods. In addition, it makes the semantics of cache hit
metrics more consistent by changing the code so that accessing a
partition of partitioned indexes/filters through a pinned reference no
longer counts as a cache hit.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5408
Differential Revision: D15610883
Pulled By: ltamasi
fbshipit-source-id: ee749c18965077aca971d8f8bee8b24ed8fa76f1
Summary:
It's useful to be able to (optionally) associate key-value pairs with user-provided timestamps. This PR is an early effort towards this goal and continues the work of facebook#4942. A suite of new unit tests exist in DBBasicTestWithTimestampWithParam. Support for timestamp requires the user to provide timestamp as a slice in `ReadOptions` and `WriteOptions`. All timestamps of the same database must share the same length, format, etc. The format of the timestamp is the same throughout the same database, and the user is responsible for providing a comparator function (Comparator) to order the <key, timestamp> tuples. Once created, the format and length of the timestamp cannot change (at least for now).
Test plan (on devserver):
```
$COMPILE_WITH_ASAN=1 make -j32 all
$./db_basic_test --gtest_filter=Timestamp/DBBasicTestWithTimestampWithParam.PutAndGet/*
$make check
```
All tests must pass.
We also run the following db_bench tests to verify whether there is regression on Get/Put while timestamp is not enabled.
```
$TEST_TMPDIR=/dev/shm ./db_bench -benchmarks=fillseq,readrandom -num=1000000
$TEST_TMPDIR=/dev/shm ./db_bench -benchmarks=fillrandom -num=1000000
```
Repeat for 6 times for both versions.
Results are as follows:
```
| | readrandom | fillrandom |
| master | 16.77 MB/s | 47.05 MB/s |
| PR5079 | 16.44 MB/s | 47.03 MB/s |
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5079
Differential Revision: D15132946
Pulled By: riversand963
fbshipit-source-id: 833a0d657eac21182f0f206c910a6438154c742c
Summary:
Flush/compaction use `MergeUntil` which has a special code path to
handle a merge ending with a non-`Merge` point key. In particular if
that key is a `Put` we forgot to check whether it is covered by a range
tombstone. If it is covered then we must not include it in the following call
to `TimedFullMerge`.
Fixes#5392.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5406
Differential Revision: D15611144
Pulled By: sagar0
fbshipit-source-id: ba6a7863ca2d043f591de78fd0c4f4561f0c500e
Summary:
Right now, with auto roll logger, options.keep_log_file_num enforcement is triggered by events like DB reopen or full obsolete scan happens. In the mean time, the size and number of log files can grow without a limit. We put a stronger enforcement to the option, so that the number of log files can always under control.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5370
Differential Revision: D15570413
Pulled By: siying
fbshipit-source-id: 0916c3c4d42ab8fdd29389ee7fd7e1557b03176e
Summary:
1. Fix a bug in WAL replay in which write batches with old sequence numbers are mistakenly inserted into memtables.
2. Add support for benchmarking secondary instance to db_bench_tool.
With changes made in this PR, we can start benchmarking secondary instance
using two processes. It is also possible to vary the frequency at which the
secondary instance tries to catch up with the primary. The info log of the
secondary can be found in a directory whose path can be specified with
'-secondary_path'.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5170
Differential Revision: D15564608
Pulled By: riversand963
fbshipit-source-id: ce97688ed3d33f69d3a0b9266ebbbbf887aa0ec8
Summary:
Currently, when the block cache is used for index blocks as well, it is
not really the index block that is stored in the cache but an
IndexReader object. Since this object is not pure data (it has, for
instance, pointers that might dangle), it's not really sharable. To
avoid the issues around this, the current code uses a dummy unique cache
key for each TableReader to store the IndexReader, and erases the
IndexReader entry when the TableReader is closed. Instead of doing this,
the new code moves the IndexReader out of the cache altogether. In
particular, instead of the TableReader owning, or caching/pinning the
IndexReader based on the customer's settings, the TableReader
unconditionally owns the IndexReader, which in turn owns/caches/pins
the index block (which is itself sharable and thus can be safely put in
the cache without any hacks).
Note: the change has two side effects:
1) Partitions of partitioned indexes no longer affect the read
amplification statistics.
2) Eviction statistics for index blocks are temporarily broken. We plan to fix
this in a separate phase.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5298
Differential Revision: D15303203
Pulled By: ltamasi
fbshipit-source-id: 935a69ba59d87d5e44f42e2310619b790c366e47
Maysam Yabandeh