Summary:
The main challenge to make the memtable garbage collection prototype (nicknamed `mempurge`) was to not get rid of WAL files that contain unflushed (but mempurged) data. That was successfully guaranteed by not writing the VersionEdit to the MANIFEST file after a successful mempurge.
By not writing VersionEdits to the `MANIFEST` file after a succesful mempurge operation, we do not change the earliest log file number that contains unflushed data: `cfd->GetLogNumber()` (`cfd->SetLogNumber()` is only called in `VersionSet::ProcessManifestWrites`). As a result, a number of functions introduced earlier just for the mempurge operation are not obscolete/redundant. (e.g.: `FlushJob::ExtractEarliestLogFileNumber`), and this PR aims at cleaning up all these now-unnecessary functions. In particular, we no longer need to store the earliest log file number in the `MemTable` struct itself. This PR therefore also reverts the `MemTable` struct to its original form.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8558
Test Plan: Already included in `db_flush_test.cc`.
Reviewed By: anand1976
Differential Revision: D29764351
Pulled By: bjlemaire
fbshipit-source-id: 0f43b260fa270251862512f397d3f24ee62e8437
Summary:
In this PR, `mempurge` is made compatible with the Write Ahead Log: in case of recovery, the DB is now capable of recovering the data that was "mempurged" and kept in the `imm()` list of immutable memtables.
The twist was to add a uint64_t to the `memtable` struct to store the number of the earliest log file containing entries from the `memtable`. When a `Flush` operation is replaced with a `MemPurge`, the `VersionEdit` (which usually contains the new min log file number to pick up for recovery and the level 0 file path of the newly created SST file) is no longer appended to the manifest log, and every time the `deleteWal` method is called, a check is made on the list of immutable memtables.
This PR also includes a unit test that verifies that no data is lost upon Reopening of the database when the mempurge feature is activated. This extensive unit test includes two column families, with valid data contained in the imm() at time of "crash"/reopening (recovery).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8528
Reviewed By: pdillinger
Differential Revision: D29701097
Pulled By: bjlemaire
fbshipit-source-id: 072a900fb6ccc1edcf5eef6caf88f3060238edf9
Summary:
In https://github.com/facebook/rocksdb/issues/8454, I introduced a new process baptized `MemPurge` (memtable garbage collection). This new PR is built upon this past mempurge prototype.
In this PR, I made the `mempurge` process a background task, which provides superior performance since the mempurge process does not cling on the db_mutex anymore, and addresses severe restrictions from the past iteration (including a scenario where the past mempurge was failling, when a memtable was mempurged but was still referred to by an iterator/snapshot/...).
Now the mempurge process ressembles an in-memory compaction process: the stack of immutable memtables is filtered out, and the useful payload is used to populate an output memtable. If the output memtable is filled at more than 60% capacity (arbitrary heuristic) the mempurge process is aborted and a regular flush process takes place, else the output memtable is kept in the immutable memtable stack. Note that adding this output memtable to the `imm()` memtable stack does not trigger another flush process, so that the flush thread can go to sleep at the end of a successful mempurge.
MemPurge is activated by making the `experimental_allow_mempurge` flag `true`. When activated, the `MemPurge` process will always happen when the flush reason is `kWriteBufferFull`.
The 3 unit tests confirm that this process supports `Put`, `Get`, `Delete`, `DeleteRange` operators and is compatible with `Iterators` and `CompactionFilters`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8505
Reviewed By: pdillinger
Differential Revision: D29619283
Pulled By: bjlemaire
fbshipit-source-id: 8a99bee76b63a8211bff1a00e0ae32360aaece95
Summary:
Implement an experimental feature called "MemPurge", which consists in purging "garbage" bytes out of a memtable and reuse the memtable struct instead of making it immutable and eventually flushing its content to storage.
The prototype is by default deactivated and is not intended for use. It is intended for correctness and validation testing. At the moment, the "MemPurge" feature can be switched on by using the `options.experimental_allow_mempurge` flag. For this early stage, when the allow_mempurge flag is set to `true`, all the flush operations will be rerouted to perform a MemPurge. This is a temporary design decision that will give us the time to explore meaningful heuristics to use MemPurge at the right time for relevant workloads . Moreover, the current MemPurge operation only supports `Puts`, `Deletes`, `DeleteRange` operations, and handles `Iterators` as well as `CompactionFilter`s that are invoked at flush time .
Three unit tests are added to `db_flush_test.cc` to test if MemPurge works correctly (and checks that the previously mentioned operations are fully supported thoroughly tested).
One noticeable design decision is the timing of the MemPurge operation in the memtable workflow: for this prototype, the mempurge happens when the memtable is switched (and usually made immutable). This is an inefficient process because it implies that the entirety of the MemPurge operation happens while holding the db_mutex. Future commits will make the MemPurge operation a background task (akin to the regular flush operation) and aim at drastically enhancing the performance of this operation. The MemPurge is also not fully "WAL-compatible" yet, but when the WAL is full, or when the regular MemPurge operation fails (or when the purged memtable still needs to be flushed), a regular flush operation takes place. Later commits will also correct these behaviors.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8454
Reviewed By: anand1976
Differential Revision: D29433971
Pulled By: bjlemaire
fbshipit-source-id: 6af48213554e35048a7e03816955100a80a26dc5
Summary:
Currently, we either use the file system inode or a monotonically incrementing runtime ID as the block cache key prefix. However, if we use a monotonically incrementing runtime ID (in the case that the file system does not support inode id generation), in some cases, it cannot ensure uniqueness (e.g., we have secondary cache migrated from host to host). We use DbSessionID (20 bytes) + current file number (at most 10 bytes) as the new cache block key prefix when the secondary cache is enabled. So can accommodate scenarios such as transfer of cache state across hosts.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8360
Test Plan: add the test to lru_cache_test
Reviewed By: pdillinger
Differential Revision: D29006215
Pulled By: zhichao-cao
fbshipit-source-id: 6cff686b38d83904667a2bd39923cd030df16814
Summary:
This patch does two things:
1) Introduces some aliases in order to eliminate/prevent long-winded type names
w/r/t the internal table property collectors (see e.g.
`std::vector<std::unique_ptr<IntTblPropCollectorFactory>>`).
2) Makes it possible to apply only a subrange of table property collectors during
table building by turning `TableBuilderOptions::int_tbl_prop_collector_factories`
from a pointer to a `vector` into a range (i.e. a pair of iterators).
Rationale: I plan to introduce a BlobDB related table property collector, which
should only be applied during table creation if blob storage is enabled at the moment
(which can be changed dynamically). This change will make it possible to include/
exclude the BlobDB related collector as needed without having to introduce
a second `vector` of collectors in `ColumnFamilyData` with pretty much the same
contents.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8298
Test Plan: `make check`
Reviewed By: jay-zhuang
Differential Revision: D28430910
Pulled By: ltamasi
fbshipit-source-id: a81d28f2c59495865300f43deb2257d2e6977c8e
Summary:
Larger arena block size does provide the benefit of reducing allocation overhead, however it may cause other troubles. For example, allocator is more likely not to allocate them to physical memory and trigger page fault. Weighing the risk, we cap the arena block size to 1MB. Users can always use a larger value if they want.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7907
Test Plan: Run all existing tests
Reviewed By: pdillinger
Differential Revision: D26135269
fbshipit-source-id: b7f55afd03e6ee1d8715f90fa11b6c33944e9ea8
Summary:
The ImmutableCFOptions contained a bunch of fields that belonged to the ImmutableDBOptions. This change cleans that up by introducing an ImmutableOptions struct. Following the pattern of Options struct, this class inherits from the DB and CFOption structs (of the Immutable form).
Only one structural change (the ImmutableCFOptions::fs was changed to a shared_ptr from a raw one) is in this PR. All of the other changes involve moving the member variables from the ImmutableCFOptions into the ImmutableOptions and changing member variables or function parameters as required for compilation purposes.
Follow-on PRs may do a further clean-up of the code, such as renaming variables (such as "ImmutableOptions cf_options") and potentially eliminating un-needed function parameters (there is no longer a need to pass both an ImmutableDBOptions and an ImmutableOptions to a function).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8262
Reviewed By: pdillinger
Differential Revision: D28226540
Pulled By: mrambacher
fbshipit-source-id: 18ae71eadc879dedbe38b1eb8e6f9ff5c7147dbf
Summary:
Renaming ImmutableCFOptions::info_log and statistics to logger and stats. This is stage 2 in creating an ImmutableOptions class. It is necessary because the names match those in ImmutableOptions and have different types.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8227
Reviewed By: jay-zhuang
Differential Revision: D28000967
Pulled By: mrambacher
fbshipit-source-id: 3bf2aa04e8f1e8724d825b7deacf41080c14420b
Summary:
Resolves https://github.com/facebook/rocksdb/issues/8014
- Add an assertion on `DB::Open` to ensure `db_options.max_open_files` is unlimited if FIFO Compaction is being used.
- This is to align with what the docs mention and to prevent premature data deletion.
- Update tests to work with this assertion.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8172
Test Plan:
```bash
$ make check -j$(nproc)
Generated TARGETS Summary:
- 6 libs
- 0 binarys
- 180 tests
```
Reviewed By: ajkr
Differential Revision: D27768792
Pulled By: thejchap
fbshipit-source-id: cf6350535e3a3577fec72bcba75b3c094dc7a6f3
Summary:
For performance purposes, the lower level routines were changed to use a SystemClock* instead of a std::shared_ptr<SystemClock>. The shared ptr has some performance degradation on certain hardware classes.
For most of the system, there is no risk of the pointer being deleted/invalid because the shared_ptr will be stored elsewhere. For example, the ImmutableDBOptions stores the Env which has a std::shared_ptr<SystemClock> in it. The SystemClock* within the ImmutableDBOptions is essentially a "short cut" to gain access to this constant resource.
There were a few classes (PeriodicWorkScheduler?) where the "short cut" property did not hold. In those cases, the shared pointer was preserved.
Using db_bench readrandom perf_level=3 on my EC2 box, this change performed as well or better than 6.17:
6.17: readrandom : 28.046 micros/op 854902 ops/sec; 61.3 MB/s (355999 of 355999 found)
6.18: readrandom : 32.615 micros/op 735306 ops/sec; 52.7 MB/s (290999 of 290999 found)
PR: readrandom : 27.500 micros/op 871909 ops/sec; 62.5 MB/s (367999 of 367999 found)
(Note that the times for 6.18 are prior to revert of the SystemClock).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8033
Reviewed By: pdillinger
Differential Revision: D27014563
Pulled By: mrambacher
fbshipit-source-id: ad0459eba03182e454391b5926bf5cdd45657b67
Summary:
This PR
- adds a class `ManifestTailer` that inherits from `VersionEditHandlerPointInTime`. `ManifestTailer::Iterate()` can be called multiple times to tail the primary instance's MANIFEST and apply the changes to the secondary,
- updates the implementation of `ReactiveVersionSet::ReadAndApply` to use this class,
- removes unused code in version_set.cc,
- updates existing tests, e.g. removing deleted sync points from unit tests,
- adds a new test to address the bug in https://github.com/facebook/rocksdb/issues/7815.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7998
Test Plan:
make check
Existing and newly-added tests in version_set_test.cc and db_secondary_test.cc
Reviewed By: jay-zhuang
Differential Revision: D26926641
Pulled By: riversand963
fbshipit-source-id: 8d4dd15db0ba863c213f743e33b5a207e948c980
Summary:
## 1. Bug description:
When RocksDB Checkpoint, it may be stuck in `WaitUntilFlushWouldNotStallWrites` method.
## 2. Simple analysis of the reasons:
### 2.1 Configuration parameters:
```yaml
Compaction Style : Universal
max_write_buffer_number : 4
min_write_buffer_number_to_merge : 3
```
Checkpoint is usually very fast. When the Checkpoint is executed, `WaitUntilFlushWouldNotStallWrites` is called. If there are 2 Immutable MemTables, which are less than `min_write_buffer_number_to_merge`, they will not be flushed. But will enter this code.
```c++
// method: GetWriteStallConditionAndCause
if (mutable_cf_options.max_write_buffer_number> 3 &&
num_unflushed_memtables >=
mutable_cf_options.max_write_buffer_number-1) {
return {WriteStallCondition::kDelayed, WriteStallCause::kMemtableLimit};
}
```
code link: fbed72f03c/db/column_family.cc (L847)
Checkpoint thought there was a FlushJob, but it didn't. So will always wait.
### 2.2 solution:
Increase the restriction: the `number of Immutable MemTable` >= `min_write_buffer_number_to_merge will wait`.
If there are other better solutions, you can correct me.
### 2.3 Code that can reproduce the problem:
https://github.com/1996fanrui/fanrui-learning/blob/flink-1.12/module-java/src/main/java/com/dream/rocksdb/RocksDBCheckpointStuck.java
## 3. Interesting point
This bug will be triggered only when `the number of sorted runs >= level0_file_num_compaction_trigger`.
Because there is a break in WaitUntilFlushWouldNotStallWrites.
```c++
if (cfd->imm()->NumNotFlushed() <
cfd->ioptions()->min_write_buffer_number_to_merge &&
vstorage->l0_delay_trigger_count() <
mutable_cf_options.level0_file_num_compaction_trigger) {
break;
}
```
code link: fbed72f03c/db/db_impl/db_impl_compaction_flush.cc (L1974)
Universal may have `l0_delay_trigger_count() >= level0_file_num_compaction_trigger`, so this bug is triggered.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7921
Reviewed By: jay-zhuang
Differential Revision: D26900559
Pulled By: ajkr
fbshipit-source-id: 133c1252dad7393753f04a47590b68c7d8e670df
Summary:
Added a "only_mutable_options" flag to the ConfigOptions. When set, the Configurable methods will only look at/update options that are marked as kMutable.
Fixed DB::SetOptions to allow for the update of any mutable TableFactory options. Fixes https://github.com/facebook/rocksdb/issues/7385.
Added tests for the new flag. Updated HISTORY.md
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7936
Reviewed By: akankshamahajan15
Differential Revision: D26389646
Pulled By: mrambacher
fbshipit-source-id: 6dc247f6e999fa2814059ebbd0af8face109fea0
Summary:
Add support for IOTracing in blob files
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7958
Test Plan:
Add a new test and checked manually the trace_file for blob
files being recorded during read and write.
Reviewed By: ltamasi
Differential Revision: D26415950
Pulled By: akankshamahajan15
fbshipit-source-id: 49c2859b3a4f8307e7cb69a92704403a4da46d44
Summary:
Introduces and uses a SystemClock class to RocksDB. This class contains the time-related functions of an Env and these functions can be redirected from the Env to the SystemClock.
Many of the places that used an Env (Timer, PerfStepTimer, RepeatableThread, RateLimiter, WriteController) for time-related functions have been changed to use SystemClock instead. There are likely more places that can be changed, but this is a start to show what can/should be done. Over time it would be nice to migrate most (if not all) of the uses of the time functions from the Env to the SystemClock.
There are several Env classes that implement these functions. Most of these have not been converted yet to SystemClock implementations; that will come in a subsequent PR. It would be good to unify many of the Mock Timer implementations, so that they behave similarly and be tested similarly (some override Sleep, some use a MockSleep, etc).
Additionally, this change will allow new methods to be introduced to the SystemClock (like https://github.com/facebook/rocksdb/issues/7101 WaitFor) in a consistent manner across a smaller number of classes.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7858
Reviewed By: pdillinger
Differential Revision: D26006406
Pulled By: mrambacher
fbshipit-source-id: ed10a8abbdab7ff2e23d69d85bd25b3e7e899e90
Summary:
Added "no-elide-constructors to the ASSERT_STATUS_CHECK builds. This flag gives more errors/warnings for some of the Status checks where an inner class checks a Status and later returns it. In this case, without the elide check on, the returned status may not have been checked in the caller, thereby bypassing the checked code.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7798
Reviewed By: jay-zhuang
Differential Revision: D25680451
Pulled By: pdillinger
fbshipit-source-id: c3f14ed9e2a13f0a8c54d839d5fb4d1fc1e93917
Summary:
Uncommon bug seen by ASAN with
ColumnFamilyTest.LiveIteratorWithDroppedColumnFamily, if the last two
references to a ColumnFamilyData are both SuperVersions (during
InstallSuperVersion). The fix is to use UnrefAndTryDelete even in
SuperVersion::Cleanup but with a parameter to avoid re-entering Cleanup
on the same SuperVersion being cleaned up.
ColumnFamilyData::Unref is considered unsafe so removed.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7749
Test Plan: ./column_family_test --gtest_filter=*LiveIter* --gtest_repeat=100
Reviewed By: jay-zhuang
Differential Revision: D25354304
Pulled By: pdillinger
fbshipit-source-id: e78f3a3f67c40013b8432f31d0da8bec55c5321c
Summary:
When 2 phase commit is enabled, if there are prepared data in a WAL, the WAL should be kept, the minimum log number for such a WAL is written to MANIFEST during flush. In atomic flush, such information is not written to MANIFEST.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7570
Test Plan: Added a new unit test `DBAtomicFlushTest.ManualFlushUnder2PC`, this test fails in atomic flush without this PR, after this PR, it succeeds.
Reviewed By: riversand963
Differential Revision: D24394222
Pulled By: cheng-chang
fbshipit-source-id: 60ce74b21b704804943be40c8de01b41269cf116
Summary:
The patch adds basic garbage collection support to the integrated BlobDB
implementation. Valid blobs residing in the oldest blob files are relocated
as they are encountered during compaction. The threshold that determines
which blob files qualify is computed based on the configuration option
`blob_garbage_collection_age_cutoff`, which was introduced in https://github.com/facebook/rocksdb/issues/7661 .
Once a blob is retrieved for the purposes of relocation, it passes through the
same logic that extracts large values to blob files in general. This means that
if, for instance, the size threshold for key-value separation (`min_blob_size`)
got changed or writing blob files got disabled altogether, it is possible for the
value to be moved back into the LSM tree. In particular, one way to re-inline
all blob values if needed would be to perform a full manual compaction with
`enable_blob_files` set to `false`, `enable_blob_garbage_collection` set to
`true`, and `blob_file_garbage_collection_age_cutoff` set to `1.0`.
Some TODOs that I plan to address in separate PRs:
1) We'll have to measure the amount of new garbage in each blob file and log
`BlobFileGarbage` entries as part of the compaction job's `VersionEdit`.
(For the time being, blob files are cleaned up solely based on the
`oldest_blob_file_number` relationships.)
2) When compression is used for blobs, the compression type hasn't changed,
and the blob still qualifies for being written to a blob file, we can simply copy
the compressed blob to the new file instead of going through decompression
and compression.
3) We need to update the formula for computing write amplification to account
for the amount of data read from blob files as part of GC.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7694
Test Plan: `make check`
Reviewed By: riversand963
Differential Revision: D25069663
Pulled By: ltamasi
fbshipit-source-id: bdfa8feb09afcf5bca3b4eba2ba72ce2f15cd06a
Summary:
Fixes Issue https://github.com/facebook/rocksdb/issues/7497
When allow_data_in_errors db_options is set, log error key details in `ParseInternalKey()`
Have fixed most of the calls. Have few TODOs still pending - because have to make more deeper changes to pass in the allow_data_in_errors flag. Will do those in a separate PR later.
Tests:
- make check
- some of the existing tests that exercise the "internal key too small" condition are: dbformat_test, cuckoo_table_builder_test
- some of the existing tests that exercise the corrupted key path are: corruption_test, merge_helper_test, compaction_iterator_test
Example of new status returns:
- Key too small - `Corrupted Key: Internal Key too small. Size=5`
- Corrupt key with allow_data_in_errors option set to false: `Corrupted Key: '<redacted>' seq:3, type:3`
- Corrupt key with allow_data_in_errors option set to true: `Corrupted Key: '61' seq:3, type:3`
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7515
Reviewed By: ajkr
Differential Revision: D24240264
Pulled By: ramvadiv
fbshipit-source-id: bc48f5d4475ac19d7713e16df37505b31aac42e7
Summary:
The patch adds blob file support to the `Get` API by extending `Version` so that
whenever a blob reference is read from a file, the blob is retrieved from the corresponding
blob file and passed back to the caller. (This is assuming the blob reference is valid
and the blob file is actually part of the given `Version`.) It also introduces a cache
of `BlobFileReader`s called `BlobFileCache` that enables sharing `BlobFileReader`s
between callers. `BlobFileCache` uses the same backing cache as `TableCache`, so
`max_open_files` (if specified) limits the total number of open (table + blob) files.
TODO: proactively open/cache blob files and pin the cache handles of the readers in the
metadata objects similarly to what `VersionBuilder::LoadTableHandlers` does for
table files.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7540
Test Plan: `make check`
Reviewed By: riversand963
Differential Revision: D24260219
Pulled By: ltamasi
fbshipit-source-id: a8a2a4f11d3d04d6082201b52184bc4d7b0857ba
Summary:
Fix few test cases and add them in ASSERT_STATUS_CHECKED build.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7427
Test Plan:
1. ASSERT_STATUS_CHECKED=1 make -j48 check,
2. travis build for ASSERT_STATUS_CHECKED,
3. Without ASSERT_STATUS_CHECKED: make check -j64, CircleCI build and travis build
Reviewed By: pdillinger
Differential Revision: D23909983
Pulled By: akankshamahajan15
fbshipit-source-id: 42d7e4aea972acb9fcddb7ca73fcb82f93272434
Summary:
This PR merges the functionality of making the ColumnFamilyOptions, TableFactory, and DBOptions into Configurable into a single PR, resolving any merge conflicts
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5753
Reviewed By: ajkr
Differential Revision: D23385030
Pulled By: zhichao-cao
fbshipit-source-id: 8b977a7731556230b9b8c5a081b98e49ee4f160a
Summary:
Replace FSRandomAccessFile pointer with FSRandomAccessFilePtr
object in RandomAccessFileReader.
This new object wraps FSRandomAccessFile pointer.
Objective: If tracing is enabled, FSRandomAccessFile Ptr returns
FSRandomAccessFileTracingWrapper pointer that includes all necessary
information in IORecord and calls underlying FileSystem and invokes
IOTracer to dump that record in a binary file. If tracing is disabled
then, underlying FileSystem pointer is returned directly.
FSRandomAccessFilePtr wrapper class is added to bypass the FSRandomAccessFileWrapper when
tracing is disabled.
Test Plan: make check -j64
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7192
Reviewed By: anand1976
Differential Revision: D23356867
Pulled By: akankshamahajan15
fbshipit-source-id: 48f31168166a17a7444b40be44a9a9d4a5c7182c
Summary:
After releasing a snapshot, it checks whether it is suitable to trigger bottom compactions.
When disabling auto compactions, it may still schedule compaction when releasing a snapshot. Whereas no compaction job will be actually handled, so the state of LSM is not changed and compaction will be triggered again and again every time releasing a snapshot.
Too frequent compactions lead to high CPU usage and high db_mutex lock contention which affects foreground write duration finally.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7267
Test Plan:
- make check
- manual test
Reviewed By: akankshamahajan15
Differential Revision: D23252880
Pulled By: ajkr
fbshipit-source-id: 4431e071a35d9912a2a3592875db27bae521434b
Summary:
There are situations when RocksDB tries to recover, but the db is in an inconsistent state due to SST files referenced in the MANIFEST being missing. In this case, previous RocksDB will just fail the recovery and return a non-ok status.
This PR enables another possibility. During recovery, RocksDB checks possible MANIFEST files, and try to recover to the most recent state without missing table file. `VersionSet::Recover()` applies version edits incrementally and "materializes" a version only when this version does not reference any missing table file. After processing the entire MANIFEST, the version created last will be the latest version.
`DBImpl::Recover()` calls `VersionSet::Recover()`. Afterwards, WAL replay will *not* be performed.
To use this capability, set `options.best_efforts_recovery = true` when opening the db. Best-efforts recovery is currently incompatible with atomic flush.
Test plan (on devserver):
```
$make check
$COMPILE_WITH_ASAN=1 make all && make check
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6334
Reviewed By: anand1976
Differential Revision: D19778960
Pulled By: riversand963
fbshipit-source-id: c27ea80f29bc952e7d3311ecf5ee9c54393b40a8
Summary:
In Linux, when reopening DB with many SST files, profiling shows that 100% system cpu time spent for a couple of seconds for `GetLogicalBufferSize`. This slows down MyRocks' recovery time when site is down.
This PR introduces two new APIs:
1. `Env::RegisterDbPaths` and `Env::UnregisterDbPaths` lets `DB` tell the env when it starts or stops using its database directories . The `PosixFileSystem` takes this opportunity to set up a cache from database directories to the corresponding logical block sizes.
2. `LogicalBlockSizeCache` is defined only for OS_LINUX to cache the logical block sizes.
Other modifications:
1. rename `logical buffer size` to `logical block size` to be consistent with Linux terms.
2. declare `GetLogicalBlockSize` in `PosixHelper` to expose it to `PosixFileSystem`.
3. change the functions `IOError` and `IOStatus` in `env/io_posix.h` to have external linkage since they are used in other translation units too.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6457
Test Plan:
1. A new unit test is added for `LogicalBlockSizeCache` in `env/io_posix_test.cc`.
2. A new integration test is added for `DB` operations related to the cache in `db/db_logical_block_size_cache_test.cc`.
`make check`
Differential Revision: D20131243
Pulled By: cheng-chang
fbshipit-source-id: 3077c50f8065c0bffb544d8f49fb10bba9408d04
Summary:
In the current code base, we can use Directory from Env to manage directory (e.g, Fsync()). The PR https://github.com/facebook/rocksdb/issues/5761 introduce the File System as a new Env API. So we further replace the Directory class in DB with FSDirectory such that we can have more IO information from IOStatus returned by FSDirectory.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6468
Test Plan: pass make asan_check
Differential Revision: D20195261
Pulled By: zhichao-cao
fbshipit-source-id: 93962cb9436852bfcfb76e086d9e7babd461cbe1
Summary:
When dynamically linking two binaries together, different builds of RocksDB from two sources might cause errors. To provide a tool for user to solve the problem, the RocksDB namespace is changed to a flag which can be overridden in build time.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6433
Test Plan: Build release, all and jtest. Try to build with ROCKSDB_NAMESPACE with another flag.
Differential Revision: D19977691
fbshipit-source-id: aa7f2d0972e1c31d75339ac48478f34f6cfcfb3e
Summary:
A relatively recent regression causes for every CF, create and open directory is called for the DB directory, unless CF has a private directory. This doesn't scale well with large number of column families.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6358
Test Plan: Run all existing tests and see it pass. strace with db_bench --num_column_families and observe it doesn't open directory for number of column families.
Differential Revision: D19675141
fbshipit-source-id: da01d9216f1dae3f03d4064fbd88ce71245bd9be
Summary:
unordered_write is incompatible with non-zero max_successive_merges. Although we check this at runtime, we currently don't prevent the user from setting this combination in options. This has led to stress tests to fail with this combination is tried in ::SetOptions.
The patch fixes that and also reverts the changes performed by https://github.com/facebook/rocksdb/pull/6254, in which max_successive_merges was mistakenly declared incompatible with unordered_write.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6284
Differential Revision: D19356115
Pulled By: maysamyabandeh
fbshipit-source-id: f06dadec777622bd75f267361c022735cf8cecb6
Summary:
allow_concurrent_memtable_write is incompatible with non-zero max_successive_merges. Although we check this at runtime, we currently don't prevent the user from setting this combination in options. This has led to stress tests to fail with this combination is tried in ::SetOptions. The patch fixes that.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6254
Differential Revision: D19265819
Pulled By: maysamyabandeh
fbshipit-source-id: 47f2e2dc26fe0972c7152f4da15dadb9703f1179
Summary:
level passed into ColumnFamilyData::CalculateSSTWriteHint() can be smaller than base_level in current version, which would cause overflow.
We see ubsan complains:
db/compaction/compaction_job.cc:1511:39: runtime error: load of value 4294967295, which is not a valid value for type 'Env::WriteLifeTimeHint'
and I hope this commit fixes it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6212
Test Plan: Run existing tests and see them to pass.
Differential Revision: D19168442
fbshipit-source-id: bf8fd86f85478ecfa7556db46dc3242de8c83dc9
Summary:
I found that CleanupSuperVersion() may block Get() for 30ms+ （per MemTable is 256MB）.
Then I found "delete sv" in ~SuperVersion() takes the time.
The backtrace looks like this
DBImpl::GetImpl() -> DBImpl::ReturnAndCleanupSuperVersion() ->
DBImpl::CleanupSuperVersion() : delete sv; -> ~SuperVersion()
I think it's better to delete in a background thread, please review it。
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6146
Differential Revision: D18972066
fbshipit-source-id: 0f7b0b70b9bb1e27ad6fc1c8a408fbbf237ae08c
Summary:
The current Env API encompasses both storage/file operations, as well as OS related operations. Most of the APIs return a Status, which does not have enough metadata about an error, such as whether its retry-able or not, scope (i.e fault domain) of the error etc., that may be required in order to properly handle a storage error. The file APIs also do not provide enough control over the IO SLA, such as timeout, prioritization, hinting about placement and redundancy etc.
This PR separates out the file/storage APIs from Env into a new FileSystem class. The APIs are updated to return an IOStatus with metadata about the error, as well as to take an IOOptions structure as input in order to allow more control over the IO.
The user can set both ```options.env``` and ```options.file_system``` to specify that RocksDB should use the former for OS related operations and the latter for storage operations. Internally, a ```CompositeEnvWrapper``` has been introduced that inherits from ```Env``` and redirects individual methods to either an ```Env``` implementation or the ```FileSystem``` as appropriate. When options are sanitized during ```DB::Open```, ```options.env``` is replaced with a newly allocated ```CompositeEnvWrapper``` instance if both env and file_system have been specified. This way, the rest of the RocksDB code can continue to function as before.
This PR also ports PosixEnv to the new API by splitting it into two - PosixEnv and PosixFileSystem. PosixEnv is defined as a sub-class of CompositeEnvWrapper, and threading/time functions are overridden with Posix specific implementations in order to avoid an extra level of indirection.
The ```CompositeEnvWrapper``` translates ```IOStatus``` return code to ```Status```, and sets the severity to ```kSoftError``` if the io_status is retryable. The error handling code in RocksDB can then recover the DB automatically.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5761
Differential Revision: D18868376
Pulled By: anand1976
fbshipit-source-id: 39efe18a162ea746fabac6360ff529baba48486f
Summary:
It's easy to cause coredump when closing ColumnFamilyHandle with unreleased iterators, especially iterators release is controlled by java GC when using JNI.
This patch fixed concurrent CF iteration and drop, we let iterators(actually SuperVersion) hold a ColumnFamilyData reference to prevent the CF from being released too early.
fixed https://github.com/facebook/rocksdb/issues/5982
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6147
Differential Revision: D18926378
fbshipit-source-id: 1dff6d068c603d012b81446812368bfee95a5e15
Summary:
By default options.ttl is disabled. We believe a better default will be 30 days, which means deleted data the database will be removed from SST files slightly after 30 days, for most of the cases.
Make the default UINT64_MAX - 1 to indicate that it is not overridden by users.
Change periodic_compaction_seconds to be UINT64_MAX - 1 to UINT64_MAX too to be consistent. Also fix a small bug in the previous periodic_compaction_seconds default code.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6073
Test Plan: Add unit tests for it.
Differential Revision: D18669626
fbshipit-source-id: 957cd4374cafc1557d45a0ba002010552a378cc8
Summary:
`options.ttl` is now supported in universal compaction, similar to how periodic compactions are implemented in PR https://github.com/facebook/rocksdb/issues/5970 .
Setting `options.ttl` will simply set `options.periodic_compaction_seconds` to execute the periodic compactions code path.
Discarded PR https://github.com/facebook/rocksdb/issues/4749 in lieu of this.
This is a short term work-around/hack of falling back to periodic compactions when ttl is set.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6071
Test Plan: Added a unit test.
Differential Revision: D18668336
Pulled By: sagar0
fbshipit-source-id: e75f5b81ba949f77ef9eff05e44bb1c757f58612
Summary:
Previously, options.ttl cannot be set with options.max_open_files = -1, because it makes use of creation_time field in table properties, which is not available unless max_open_files = -1. With this commit, the information will be stored in manifest and when it is available, will be used instead.
Note that, this change will break forward compatibility for release 5.1 and older.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6060
Test Plan: Extend existing test case to options.max_open_files != -1, and simulate backward compatility in one test case by forcing the value to be 0.
Differential Revision: D18631623
fbshipit-source-id: 30c232a8672de5432ce9608bb2488ecc19138830
Summary:
## Problem Description
Our process was abort when it call `CheckConsistency`. And the information in `stderr` show that "`L0 files seqno 3001491972 3004797440 vs. 3002875611 3004524421` ". Here are the causes of the accident I investigated.
* RocksDB will call `CheckConsistency` whenever `MANIFEST` file is update. It will check sequence number interval of every file, except files which were ingested.
* When one file is ingested into RocksDB, it will be assigned the value of global sequence number, and the minimum and maximum seqno of this file are equal, which are both equal to global sequence number.
* `CheckConsistency` determines whether the file is ingested by whether the smallest and largest seqno of an sstable file are equal.
* If IntraL0Compaction picks one sst which was ingested just now and compacted it into another sst, the `smallest_seqno` of this new file will be smaller than his `largest_seqno`.
* If more than one ingested file was ingested before memtable schedule flush, and they all compact into one new sstable file by `IntraL0Compaction`. The sequence interval of this new file will be included in the interval of the memtable. So `CheckConsistency` will return a `Corruption`.
* If a sstable was ingested after the memtable was schedule to flush, which would assign a larger seqno to it than memtable. Then the file was compacted with other files (these files were all flushed before the memtable) in L0 into one file. This compaction start before the flush job of memtable start, but completed after the flush job finish. So this new file produced by the compaction (we call it s1) would have a larger interval of sequence number than the file produced by flush (we call it s2). **But there was still some data in s1 written into RocksDB before the s2, so it's possible that some data in s2 was cover by old data in s1.** Of course, it would also make a `Corruption` because of overlap of seqno. There is the relationship of the files:
> s1.smallest_seqno < s2.smallest_seqno < s2.largest_seqno < s1.largest_seqno
So I skip pick sst file which was ingested in function `FindIntraL0Compaction `
## Reason
Here is my bug report: https://github.com/facebook/rocksdb/issues/5913
There are two situations that can cause the check to fail.
### First situation：
- First we ingest five external sst into Rocksdb, and they happened to be ingested in L0. and there had been some data in memtable, which make the smallest sequence number of memtable is less than which of sst that we ingest.
- If there had been one compaction job which compacted sst from L0 to L1, `LevelCompactionPicker` would trigger a `IntraL0Compaction` which would compact this five sst from L0 to L0. We call this sst A, which was merged from five ingested sst.
- Then some data was put into memtable, and memtable was flushed to L0. We called this sst B.
- RocksDB check consistency , and find the `smallest_seqno` of B is less than that of A and crash. Because A was merged from five sst, the smallest sequence number of it was less than the biggest sequece number of itself, so RocksDB could not tell if A was produce by ingested.
### Secondary situaion
- First we have flushed many sst in L0, we call them [s1, s2, s3].
- There is an immutable memtable request to be flushed, but because flush thread is busy, so it has not been picked. we call it m1. And at the moment, one sst is ingested into L0. We call it s4. Because s4 is ingested after m1 became immutable memtable, so it has a larger log sequence number than m1.
- m1 is flushed in L0. because it is small, this flush job finish quickly. we call it s5.
- [s1, s2, s3, s4] are compacted into one sst to L0, by IntraL0Compaction. We call it s6.
- compacted 4@0 files to L0
- When s6 is added into manifest, the corruption happened. because the largest sequence number of s6 is equal to s4, and they are both larger than that of s5. But because s1 is older than m1, so the smallest sequence number of s6 is smaller than that of s5.
- s6.smallest_seqno < s5.smallest_seqno < s5.largest_seqno < s6.largest_seqno
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5958
Differential Revision: D18601316
fbshipit-source-id: 5fe54b3c9af52a2e1400728f565e895cde1c7267
Summary:
Recently, periodic compaction got turned on by default for leveled compaction is compaction filter is used. Since periodic compaction is now supported in universal compaction too, we do the same default for universal now.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5994
Test Plan: Add a new unit test.
Differential Revision: D18363744
fbshipit-source-id: 5093288ce990ee3cab0e44ffd92d8489fbcd6a48
Summary:
Right now, by default FIFO compaction has no TTL. We believe that a default TTL of 30 days will be better. With this patch, the default will be changed to 30 days. Default of Options.periodic_compaction_seconds will mean the same as options.ttl. If Options.ttl and Options.periodic_compaction_seconds left default, a default 30 days TTL will be used. If both options are set, the stricter value of the two will be used.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5987
Test Plan: Add an option sanitize test to cover the case.
Differential Revision: D18237935
fbshipit-source-id: a6dcea1f36c3849e13c0a69e413d73ad8eab58c9
Summary:
- Periodic compactions are auto-enabled if a compaction filter or a compaction filter factory is set, in Level Compaction.
- The default value of `periodic_compaction_seconds` is changed to UINT64_MAX, which lets RocksDB auto-tune periodic compactions as needed. An explicit value of 0 will still work as before ie. to disable periodic compactions completely. For now, on seeing a compaction filter along with a UINT64_MAX value for `periodic_compaction_seconds`, RocksDB will make SST files older than 30 days to go through periodic copmactions.
Some RocksDB users make use of compaction filters to control when their data can be deleted, usually with a custom TTL logic. But it is occasionally possible that the compactions get delayed by considerable time due to factors like low writes to a key range, data reaching bottom level, etc before the TTL expiry. Periodic Compactions feature was originally built to help such cases. Now periodic compactions are auto enabled by default when compaction filters or compaction filter factories are used, as it is generally helpful to all cases to collect garbage.
`periodic_compaction_seconds` is set to a large value, 30 days, in `SanitizeOptions` when RocksDB sees that a `compaction_filter` or `compaction_filter_factory` is used.
This is done only for Level Compaction style.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5865
Test Plan:
- Added a new test `DBCompactionTest.LevelPeriodicCompactionWithCompactionFilters` to make sure that `periodic_compaction_seconds` is set if either `compaction_filter` or `compaction_filter_factory` options are set.
- `COMPILE_WITH_ASAN=1 make check`
Differential Revision: D17659180
Pulled By: sagar0
fbshipit-source-id: 4887b9cf2e53cf2dc93a7b658c6b15e1181217ee
Summary:
Further apply formatter to more recent commits.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5830
Test Plan: Run all existing tests.
Differential Revision: D17488031
fbshipit-source-id: 137458fd94d56dd271b8b40c522b03036943a2ab
