Commit Graph

129 Commits

Author SHA1 Message Date
sdong
49628c9a83 Use std::numeric_limits<> (#9954)
Summary:
Right now we still don't fully use std::numeric_limits but use a macro, mainly for supporting VS 2013. Right now we only support VS 2017 and up so it is not a problem. The code comment claims that MinGW still needs it. We don't have a CI running MinGW so it's hard to validate. since we now require C++17, it's hard to imagine MinGW would still build RocksDB but doesn't support std::numeric_limits<>.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9954

Test Plan: See CI Runs.

Reviewed By: riversand963

Differential Revision: D36173954

fbshipit-source-id: a35a73af17cdcae20e258cdef57fcf29a50b49e0
2022-05-05 13:08:21 -07:00
Andrew Kryczka
c5d367f472 Revert open logic changes in #9634 (#9906)
Summary:
Left HISTORY.md and unit tests.
Added a new unit test to repro the corruption scenario that this PR fixes, and HISTORY.md line for that.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9906

Reviewed By: riversand963

Differential Revision: D35940093

Pulled By: ajkr

fbshipit-source-id: 9816f99e1ce405ba36f316beb4f6378c37c8c86b
2022-04-26 14:46:53 -07:00
Akanksha Mahajan
ae82d91492 Remove corrupted WAL files in kPointRecoveryMode with avoid_flush_duing_recovery set true (#9634)
Summary:
1) In case of non-TransactionDB and avoid_flush_during_recovery = true, RocksDB won't
flush the data from WAL to L0 for all column families if possible. As a
result, not all column families can increase their log_numbers, and
min_log_number_to_keep won't change.
2) For transaction DB (.allow_2pc), even with the flush, there may be old WAL files that it must not delete because they can contain data of uncommitted transactions and min_log_number_to_keep won't change.

If we persist a new MANIFEST with
advanced log_numbers for some column families, then during a second
crash after persisting the MANIFEST, RocksDB will see some column
families' log_numbers larger than the corrupted wal, and the "column family inconsistency" error will be hit, causing recovery to fail.

As a solution,
1. the corrupted WALs whose numbers are larger than the
corrupted wal and smaller than the new WAL will be moved to archive folder.
2. Currently, RocksDB DB::Open() may creates and writes to two new MANIFEST files even before recovery succeeds. This PR buffers the edits in a structure and writes to a new MANIFEST after recovery is successful

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9634

Test Plan:
1. Added new unit tests
                2. make crast_test -j

Reviewed By: riversand963

Differential Revision: D34463666

Pulled By: akankshamahajan15

fbshipit-source-id: e233d3af0ed4e2028ca0cf051e5a334a0fdc9d19
2022-04-11 15:39:31 -07:00
Yanqin Jin
0ad9ee30ce Remove dead code (#9825)
Summary:
Options `preserve_deletes` and `iter_start_seqnum` have been removed since 7.0.

This PR removes dead code related to these two removed options.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9825

Test Plan: make check

Reviewed By: akankshamahajan15

Differential Revision: D35517950

Pulled By: riversand963

fbshipit-source-id: 86282ce5ec4087acb94a06a42a1b6d55b1715482
2022-04-11 10:26:55 -07:00
Yanqin Jin
1a1c5bda23 Disallow commit-time-batch for write-prepared/write-unprepared txn conditionally (#9794)
Summary:
For write-prepared/write-unprepared transactions,
GetCommitTimeWriteBatch() can be used only if the transaction is started
with `TransactionOptions::use_only_the_last_commit_time_batch_for_recovery` set
to true. Otherwise, it is possible that multiple uncommitted versions of the
same key exist in the database. During bottommost compaction, RocksDB may
set the sequence numbers of both to zero once they become committed, causing
output SST file to have two identical internal keys.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9794

Test Plan:
make check
pay special attention to the following
```
transaction_test --gtest_filter=MySQLStyleTransactionTest/MySQLStyleTransactionTest.TransactionStressTest/*
```

Reviewed By: lth

Differential Revision: D35327214

Pulled By: riversand963

fbshipit-source-id: 3bae00a28359c10e96e4c6f676d20de5610d8a0f
2022-04-05 11:10:20 -07:00
Jay Zhuang
2c8100e60e Fix a race condition when disable and enable manual compaction (#9694)
Summary:
In https://github.com/facebook/rocksdb/issues/9659, when `DisableManualCompaction()` is issued, the foreground
manual compaction thread does not have to wait background compaction
thread to finish. Which could be a problem that the user re-enable
manual compaction with `EnableManualCompaction()`, it may re-enable the
BG compaction which supposed be cancelled.
This patch makes the FG compaction wait on
`manual_compaction_state.done`, which either be set by BG compaction or
Unschedule callback. Then when FG manual compaction thread returns, it
should not have BG compaction running. So shared_ptr is no longer needed
for `manual_compaction_state`.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9694

Test Plan: a StressTest and unittest

Reviewed By: ajkr

Differential Revision: D34885472

Pulled By: jay-zhuang

fbshipit-source-id: e6476175b43e8c59cd49f5c09241036a0716c274
2022-03-15 12:31:14 -07:00
Yanqin Jin
bbdaf63d0f Fix a TSAN-reported bug caused by concurrent accesss to std::deque (#9686)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9686

According to https://www.cplusplus.com/reference/deque/deque/back/,
"
The container is accessed (neither the const nor the non-const versions modify the container).
The last element is potentially accessed or modified by the caller. Concurrently accessing or modifying other elements is safe.
"

Also according to https://www.cplusplus.com/reference/deque/deque/pop_front/,
"
The container is modified.
The first element is modified. Concurrently accessing or modifying other elements is safe (although see iterator validity above).
"
In RocksDB, we never pop the last element of `DBImpl::alive_log_files_`. We have been
exploiting this fact and the above two properties when ensuring correctness when
`DBImpl::alive_log_files_` may be accessed concurrently. Specifically, it can be accessed
in the write path when db mutex is released. Sometimes, the log_mute_ is held. It can also be accessed in `FindObsoleteFiles()`
when db mutex is always held. It can also be accessed
during recovery when db mutex is also held.
Given the fact that we never pop the last element of alive_log_files_, we currently do not
acquire additional locks when accessing it in `WriteToWAL()` as follows
```
alive_log_files_.back().AddSize(log_entry.size());
```

This is problematic.

Check source code of deque.h
```
  back() _GLIBCXX_NOEXCEPT
  {
__glibcxx_requires_nonempty();
...
  }

  pop_front() _GLIBCXX_NOEXCEPT
  {
...
  if (this->_M_impl._M_start._M_cur
      != this->_M_impl._M_start._M_last - 1)
    {
      ...
      ++this->_M_impl._M_start._M_cur;
    }
  ...
  }
```

`back()` will actually call `__glibcxx_requires_nonempty()` first.
If `__glibcxx_requires_nonempty()` is enabled and not an empty macro,
it will call `empty()`
```
bool empty() {
return this->_M_impl._M_finish == this->_M_impl._M_start;
}
```
You can see that it will access `this->_M_impl._M_start`, racing with `pop_front()`.
Therefore, TSAN will actually catch the bug in this case.

To be able to use TSAN on our library and unit tests, we should always coordinate
concurrent accesses to STL containers properly.

We need to pass information about db mutex and log mutex into `WriteToWAL()`, otherwise
it's impossible to know which mutex to acquire inside the function.

To fix this, we can catch the tail of `alive_log_files_` by reference, so that we do not have to call `back()` in `WriteToWAL()`.

Reviewed By: pdillinger

Differential Revision: D34780309

fbshipit-source-id: 1def9821f0c437f2736c6a26445d75890377889b
2022-03-14 18:49:55 -07:00
Jay Zhuang
4dff279b19 DisableManualCompaction may fail to cancel an unscheduled task (#9659)
Summary:
https://github.com/facebook/rocksdb/issues/9625 didn't change the unschedule condition which was waiting for the background thread to clean-up the compaction.
make sure we only unschedule the task when it's scheduled.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9659

Reviewed By: ajkr

Differential Revision: D34651820

Pulled By: jay-zhuang

fbshipit-source-id: 23f42081b15ec8886cd81cbf131b116e0c74dc2f
2022-03-12 20:07:04 -08:00
Jay Zhuang
09b0e8f2c7 Fix a timer crash caused by invalid memory management (#9656)
Summary:
Timer crash when multiple DB instances doing heavy DB open and close
operations concurrently. Which is caused by adding a timer task with
smaller timestamp than the current running task. Fix it by moving the
getting new task timestamp part within timer mutex protection.
And other fixes:
- Disallow adding duplicated function name to timer
- Fix a minor memory leak in timer when a running task is cancelled

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9656

Reviewed By: ajkr

Differential Revision: D34626296

Pulled By: jay-zhuang

fbshipit-source-id: 6b6d96a5149746bf503546244912a9e41a0c5f6b
2022-03-12 11:45:56 -08:00
slk
95305c44a1 Add OpenAndTrimHistory API to support trimming data with specified timestamp (#9410)
Summary:
As disscussed in (https://github.com/facebook/rocksdb/issues/9223), Here added a new API  named DB::OpenAndTrimHistory, this API will open DB and trim data to the timestamp specofied by **trim_ts** (The data with newer timestamp than specified trim bound will be removed). This API should only be used at a timestamp-enabled db instance recovery.

And this PR implemented a new iterator named HistoryTrimmingIterator to support trimming history with a new API named DB::OpenAndTrimHistory. HistoryTrimmingIterator wrapped around the underlying InternalITerator such that keys whose timestamps newer than **trim_ts** should not be returned to the compaction iterator while **trim_ts** is not null.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9410

Reviewed By: ltamasi

Differential Revision: D34410207

Pulled By: riversand963

fbshipit-source-id: e54049dc234eccd673244c566b15df58df5a6236
2022-03-11 16:13:23 -08:00
Hui Xiao
ca0ef54f16 Rate-limit automatic WAL flush after each user write (#9607)
Summary:
**Context:**
WAL flush is currently not rate-limited by `Options::rate_limiter`. This PR is to provide rate-limiting to auto WAL flush, the one that automatically happen after each user write operation (i.e, `Options::manual_wal_flush == false`), by adding `WriteOptions::rate_limiter_options`.

Note that we are NOT rate-limiting WAL flush that do NOT automatically happen after each user write, such as  `Options::manual_wal_flush == true + manual FlushWAL()` (rate-limiting multiple WAL flushes),  for the benefits of:
- being consistent with [ReadOptions::rate_limiter_priority](https://github.com/facebook/rocksdb/blob/7.0.fb/include/rocksdb/options.h#L515)
- being able to turn off some WAL flush's rate-limiting but not all (e.g, turn off specific the WAL flush of a critical user write like a service's heartbeat)

`WriteOptions::rate_limiter_options` only accept `Env::IO_USER` and `Env::IO_TOTAL` currently due to an implementation constraint.
- The constraint is that we currently queue parallel writes (including WAL writes) based on FIFO policy which does not factor rate limiter priority into this layer's scheduling. If we allow lower priorities such as `Env::IO_HIGH/MID/LOW` and such writes specified with lower priorities occurs before ones specified with higher priorities (even just by a tiny bit in arrival time), the former would have blocked the latter, leading to a "priority inversion" issue and contradictory to what we promise for rate-limiting priority. Therefore we only allow `Env::IO_USER` and `Env::IO_TOTAL`  right now before improving that scheduling.

A pre-requisite to this feature is to support operation-level rate limiting in `WritableFileWriter`, which is also included in this PR.

**Summary:**
- Renamed test suite `DBRateLimiterTest to DBRateLimiterOnReadTest` for adding a new test suite
- Accept `rate_limiter_priority` in `WritableFileWriter`'s private and public write functions
- Passed `WriteOptions::rate_limiter_options` to `WritableFileWriter` in the path of automatic WAL flush.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9607

Test Plan:
- Added new unit test to verify existing flush/compaction rate-limiting does not break, since `DBTest, RateLimitingTest` is disabled and current db-level rate-limiting tests focus on read only (e.g, `db_rate_limiter_test`, `DBTest2, RateLimitedCompactionReads`).
- Added new unit test `DBRateLimiterOnWriteWALTest, AutoWalFlush`
- `strace -ftt -e trace=write ./db_bench -benchmarks=fillseq -db=/dev/shm/testdb -rate_limit_auto_wal_flush=1 -rate_limiter_bytes_per_sec=15 -rate_limiter_refill_period_us=1000000 -write_buffer_size=100000000 -disable_auto_compactions=1 -num=100`
   - verified that WAL flush(i.e, system-call _write_) were chunked into 15 bytes and each _write_ was roughly 1 second apart
   - verified the chunking disappeared when `-rate_limit_auto_wal_flush=0`
- crash test: `python3 tools/db_crashtest.py blackbox --disable_wal=0  --rate_limit_auto_wal_flush=1 --rate_limiter_bytes_per_sec=10485760 --interval=10` killed as normal

**Benchmarked on flush/compaction to ensure no performance regression:**
- compaction with rate-limiting  (see table 1, avg over 1280-run):  pre-change: **915635 micros/op**; post-change:
   **907350 micros/op (improved by 0.106%)**
```
#!/bin/bash
TEST_TMPDIR=/dev/shm/testdb
START=1
NUM_DATA_ENTRY=8
N=10

rm -f compact_bmk_output.txt compact_bmk_output_2.txt dont_care_output.txt
for i in $(eval echo "{$START..$NUM_DATA_ENTRY}")
do
    NUM_RUN=$(($N*(2**($i-1))))
    for j in $(eval echo "{$START..$NUM_RUN}")
    do
       ./db_bench --benchmarks=fillrandom -db=$TEST_TMPDIR -disable_auto_compactions=1 -write_buffer_size=6710886 > dont_care_output.txt && ./db_bench --benchmarks=compact -use_existing_db=1 -db=$TEST_TMPDIR -level0_file_num_compaction_trigger=1 -rate_limiter_bytes_per_sec=100000000 | egrep 'compact'
    done > compact_bmk_output.txt && awk -v NUM_RUN=$NUM_RUN '{sum+=$3;sum_sqrt+=$3^2}END{print sum/NUM_RUN, sqrt(sum_sqrt/NUM_RUN-(sum/NUM_RUN)^2)}' compact_bmk_output.txt >> compact_bmk_output_2.txt
done
```
- compaction w/o rate-limiting  (see table 2, avg over 640-run):  pre-change: **822197 micros/op**; post-change: **823148 micros/op (regressed by 0.12%)**
```
Same as above script, except that -rate_limiter_bytes_per_sec=0
```
- flush with rate-limiting (see table 3, avg over 320-run, run on the [patch](ee5c6023a9) to augment current db_bench ): pre-change: **745752 micros/op**; post-change: **745331 micros/op (regressed by 0.06 %)**
```
 #!/bin/bash
TEST_TMPDIR=/dev/shm/testdb
START=1
NUM_DATA_ENTRY=8
N=10

rm -f flush_bmk_output.txt flush_bmk_output_2.txt

for i in $(eval echo "{$START..$NUM_DATA_ENTRY}")
do
    NUM_RUN=$(($N*(2**($i-1))))
    for j in $(eval echo "{$START..$NUM_RUN}")
    do
       ./db_bench -db=$TEST_TMPDIR -write_buffer_size=1048576000 -num=1000000 -rate_limiter_bytes_per_sec=100000000 -benchmarks=fillseq,flush | egrep 'flush'
    done > flush_bmk_output.txt && awk -v NUM_RUN=$NUM_RUN '{sum+=$3;sum_sqrt+=$3^2}END{print sum/NUM_RUN, sqrt(sum_sqrt/NUM_RUN-(sum/NUM_RUN)^2)}' flush_bmk_output.txt >> flush_bmk_output_2.txt
done

```
- flush w/o rate-limiting (see table 4, avg over 320-run, run on the [patch](ee5c6023a9) to augment current db_bench): pre-change: **487512 micros/op**, post-change: **485856 micors/ops (improved by 0.34%)**
```
Same as above script, except that -rate_limiter_bytes_per_sec=0
```

| table 1 - compact with rate-limiting|
#-run | (pre-change) avg micros/op | std micros/op | (post-change)  avg micros/op | std micros/op | change in avg micros/op  (%)
-- | -- | -- | -- | -- | --
10 | 896978 | 16046.9 | 901242 | 15670.9 | 0.475373978
20 | 893718 | 15813 | 886505 | 17544.7 | -0.8070778478
40 | 900426 | 23882.2 | 894958 | 15104.5 | -0.6072681153
80 | 906635 | 21761.5 | 903332 | 23948.3 | -0.3643141948
160 | 898632 | 21098.9 | 907583 | 21145 | 0.9960695813
3.20E+02 | 905252 | 22785.5 | 908106 | 25325.5 | 0.3152713278
6.40E+02 | 905213 | 23598.6 | 906741 | 21370.5 | 0.1688000504
**1.28E+03** | **908316** | **23533.1** | **907350** | **24626.8** | **-0.1063506533**
average over #-run | 901896.25 | 21064.9625 | 901977.125 | 20592.025 | 0.008967217682

| table 2 - compact w/o rate-limiting|
#-run | (pre-change) avg micros/op | std micros/op | (post-change)  avg micros/op | std micros/op | change in avg micros/op  (%)
-- | -- | -- | -- | -- | --
10 | 811211 | 26996.7 | 807586 | 28456.4 | -0.4468627768
20 | 815465 | 14803.7 | 814608 | 28719.7 | -0.105093413
40 | 809203 | 26187.1 | 797835 | 25492.1 | -1.404839082
80 | 822088 | 28765.3 | 822192 | 32840.4 | 0.01265071379
160 | 821719 | 36344.7 | 821664 | 29544.9 | -0.006693285661
3.20E+02 | 820921 | 27756.4 | 821403 | 28347.7 | 0.05871454135
**6.40E+02** | **822197** | **28960.6** | **823148** | **30055.1** | **0.1156657103**
average over #-run | 8.18E+05 | 2.71E+04 | 8.15E+05 | 2.91E+04 |  -0.25

| table 3 - flush with rate-limiting|
#-run | (pre-change) avg micros/op | std micros/op | (post-change)  avg micros/op | std micros/op | change in avg micros/op  (%)
-- | -- | -- | -- | -- | --
10 | 741721 | 11770.8 | 740345 | 5949.76 | -0.1855144994
20 | 735169 | 3561.83 | 743199 | 9755.77 | 1.09226586
40 | 743368 | 8891.03 | 742102 | 8683.22 | -0.1703059588
80 | 742129 | 8148.51 | 743417 | 9631.58| 0.1735547324
160 | 749045 | 9757.21 | 746256 | 9191.86 | -0.3723407806
**3.20E+02** | **745752** | **9819.65** | **745331** | **9840.62** | **-0.0564530836**
6.40E+02 | 749006 | 11080.5 | 748173 | 10578.7 | -0.1112140624
average over #-run | 743741.4286 | 9004.218571 | 744117.5714 | 9090.215714 | 0.05057441238

| table 4 - flush w/o rate-limiting|
#-run | (pre-change) avg micros/op | std micros/op | (post-change)  avg micros/op | std micros/op | change in avg micros/op (%)
-- | -- | -- | -- | -- | --
10 | 477283 | 24719.6 | 473864 | 12379 | -0.7163464863
20 | 486743 | 20175.2 | 502296 | 23931.3 | 3.195320734
40 | 482846 | 15309.2 | 489820 | 22259.5 | 1.444352858
80 | 491490 | 21883.1 | 490071 | 23085.7 | -0.2887139108
160 | 493347 | 28074.3 | 483609 | 21211.7 | -1.973864238
**3.20E+02** | **487512** | **21401.5** | **485856** | **22195.2** | **-0.3396839462**
6.40E+02 | 490307 | 25418.6 | 485435 | 22405.2 | -0.9936631539
average over #-run | 4.87E+05 | 2.24E+04 | 4.87E+05 | 2.11E+04 | 0.00E+00

Reviewed By: ajkr

Differential Revision: D34442441

Pulled By: hx235

fbshipit-source-id: 4790f13e1e5c0a95ae1d1cc93ffcf69dc6e78bdd
2022-03-08 13:19:39 -08:00
Jay Zhuang
db8647969d Unschedule manual compaction from thread-pool queue (#9625)
Summary:
PR https://github.com/facebook/rocksdb/issues/9557 introduced a race condition between manual compaction
foreground thread and background compaction thread.
This PR adds the ability to really unschedule manual compaction from
thread-pool queue by differentiate tag name for manual compaction and
other tasks.
Also fix an issue that db `close()` didn't cancel the manual compaction thread.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9625

Test Plan: unittest not hang

Reviewed By: ajkr

Differential Revision: D34410811

Pulled By: jay-zhuang

fbshipit-source-id: cb14065eabb8cf1345fa042b5652d4f788c0c40c
2022-03-02 13:43:00 -08:00
Andrew Kryczka
9983eecdfb Dedicate cacheline for DB mutex (#9637)
Summary:
We found a case of cacheline bouncing due to writers locking/unlocking `mutex_` and readers accessing `block_cache_tracer_`. We discovered it only after the issue was fixed by https://github.com/facebook/rocksdb/issues/9462 shifting the `DBImpl` members such that `mutex_` and `block_cache_tracer_` were naturally placed in separate cachelines in our regression testing setup. This PR forces the cacheline alignment of `mutex_` so we don't accidentally reintroduce the problem.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9637

Reviewed By: riversand963

Differential Revision: D34502233

Pulled By: ajkr

fbshipit-source-id: 46aa313b7fe83e80c3de254e332b6fb242434c07
2022-02-27 11:36:54 -08:00
Yanqin Jin
1cda273dc3 Fix a silent data loss for write-committed txn (#9571)
Summary:
The following sequence of events can cause silent data loss for write-committed
transactions.
```
Time    thread 1                                       bg flush
 |   db->Put("a")
 |   txn = NewTxn()
 |   txn->Put("b", "v")
 |   txn->Prepare()       // writes only to 5.log
 |   db->SwitchMemtable() // memtable 1 has "a"
 |                        // close 5.log,
 |                        // creates 8.log
 |   trigger flush
 |                                                  pick memtable 1
 |                                                  unlock db mutex
 |                                                  write new sst
 |   txn->ctwb->Put("gtid", "1") // writes 8.log
 |   txn->Commit() // writes to 8.log
 |                 // writes to memtable 2
 |                                               compute min_log_number_to_keep_2pc, this
 |                                               will be 8 (incorrect).
 |
 |                                             Purge obsolete wals, including 5.log
 |
 V
```

At this point, writes of txn exists only in memtable. Close db without flush because db thinks the data in
memtable are backed by log. Then reopen, the writes are lost except key-value pair {"gtid"->"1"},
only the commit marker of txn is in 8.log

The reason lies in `PrecomputeMinLogNumberToKeep2PC()` which calls `FindMinPrepLogReferencedByMemTable()`.
In the above example, when bg flush thread tries to find obsolete wals, it uses the information
computed by `PrecomputeMinLogNumberToKeep2PC()`. The return value of `PrecomputeMinLogNumberToKeep2PC()`
depends on three components
- `PrecomputeMinLogNumberToKeepNon2PC()`. This represents the WAL that has unflushed data. As the name of this method suggests, it does not account for 2PC. Although the keys reside in the prepare section of a previous WAL, the column family references the current WAL when they are actually inserted into the memtable during txn commit.
- `prep_tracker->FindMinLogContainingOutstandingPrep()`. This represents the WAL with a prepare section but the txn hasn't committed.
- `FindMinPrepLogReferencedByMemTable()`. This represents the WAL on which some memtables (mutable and immutable) depend for their unflushed data.

The bug lies in `FindMinPrepLogReferencedByMemTable()`. Originally, this function skips checking the column families
that are being flushed, but the unit test added in this PR shows that they should not be. In this unit test, there is
only the default column family, and one of its memtables has unflushed data backed by a prepare section in 5.log.
We should return this information via `FindMinPrepLogReferencedByMemTable()`.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9571

Test Plan:
```
./transaction_test --gtest_filter=*/TransactionTest.SwitchMemtableDuringPrepareAndCommit_WC/*
make check
```

Reviewed By: siying

Differential Revision: D34235236

Pulled By: riversand963

fbshipit-source-id: 120eb21a666728a38dda77b96276c6af72b008b1
2022-02-16 23:08:58 -08:00
Jay Zhuang
a0c569ee1d Cancel manual compaction in thread-pool queue (#9557)
Summary:
Fix `DisableManualCompaction()` has to wait scheduled manual compaction to start the execution to cancel the job.
When a manual compaction in thread-pool queue is cancel, set the job is_canceled to true and clean the resource.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9557

Test Plan: added unittest that will hang without the change

Reviewed By: ajkr

Differential Revision: D34214910

Pulled By: jay-zhuang

fbshipit-source-id: 89dbaee78ddf26eb13ce862c2b15f4a098b36a78
2022-02-15 19:23:01 -08:00
Yanqin Jin
3122cb4358 Revise APIs related to user-defined timestamp (#8946)
Summary:
ajkr reminded me that we have a rule of not including per-kv related data in `WriteOptions`.
Namely, `WriteOptions` should not include information about "what-to-write", but should just
include information about "how-to-write".

According to this rule, `WriteOptions::timestamp` (experimental) is clearly a violation. Therefore,
this PR removes `WriteOptions::timestamp` for compliance.
After the removal, we need to pass timestamp info via another set of APIs. This PR proposes a set
of overloaded functions `Put(write_opts, key, value, ts)`, `Delete(write_opts, key, ts)`, and
`SingleDelete(write_opts, key, ts)`. Planned to add `Write(write_opts, batch, ts)`, but its complexity
made me reconsider doing it in another PR (maybe).

For better checking and returning error early, we also add a new set of APIs to `WriteBatch` that take
extra `timestamp` information when writing to `WriteBatch`es.
These set of APIs in `WriteBatchWithIndex` are currently not supported, and are on our TODO list.

Removed `WriteBatch::AssignTimestamps()` and renamed `WriteBatch::AssignTimestamp()` to
`WriteBatch::UpdateTimestamps()` since this method require that all keys have space for timestamps
allocated already and multiple timestamps can be updated.

The constructor of `WriteBatch` now takes a fourth argument `default_cf_ts_sz` which is the timestamp
size of the default column family. This will be used to allocate space when calling APIs that do not
specify a column family handle.

Also, updated `DB::Get()`, `DB::MultiGet()`, `DB::NewIterator()`, `DB::NewIterators()` methods, replacing
some assertions about timestamp to returning Status code.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8946

Test Plan:
make check
./db_bench -benchmarks=fillseq,fillrandom,readrandom,readseq,deleterandom -user_timestamp_size=8
./db_stress --user_timestamp_size=8 -nooverwritepercent=0 -test_secondary=0 -secondary_catch_up_one_in=0 -continuous_verification_interval=0

Make sure there is no perf regression by running the following
```
./db_bench_opt -db=/dev/shm/rocksdb -use_existing_db=0 -level0_stop_writes_trigger=256 -level0_slowdown_writes_trigger=256 -level0_file_num_compaction_trigger=256 -disable_wal=1 -duration=10 -benchmarks=fillrandom
```

Before this PR
```
DB path: [/dev/shm/rocksdb]
fillrandom   :       1.831 micros/op 546235 ops/sec;   60.4 MB/s
```
After this PR
```
DB path: [/dev/shm/rocksdb]
fillrandom   :       1.820 micros/op 549404 ops/sec;   60.8 MB/s
```

Reviewed By: ltamasi

Differential Revision: D33721359

Pulled By: riversand963

fbshipit-source-id: c131561534272c120ffb80711d42748d21badf09
2022-02-01 22:19:01 -08:00
Jay Zhuang
980b9ff385 Add more micro-benchmark tests (#9436)
Summary:
* Add more micro-benchmark tests
* Expose an API in DBImpl for waiting for compactions (still not visible to the user)
* Add argument name for ribbon_bench
* remove benchmark run from CI, as it runs too long.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9436

Test Plan: CI

Reviewed By: riversand963

Differential Revision: D33777836

Pulled By: jay-zhuang

fbshipit-source-id: c05de3bc082cc05b5d019f00b324e774bf4bbd96
2022-02-01 09:01:55 -08:00
Yanqin Jin
d10c5c08d3 Remove iter_start_seqnum and preserve_deletes (#9430)
Summary:
According to https://github.com/facebook/rocksdb/blob/6.27.fb/db/db_impl/db_impl.cc#L2896:L2911 and https://github.com/facebook/rocksdb/blob/6.27.fb/db/db_impl/db_impl_open.cc#L203:L208,
we are going to remove `iter_start_seqnum` and `preserve_deletes` starting from RocksDB 7.0

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9430

Test Plan: make check and CI

Reviewed By: ajkr

Differential Revision: D33753639

Pulled By: riversand963

fbshipit-source-id: c80aab8e8d8fc33e52472fed524ed703d0ffc8b6
2022-01-28 13:28:38 -08:00
slk
2e5f764294 Make IncreaseFullHistoryTsLow to a public API (#9221)
Summary:
As (https://github.com/facebook/rocksdb/issues/9210) discussed, the **full_history_ts_low** is a member of CompactRangeOptions currently, which means a CF's fullHistoryTsLow is advanced only when users submit a CompactRange request.
However, users may want to advance the fllHistoryTsLow without an immediate compact.
This merge make IncreaseFullHistoryTsLow to a public API so users can advance each CF's fullHistoryTsLow seperately.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9221

Reviewed By: akankshamahajan15

Differential Revision: D33201106

Pulled By: riversand963

fbshipit-source-id: 9cb1d013ba93260f72e16353e693ffee167b47ee
2021-12-23 11:03:51 -08:00
Andrew Kryczka
538d2365e9 Fix race condition in BackupEngineTest.ChangeManifestDuringBackupCreation (#9327)
Summary:
The failure looked like this:

```
utilities/backupable/backupable_db_test.cc:3161: Failure
Value of: db_chroot_env_->FileExists(prev_manifest_path).IsNotFound()
  Actual: false
Expected: true
```

The failure could be coerced consistently with the following patch:

```
 diff --git a/db/db_impl/db_impl_compaction_flush.cc b/db/db_impl/db_impl_compaction_flush.cc
index 80410f671..637636791 100644
 --- a/db/db_impl/db_impl_compaction_flush.cc
+++ b/db/db_impl/db_impl_compaction_flush.cc
@@ -2772,6 +2772,8 @@ void DBImpl::BackgroundCallFlush(Env::Priority thread_pri) {
     if (job_context.HaveSomethingToClean() ||
         job_context.HaveSomethingToDelete() || !log_buffer.IsEmpty()) {
       mutex_.Unlock();
+      bg_cv_.SignalAll();
+      sleep(1);
       TEST_SYNC_POINT("DBImpl::BackgroundCallFlush:FilesFound");
       // Have to flush the info logs before bg_flush_scheduled_--
       // because if bg_flush_scheduled_ becomes 0 and the lock is
```

The cause was a familiar problem, which is manual flush/compaction may
return before files they obsoleted are removed. The solution is just to
wait for "scheduled" work to complete, which includes all phases
including cleanup.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9327

Test Plan:
after this PR, even the above patch to coerce the bug cannot
cause the test to fail.

Reviewed By: riversand963

Differential Revision: D33252208

Pulled By: ajkr

fbshipit-source-id: 720a7eaca58c7247d221911fffe3d5e1dbf581e9
2021-12-22 21:59:53 -08:00
Peter Dillinger
0050a73a4f New stable, fixed-length cache keys (#9126)
Summary:
This change standardizes on a new 16-byte cache key format for
block cache (incl compressed and secondary) and persistent cache (but
not table cache and row cache).

The goal is a really fast cache key with practically ideal stability and
uniqueness properties without external dependencies (e.g. from FileSystem).
A fixed key size of 16 bytes should enable future optimizations to the
concurrent hash table for block cache, which is a heavy CPU user /
bottleneck, but there appears to be measurable performance improvement
even with no changes to LRUCache.

This change replaces a lot of disjointed and ugly code handling cache
keys with calls to a simple, clean new internal API (cache_key.h).
(Preserving the old cache key logic under an option would be very ugly
and likely negate the performance gain of the new approach. Complete
replacement carries some inherent risk, but I think that's acceptable
with sufficient analysis and testing.)

The scheme for encoding new cache keys is complicated but explained
in cache_key.cc.

Also: EndianSwapValue is moved to math.h to be next to other bit
operations. (Explains some new include "math.h".) ReverseBits operation
added and unit tests added to hash_test for both.

Fixes https://github.com/facebook/rocksdb/issues/7405 (presuming a root cause)

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9126

Test Plan:
### Basic correctness
Several tests needed updates to work with the new functionality, mostly
because we are no longer relying on filesystem for stable cache keys
so table builders & readers need more context info to agree on cache
keys. This functionality is so core, a huge number of existing tests
exercise the cache key functionality.

### Performance
Create db with
`TEST_TMPDIR=/dev/shm ./db_bench -bloom_bits=10 -benchmarks=fillrandom -num=3000000 -partition_index_and_filters`
And test performance with
`TEST_TMPDIR=/dev/shm ./db_bench -readonly -use_existing_db -bloom_bits=10 -benchmarks=readrandom -num=3000000 -duration=30 -cache_index_and_filter_blocks -cache_size=250000 -threads=4`
using DEBUG_LEVEL=0 and simultaneous before & after runs.
Before ops/sec, avg over 100 runs: 121924
After ops/sec, avg over 100 runs: 125385 (+2.8%)

### Collision probability
I have built a tool, ./cache_bench -stress_cache_key to broadly simulate host-wide cache activity
over many months, by making some pessimistic simplifying assumptions:
* Every generated file has a cache entry for every byte offset in the file (contiguous range of cache keys)
* All of every file is cached for its entire lifetime

We use a simple table with skewed address assignment and replacement on address collision
to simulate files coming & going, with quite a variance (super-Poisson) in ages. Some output
with `./cache_bench -stress_cache_key -sck_keep_bits=40`:

```
Total cache or DBs size: 32TiB  Writing 925.926 MiB/s or 76.2939TiB/day
Multiply by 9.22337e+18 to correct for simulation losses (but still assume whole file cached)
```

These come from default settings of 2.5M files per day of 32 MB each, and
`-sck_keep_bits=40` means that to represent a single file, we are only keeping 40 bits of
the 128-bit cache key.  With file size of 2\*\*25 contiguous keys (pessimistic), our simulation
is about 2\*\*(128-40-25) or about 9 billion billion times more prone to collision than reality.

More default assumptions, relatively pessimistic:
* 100 DBs in same process (doesn't matter much)
* Re-open DB in same process (new session ID related to old session ID) on average
every 100 files generated
* Restart process (all new session IDs unrelated to old) 24 times per day

After enough data, we get a result at the end:

```
(keep 40 bits)  17 collisions after 2 x 90 days, est 10.5882 days between (9.76592e+19 corrected)
```

If we believe the (pessimistic) simulation and the mathematical generalization, we would need to run a billion machines all for 97 billion days to expect a cache key collision. To help verify that our generalization ("corrected") is robust, we can make our simulation more precise with `-sck_keep_bits=41` and `42`, which takes more running time to get enough data:

```
(keep 41 bits)  16 collisions after 4 x 90 days, est 22.5 days between (1.03763e+20 corrected)
(keep 42 bits)  19 collisions after 10 x 90 days, est 47.3684 days between (1.09224e+20 corrected)
```

The generalized prediction still holds. With the `-sck_randomize` option, we can see that we are beating "random" cache keys (except offsets still non-randomized) by a modest amount (roughly 20x less collision prone than random), which should make us reasonably comfortable even in "degenerate" cases:

```
197 collisions after 1 x 90 days, est 0.456853 days between (4.21372e+18 corrected)
```

I've run other tests to validate other conditions behave as expected, never behaving "worse than random" unless we start chopping off structured data.

Reviewed By: zhichao-cao

Differential Revision: D33171746

Pulled By: pdillinger

fbshipit-source-id: f16a57e369ed37be5e7e33525ace848d0537c88f
2021-12-16 17:15:13 -08:00
Yanqin Jin
bd513fd075 Add commit marker with timestamp (#9266)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9266

This diff adds a new tag `CommitWithTimestamp`. Currently, there is no API to trigger writing
this tag to WAL, thus it is unavailable to users.
This is an ongoing effort to add user-defined timestamp support to write-committed transactions.
This diff also indicates all column families that may potentially participate in the same
transaction must either disable timestamp or have the same timestamp format, since
`CommitWithTimestamp` tag is followed by a single byte-array denoting the commit
timestamp of the transaction. We will enforce this checking in a future diff. We keep this
diff small.

Reviewed By: ltamasi

Differential Revision: D31721350

fbshipit-source-id: e1450811443647feb6ca01adec4c8aaae270ffc6
2021-12-10 11:05:35 -08:00
Jay Zhuang
6cde8d2190 Deprecating iter_start_seqnum and preserve_deletes (#9091)
Summary:
`ReadOptions::iter_start_seqnum` and `DBOptions::preserve_deletes` are
deprecated, please try using user defined timestamp feature instead.
The feature is used to support differential snapshots, but not well
maintained (https://github.com/facebook/rocksdb/issues/6837, https://github.com/facebook/rocksdb/issues/8472) and the interface is not user friendly which
returns an internal key from the iterator. The user defined timestamp
feature is a more flexible feature to support similar usecase, please
switch to that if you have such usecase.
The deprecated feature will be removed in a future release.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9091

Test Plan:
check LOG

Fix https://github.com/facebook/rocksdb/issues/9090

Reviewed By: ajkr

Differential Revision: D32071750

Pulled By: jay-zhuang

fbshipit-source-id: b882c4668dd1bf26ce03c4c192f1bba584bf6104
2021-11-19 16:55:45 -08:00
Yanqin Jin
2035798834 Update TransactionUtil::CheckKeyForConflict to also use timestamps (#9162)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9162

Existing TransactionUtil::CheckKeyForConflict() performs only seq-based
conflict checking. If user-defined timestamp is enabled, it should perform
conflict checking based on timestamps too.

Update TransactionUtil::CheckKey-related methods to verify the timestamp of the
latest version of a key is smaller than the read timestamp. Note that
CheckKeysForConflict() is not updated since it's used only by optimistic
transaction, and we do not plan to update it in this upcoming batch of diffs.

Existing GetLatestSequenceForKey() returns the sequence of the latest
version of a specific user key. Since we support user-defined timestamp, we
need to update this method to also return the timestamp (if enabled) of the
latest version of the key. This will be needed for snapshot validation.

Reviewed By: ltamasi

Differential Revision: D31567960

fbshipit-source-id: 2e4a14aed267435a9aa91bc632d2411c01946d44
2021-11-15 12:52:18 -08:00
Jay Zhuang
29102641dd Skip directory fsync for filesystem btrfs (#8903)
Summary:
Directory fsync might be expensive on btrfs and it may not be needed.
Here are 4 directory fsync cases:
1. creating a new file: dir-fsync is not needed on btrfs, as long as the
   new file itself is synced.
2. renaming a file: dir-fsync is not needed if the renamed file is
   synced. So an API `FsyncAfterFileRename(filename, ...)` is provided
   to sync the file on btrfs. By default, it just calls dir-fsync.
3. deleting files: dir-fsync is forced by set
   `IOOptions.force_dir_fsync = true`
4. renaming multiple files (like backup and checkpoint): dir-fsync is
   forced, the same as above.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8903

Test Plan: run tests on btrfs and non btrfs

Reviewed By: ajkr

Differential Revision: D30885059

Pulled By: jay-zhuang

fbshipit-source-id: dd2730b31580b0bcaedffc318a762d7dbf25de4a
2021-11-03 12:21:27 -07:00
Jay Zhuang
314de7e7de Make DB::Close() thread-safe (#8970)
Summary:
If `DB::Close()` is called in multi-thread env, the resource
could be double released, which causes exception or assert.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8970

Test Plan:
Test with multi-thread benchmark, with each thread try to
close the DB at the end.

Reviewed By: pdillinger

Differential Revision: D31242042

Pulled By: jay-zhuang

fbshipit-source-id: a61276b1b61e07732e375554106946aea86a23eb
2021-10-18 20:32:35 -07:00
Peter Dillinger
3ffb3baa0b Add (Live)FileStorageInfo API (#8968)
Summary:
New classes FileStorageInfo and LiveFileStorageInfo and
'experimental' function DB::GetLiveFilesStorageInfo, which is intended
to largely replace several fragmented DB functions needed to create
checkpoints and backups.

This function is now used to create checkpoints and backups, because
it fixes many (probably not all) of the prior complexities of checkpoint
not having atomic access to DB metadata. This also ensures strong
functional test coverage of the new API. Specifically, much of the old
CheckpointImpl::CreateCustomCheckpoint has been migrated to and
updated in DBImpl::GetLiveFilesStorageInfo, with the former now
calling the latter.

Also, the class FileStorageInfo in metadata.h compatibly replaces
BackupFileInfo and serves as a new base class for SstFileMetaData.
Some old fields of SstFileMetaData are still provided (for now) but
deprecated.

Although FileStorageInfo::directory is accurate when using db_paths
and/or cf_paths, these have never been supported by Checkpoint
nor BackupEngine and still are not. This change does now detect
these cases and return NotSupported when appropriate. (More work
needed for support.)

Somehow this change broke ProgressCallbackDuringBackup, but
the progress_callback logic was dubious to begin with because it
would call the callback based on copy buffer size, not size actually
copied. Logic and test updated to track size actually copied
per-thread.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8968

Test Plan:
tests updated.
DB::GetLiveFilesStorageInfo mostly tested by use in CheckpointImpl.
DBTest.SnapshotFiles updated to also test GetLiveFilesStorageInfo,
including reading the data after DB close.
Added CheckpointTest.CheckpointWithDbPath (NotSupported).

Reviewed By: siying

Differential Revision: D31242045

Pulled By: pdillinger

fbshipit-source-id: b183d1ce9799e220daaefd6b3b5365d98de676c0
2021-10-16 10:04:32 -07:00
Giuseppe Ottaviano
22d4dc5066 Fix race in WriteBufferManager (#9009)
Summary:
EndWriteStall has a data race: `queue_.empty()` is checked outside of the
mutex, so once we enter the critical section another thread may already have
cleared the list, and accessing the `front()` is undefined behavior (and causes
interesting crashes under high concurrency).

This PR fixes the bug, and also rewrites the logic to make it easier to reason
about it. It also fixes another subtle bug: if some writers are stalled and
`SetBufferSize(0)` is called, which disables the WBM, the writer are not
unblocked because of an early `enabled()` check in `EndWriteStall()`.

It doesn't significantly change the locking behavior, as before writers won't
lock unless entering a stall condition, and `FreeMem` almost always locks if
stalling is allowed, but that is inevitable with the current design. Liveness is
guaranteed by the fact that if some writes are blocked, eventually all writes
will be blocked due to `stall_active_`, and eventually all memory is freed.

While at it, do a couple of optimizations:

- In `WBMStallInterface::Signal()` signal the CV only after releasing the
  lock. Signaling under the lock is a common pitfall, as it causes the woken-up
  thread to immediately go back to sleep because the mutex is still locked by
  the awaker.

- Move all allocations and deallocations outside of the lock.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9009

Test Plan:
```
USE_CLANG=1 make -j64 all check
```

Reviewed By: akankshamahajan15

Differential Revision: D31550668

Pulled By: ot

fbshipit-source-id: 5125387c3dc7ecaaa2b8bbc736e58c4156698580
2021-10-12 00:16:21 -07:00
mrambacher
13ae16c315 Cleanup includes in dbformat.h (#8930)
Summary:
This header file was including everything and the kitchen sink when it did not need to.  This resulted in many places including this header when they needed other pieces instead.

Cleaned up this header to only include what was needed and fixed up the remaining code to include what was now missing.

Hopefully, this sort of code hygiene cleanup will speed up the builds...

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8930

Reviewed By: pdillinger

Differential Revision: D31142788

Pulled By: mrambacher

fbshipit-source-id: 6b45de3f300750c79f751f6227dece9cfd44085d
2021-09-29 04:04:40 -07:00
Peter Dillinger
4750421ece Replace most typedef with using= (#8751)
Summary:
Old typedef syntax is confusing

Most but not all changes with

    perl -pi -e 's/typedef (.*) ([a-zA-Z0-9_]+);/using $2 = $1;/g' list_of_files
    make format

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8751

Test Plan: existing

Reviewed By: zhichao-cao

Differential Revision: D30745277

Pulled By: pdillinger

fbshipit-source-id: 6f65f0631c3563382d43347896020413cc2366d9
2021-09-07 11:31:59 -07:00
James Yin
7ddc096d7d Fix typo in the comment of log_empty_ (#8711)
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/8711

Reviewed By: riversand963

Differential Revision: D30566761

Pulled By: jay-zhuang

fbshipit-source-id: dd4690f5e2af2d263ed75ea1b9ed24692fe81362
2021-08-27 12:10:29 -07:00
Peter Dillinger
b6269b078a Stable cache keys on ingested SST files (#8669)
Summary:
Extends https://github.com/facebook/rocksdb/issues/8659 to work for ingested external SST files, even
the same file ingested into different DBs sharing a block cache.

Note: These new cache keys are currently only enabled when FileSystem
does not provide GetUniqueId. For now, they are typically larger,
so slightly less efficient.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8669

Test Plan: Extended unit test

Reviewed By: zhichao-cao

Differential Revision: D30398532

Pulled By: pdillinger

fbshipit-source-id: 1f13e2af4b8bfff5741953a69466e9589fbc23c7
2021-08-18 11:33:03 -07:00
Merlin Mao
f58d276764 Make TraceRecord and Replayer public (#8611)
Summary:
New public interfaces:
`TraceRecord` and `TraceRecord::Handler`, available in "rocksdb/trace_record.h".
`Replayer`, available in `rocksdb/utilities/replayer.h`.

User can use `DB::NewDefaultReplayer()` to create a Replayer to auto/manual replay a trace file.

Unit tests:
- `./db_test2 --gtest_filter="DBTest2.TraceAndReplay"`: Updated with the internal API changes.
- `./db_test2 --gtest_filter="DBTest2.TraceAndManualReplay"`: New for manual replay.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8611

Reviewed By: ajkr

Differential Revision: D30266329

Pulled By: autopear

fbshipit-source-id: 1ecb3cbbedae0f6a67c18f0cc82e002b4d81b6f8
2021-08-11 19:32:46 -07:00
longlijian
803a40d412 Delete legacy code not used any more. (#8508)
Summary:
The removed function in this PR,  just only have declared and dose not have any reference used.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8508

Reviewed By: mrambacher

Differential Revision: D29649033

Pulled By: jay-zhuang

fbshipit-source-id: df98143b73d6c184a2a60c9f7ea2548a065ee35d
2021-07-14 16:04:56 -07:00
Baptiste Lemaire
837705ad80 Make mempurge a background process (equivalent to in-memory compaction). (#8505)
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
2021-07-09 17:23:59 -07:00
longlijian
ac3f3f3719 Eliminate compiler complaining, which the return type of the function… (#8498)
Summary:
… should be uint64_t.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8498

Reviewed By: jay-zhuang

Differential Revision: D29605064

Pulled By: ajkr

fbshipit-source-id: e431448ac9d8a37ae83679c4cc5732e29fe49de4
2021-07-08 10:09:05 -07:00
Baptiste Lemaire
9dc887ece0 Memtable "MemPurge" prototype (#8454)
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
2021-07-02 05:23:02 -07:00
mrambacher
be219089ad Add BlobMetaData retrieval methods (#8273)
Summary:
Added BlobMetaData to ColumnFamilyMetaData and LiveBlobMetaData and DB API GetLiveBlobMetaData to retrieve it.

First pass at struct.  More tests and maybe fields to come...

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8273

Reviewed By: ltamasi

Differential Revision: D29102400

Pulled By: mrambacher

fbshipit-source-id: 8a2383a4446328be6b91dced9841fdd3dfc80b73
2021-06-28 08:13:29 -07:00
David Devecsery
80a59a03a7 Cancel compact range (#8351)
Summary:
Added the ability to cancel an in-progress range compaction by storing to an atomic "canceled" variable pointed to within the CompactRangeOptions structure.

Tested via two tests added to db_tests2.cc.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8351

Reviewed By: ajkr

Differential Revision: D28808894

Pulled By: ddevec

fbshipit-source-id: cb321361c9e23b084b188bb203f11c375a22c2dd
2021-06-07 11:41:31 -07:00
Jay Zhuang
f0fca2b1d5 Add internal compaction API for Secondary instance (#8171)
Summary:
Add compaction API for secondary instance, which compact the files to a secondary DB path without installing to the LSM tree.
The API will be used to remote compaction.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8171

Test Plan: `make check`

Reviewed By: ajkr

Differential Revision: D27694545

Pulled By: jay-zhuang

fbshipit-source-id: 8ff3ec1bffdb2e1becee994918850c8902caf731
2021-04-22 13:02:28 -07:00
Akanksha Mahajan
596e9008e4 Stall writes in WriteBufferManager when memory_usage exceeds buffer_size (#7898)
Summary:
When WriteBufferManager is shared across DBs and column families
to maintain memory usage under a limit, OOMs have been observed when flush cannot
finish but writes continuously insert to memtables.
In order to avoid OOMs, when memory usage goes beyond buffer_limit_ and DBs tries to write,
this change will stall incoming writers until flush is completed and memory_usage
drops.

Design: Stall condition: When total memory usage exceeds WriteBufferManager::buffer_size_
(memory_usage() >= buffer_size_) WriterBufferManager::ShouldStall() returns true.

DBImpl first block incoming/future writers by calling write_thread_.BeginWriteStall()
(which adds dummy stall object to the writer's queue).
Then DB is blocked on a state State::Blocked (current write doesn't go
through). WBStallInterface object maintained by every DB instance is added to the queue of
WriteBufferManager.

If multiple DBs tries to write during this stall, they will also be
blocked when check WriteBufferManager::ShouldStall() returns true.

End Stall condition: When flush is finished and memory usage goes down, stall will end only if memory
waiting to be flushed is less than buffer_size/2. This lower limit will give time for flush
to complete and avoid continous stalling if memory usage remains close to buffer_size.

WriterBufferManager::EndWriteStall() is called,
which removes all instances from its queue and signal them to continue.
Their state is changed to State::Running and they are unblocked. DBImpl
then signal all incoming writers of that DB to continue by calling
write_thread_.EndWriteStall() (which removes dummy stall object from the
queue).

DB instance creates WBMStallInterface which is an interface to block and
signal DBs during stall.
When DB needs to be blocked or signalled by WriteBufferManager,
state_for_wbm_ state is changed accordingly (RUNNING or BLOCKED).

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7898

Test Plan: Added a new test db/db_write_buffer_manager_test.cc

Reviewed By: anand1976

Differential Revision: D26093227

Pulled By: akankshamahajan15

fbshipit-source-id: 2bbd982a3fb7033f6de6153aa92a221249861aae
2021-04-21 13:54:02 -07:00
Giuseppe Ottaviano
48cd7a3aae Fix flush reason attribution (#8150)
Summary:
Current flush reason attribution is misleading or incorrect (depending on what the original intention was):

- Flush due to WAL reaching its maximum size is attributed to `kWriteBufferManager`
- Flushes due to full write buffer and write buffer manager are not distinguishable, both are attributed to `kWriteBufferFull`

This changes the first to a new flush reason `kWALFull`, and splits the second between `kWriteBufferManager` and `kWriteBufferFull`.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8150

Reviewed By: zhichao-cao

Differential Revision: D27569645

Pulled By: ot

fbshipit-source-id: 7e3c8ca186a6e71976e6b8e937297eebd4b769cc
2021-04-07 23:18:37 -07:00
Peter Dillinger
879357fdb0 Make backups openable as read-only DBs (#8142)
Summary:
A current limitation of backups is that you don't know the
exact database state of when the backup was taken. With this new
feature, you can at least inspect the backup's DB state without
restoring it by opening it as a read-only DB.

Rather than add something like OpenAsReadOnlyDB to the BackupEngine API,
which would inhibit opening stackable DB implementations read-only
(if/when their APIs support it), we instead provide a DB name and Env
that can be used to open as a read-only DB.

Possible follow-up work:

* Add a version of GetBackupInfo for a single backup.
* Let CreateNewBackup return the BackupID of the newly-created backup.

Implementation details:

Refactored ChrootFileSystem to split off new base class RemapFileSystem,
which allows more general remapping of files. We use this base class to
implement BackupEngineImpl::RemapSharedFileSystem.

To minimize API impact, I decided to just add these fields `name_for_open`
and `env_for_open` to those set by GetBackupInfo when
include_file_details=true. Creating the RemapSharedFileSystem adds a bit
to the memory consumption, perhaps unnecessarily in some cases, but this
has been mitigated by (a) only initialize the RemapSharedFileSystem
lazily when GetBackupInfo with include_file_details=true is called, and
(b) using the existing `shared_ptr<FileInfo>` objects to hold most of the
mapping data.

To enhance API safety, RemapSharedFileSystem is wrapped by new
ReadOnlyFileSystem which rejects any attempts to write. This uncovered a
couple of places in which DB::OpenForReadOnly would write to the
filesystem, so I fixed these. Added a release note because this affects
logging.

Additional minor refactoring in backupable_db.cc to support the new
functionality.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8142

Test Plan:
new test (run with ASAN and UBSAN), added to stress test and
ran it for a while with amplified backup_one_in

Reviewed By: ajkr

Differential Revision: D27535408

Pulled By: pdillinger

fbshipit-source-id: 04666d310aa0261ef6b2385c43ca793ce1dfd148
2021-04-06 14:37:53 -07:00
Akanksha Mahajan
689b13e639 Add request_id in IODebugContext. (#8045)
Summary:
Add request_id in IODebugContext which will be populated by
    underlying FileSystem for IOTracing purposes. Update IOTracer to trace
    request_id in the tracing records. Provided API
    IODebugContext::SetRequestId which will set the request_id and enable
    tracing for request_id. The API hides the implementation and underlying
    file system needs to call this API directly.

Update DB::StartIOTrace API and remove redundant Env* from the
    argument as its not used and DB already has Env that is passed down to
    IOTracer.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8045

Test Plan: Update unit test.

Differential Revision: D26899871

Pulled By: akankshamahajan15

fbshipit-source-id: 56adef52ee5af0fb3060b607c3af1ec01635fa2b
2021-04-01 13:14:51 -07:00
sherriiiliu
e6534900bd Fix possible hang issue in ~DBImpl() when flush is scheduled in LOW pool (#8125)
Summary:
In DBImpl::CloseHelper, we wait for bg_compaction_scheduled_
and bg_flush_scheduled_ to drop to 0. Unschedule is called prior
to cancel any unscheduled flushes/compactions. It is assumed that
anything in the high priority is a flush, and anything in the low
priority pool is a compaction. This assumption, however, is broken when
the high-pri pool is full.
As a result, bg_compaction_scheduled_ can go < 0 and bg_flush_scheduled_
will remain > 0 and DB can be in hang state.
The fix is, we decrement the `bg_{flush,compaction,bottom_compaction}_scheduled_`
inside the `Unschedule{Flush,Compaction,BottomCompaction}Callback()`s. DB
`mutex_` will make the counts atomic in `Unschedule`.
Related discussion: https://github.com/facebook/rocksdb/issues/7928

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8125

Test Plan: Added new test case which hangs without the fix.

Reviewed By: jay-zhuang

Differential Revision: D27390043

Pulled By: ajkr

fbshipit-source-id: 78a367fba9a59ac5607ad24bd1c46dc16d5ec110
2021-03-30 18:35:20 -07:00
anand76
7d7f14480e Always truncate the latest WAL file on DB Open (#8122)
Summary:
Currently, we only truncate the latest alive WAL files when the DB is opened. If the latest WAL file is empty or was flushed during Open, its not truncated since the file will be deleted later on in the Open path. However, before deletion, a new WAL file is created, and if the process crash loops between the new WAL file creation and deletion of the old WAL file, the preallocated space will keep accumulating and eventually use up all disk space. To prevent this, always truncate the latest WAL file, even if its empty or the data was flushed.

Tests:
Add unit tests to db_wal_test

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8122

Reviewed By: riversand963

Differential Revision: D27366132

Pulled By: anand1976

fbshipit-source-id: f923cc03ef033ccb32b140d36c6a63a8152f0e8e
2021-03-28 10:00:08 -07:00
Akanksha Mahajan
27d57a035e Use SST file manager to track blob files as well (#8037)
Summary:
Extend support to track blob files in SST File manager.
 This PR notifies SstFileManager whenever a new blob file is created,
 via OnAddFile and  an obsolete blob file deleted via OnDeleteFile
 and delete file via ScheduleFileDeletion.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8037

Test Plan: Add new unit tests

Reviewed By: ltamasi

Differential Revision: D26891237

Pulled By: akankshamahajan15

fbshipit-source-id: 04c69ccfda2a73782fd5c51982dae58dd11979b6
2021-03-17 20:44:49 -07:00
mrambacher
3dff28cf9b Use SystemClock* instead of std::shared_ptr<SystemClock> in lower level routines (#8033)
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
2021-03-15 04:34:11 -07:00
Akanksha Mahajan
46cf5fbfdd Extend VerifyFileChecksums API for blob files (#7979)
Summary:
Extend VerifyFileChecksums API to verify blob files in case of
use_file_checksum.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7979

Test Plan: New unit test db_blob_corruption_test

Reviewed By: ltamasi

Differential Revision: D26534040

Pulled By: akankshamahajan15

fbshipit-source-id: 7dc5951a3df9d265ea1265e0122b43c966856ade
2021-02-22 22:09:22 -08:00
Zhichao Cao
b0fd1cc45a Introduce a new trace file format (v 0.2) for better extension (#7977)
Summary:
The trace file record and payload encode is fixed, which requires complex backward compatibility resolving. This PR introduce a new trace file format, which makes it easier to add new entries to the payload and does not have backward compatible issues. V 0.1 is still supported in this PR. Added the tracing for lower_bound and upper_bound for iterator.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7977

Test Plan: make check. tested with old trace file in replay and analyzing.

Reviewed By: anand1976

Differential Revision: D26529948

Pulled By: zhichao-cao

fbshipit-source-id: ebb75a127ce3c07c25a1ccc194c551f917896a76
2021-02-18 23:05:35 -08:00