Commit Graph

142 Commits

Author SHA1 Message Date
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
anand76
3362a730dc Avoid usage of ReopenWritableFile in db_stress (#9649)
Summary:
The UniqueIdVerifier constructor currently calls ReopenWritableFile on
the FileSystem, which might not be supported. Instead of relying on
reopening the unique IDs file for writing, create a new file and copy
the original contents.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9649

Test Plan: Run db_stress

Reviewed By: pdillinger

Differential Revision: D34572307

Pulled By: anand1976

fbshipit-source-id: 3a777908582d79dae57488d4278bad126774f698
2022-03-04 10:30:10 -08:00
Jay Zhuang
d3a2f284d9 Add Temperature info in NewSequentialFile() (#9499)
Summary:
Add Temperature hints information from RocksDB in API
`NewSequentialFile()`. backup and checkpoint operations need to open the
source files with `NewSequentialFile()`, which will have the temperature
hints. Other operations are not covered.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9499

Test Plan: Added unittest

Reviewed By: pdillinger

Differential Revision: D34006115

Pulled By: jay-zhuang

fbshipit-source-id: 568b34602b76520e53128672bd07e9d886786a2f
2022-02-18 18:23:07 -08:00
Jay Zhuang
f4b2500e12 Add last level and non-last level read statistics (#9519)
Summary:
Add last level and non-last level read statistics:
```
LAST_LEVEL_READ_BYTES,
LAST_LEVEL_READ_COUNT,
NON_LAST_LEVEL_READ_BYTES,
NON_LAST_LEVEL_READ_COUNT,
```

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9519

Test Plan: added unittest

Reviewed By: siying

Differential Revision: D34062539

Pulled By: jay-zhuang

fbshipit-source-id: 908644c3050878b4234febdc72e3e19d89af38cd
2022-02-18 14:23:07 -08:00
Jay Zhuang
2fbc672732 Add temperature information to the event listener callbacks (#9591)
Summary:
RocksDB try to provide temperature information in the event
listener callbacks. The information is not guaranteed, as some operation
like backup won't have these information.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9591

Test Plan: Added unittest

Reviewed By: siying, pdillinger

Differential Revision: D34309339

Pulled By: jay-zhuang

fbshipit-source-id: 4aca4f270f99fa49186d85d300da42594663d6d7
2022-02-18 11:23:18 -08:00
Andrew Kryczka
babe56ddba Add rate limiter priority to ReadOptions (#9424)
Summary:
Users can set the priority for file reads associated with their operation by setting `ReadOptions::rate_limiter_priority` to something other than `Env::IO_TOTAL`. Rate limiting `VerifyChecksum()` and `VerifyFileChecksums()` is the motivation for this PR, so it also includes benchmarks and minor bug fixes to get that working.

`RandomAccessFileReader::Read()` already had support for rate limiting compaction reads. I changed that rate limiting to be non-specific to compaction, but rather performed according to the passed in `Env::IOPriority`. Now the compaction read rate limiting is supported by setting `rate_limiter_priority = Env::IO_LOW` on its `ReadOptions`.

There is no default value for the new `Env::IOPriority` parameter to `RandomAccessFileReader::Read()`. That means this PR goes through all callers (in some cases multiple layers up the call stack) to find a `ReadOptions` to provide the priority. There are TODOs for cases I believe it would be good to let user control the priority some day (e.g., file footer reads), and no TODO in cases I believe it doesn't matter (e.g., trace file reads).

The API doc only lists the missing cases where a file read associated with a provided `ReadOptions` cannot be rate limited. For cases like file ingestion checksum calculation, there is no API to provide `ReadOptions` or `Env::IOPriority`, so I didn't count that as missing.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9424

Test Plan:
- new unit tests
- new benchmarks on ~50MB database with 1MB/s read rate limit and 100ms refill interval; verified with strace reads are chunked (at 0.1MB per chunk) and spaced roughly 100ms apart.
  - setup command: `./db_bench -benchmarks=fillrandom,compact -db=/tmp/testdb -target_file_size_base=1048576 -disable_auto_compactions=true -file_checksum=true`
  - benchmarks command: `strace -ttfe pread64 ./db_bench -benchmarks=verifychecksum,verifyfilechecksums -use_existing_db=true -db=/tmp/testdb -rate_limiter_bytes_per_sec=1048576 -rate_limit_bg_reads=1 -rate_limit_user_ops=true -file_checksum=true`
- crash test using IO_USER priority on non-validation reads with https://github.com/facebook/rocksdb/issues/9567 reverted: `python3 tools/db_crashtest.py blackbox --max_key=1000000 --write_buffer_size=524288 --target_file_size_base=524288 --level_compaction_dynamic_level_bytes=true --duration=3600 --rate_limit_bg_reads=true --rate_limit_user_ops=true --rate_limiter_bytes_per_sec=10485760 --interval=10`

Reviewed By: hx235

Differential Revision: D33747386

Pulled By: ajkr

fbshipit-source-id: a2d985e97912fba8c54763798e04f006ccc56e0c
2022-02-16 23:18:14 -08:00
Yanqin Jin
dd203ed604 Disallow a combination of options (#9348)
Summary:
Disallow `immutable_db_opts.use_direct_io_for_flush_and_compaction == true` and
`mutable_db_opts.writable_file_max_buffer_size == 0`, since it causes `WritableFileWriter::Append()`
to loop forever and does not make much sense in direct IO.

This combination of options itself does not make much sense: asking RocksDB to do direct IO but not allowing
RocksDB to allocate a buffer. We should detect this false combination and warn user early, no matter whether
the application is running on a platform that supports direct IO or not. In the case of platform **not** supporting
direct IO, it's ok if the user learns about this and then finds that direct IO is not supported.

One tricky thing: the constructor of `WritableFileWriter` is being used in our unit tests, and it's impossible
to return status code from constructor. Since we do not throw, I put an assertion for now. Fortunately,
the constructor is not exposed to external applications.

Closing https://github.com/facebook/rocksdb/issues/7109

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9348

Test Plan: make check

Reviewed By: ajkr

Differential Revision: D33371924

Pulled By: riversand963

fbshipit-source-id: 2a3701ab541cee23bffda8a36cdf37b2d235edfa
2022-01-27 19:30:24 -08:00
anand76
beb86addeb Fix race condition in SstFileManagerImpl error recovery code (#9435)
Summary:
There is a race in SstFileManagerImpl between the ClearError() function
and CancelErrorRecovery(). The race can cause ClearError() to deref the
file system pointer after it has been freed. This is likely to occur
during process shutdown, when the order of destruction of the
DB/Env/FileSystem and SstFileManagerImpl is not deterministic.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9435

Test Plan:
Reproduce the crash in a TSAN build by introducing sleeps in the code, and verify with
the fix.

Reviewed By: siying

Differential Revision: D33774696

Pulled By: anand1976

fbshipit-source-id: 643d3da31b8d2ee6d9b6db5d33327e0053ce3b83
2022-01-25 23:22:58 -08:00
Yanqin Jin
08721293ea Fix a bug causing duplicate trailing entries in WritableFile (buffered IO) (#9236)
Summary:
`db_stress` is a user of `FaultInjectionTestFS`. After injecting a write error, `db_stress` probabilistically determins
data drop (https://github.com/facebook/rocksdb/blob/6.27.fb/db_stress_tool/db_stress_test_base.cc#L2615:L2619).

In some of our recent runs of `db_stress`, we found duplicate trailing entries corresponding to file trivial move in
the MANIFEST, causing the recovery to fail, because the file move operation is not idempotent: you cannot delete a
file from a given level twice.

Investigation suggests that data buffering in both `WritableFileWriter` and `FaultInjectionTestFS` may be the root cause.

WritableFileWriter buffers data to write in a memory buffer, `WritableFileWriter::buf_`. After each
`WriteBuffered()`/`WriteBufferedWithChecksum()` succeeds, the `buf_` is cleared.

If the underlying file `WritableFileWriter::writable_file_` is opened in buffered IO mode, then `FaultInjectionTestFS`
buffers data written for each file until next file sync. After an injected error, user of `FaultInjectionFS` can
choose to drop some or none of previously buffered data. If `db_stress` does not drop any unsynced data, then
such data will still exist in the `FaultInjectionTestFS`'s buffer.

Existing implementation of `WritableileWriter::WriteBuffered()` does not clear `buf_` if there is an error. This may lead
to the data being buffered two copies: one in `WritableFileWriter`, and another in `FaultInjectionTestFS`.
We also know that the `WritableFileWriter` of MANIFEST file will close upon an error.  During `Close()`, it will flush the
content in `buf_`. If no write error is injected to `FaultInjectionTestFS` this time, then we end up with two copies of the
data appended to the file.

To fix, we clear the `WritableFileWriter::buf_` upon failure as well. We focus this PR on files opened in non-direct mode.

This PR includes a unit test to reproduce a case when write error injection
to `WritableFile` can cause duplicate trailing entries.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9236

Test Plan: make check

Reviewed By: zhichao-cao

Differential Revision: D33033984

Pulled By: riversand963

fbshipit-source-id: ebfa5a0db8cbf1ed73100528b34fcba543c5db31
2021-12-13 09:00:36 -08:00
Akanksha Mahajan
04b2c16f9b Fix bug in rocksdb internal automatic prefetching (#9234)
Summary:
After introducing adaptive_readahead, the original flow got
broken. Readahead size was set to 0 because of which rocksdb wasn't be
able to do automatic prefetching which it enables after seeing
sequential reads. This PR fixes it.

----------------------------------------------------------------------------------------------------

Before this patch:
b_bench -use_existing_db=true -db=/tmp/prefix_scan -benchmarks="seekrandom" -key_size=32 -value_size=512 -num=5000000 -use_direct_reads=true -seek_nexts=327680 -duration=120 -ops_between_duration_checks=1
Initializing RocksDB Options from the specified file
Initializing RocksDB Options from command-line flags
RocksDB:    version 6.27
Date:       Tue Nov 30 11:56:50 2021
CPU:        24 * Intel Core Processor (Broadwell)
CPUCache:   16384 KB
Keys:       32 bytes each (+ 0 bytes user-defined timestamp)
Values:     512 bytes each (256 bytes after compression)
Entries:    5000000
Prefix:    0 bytes
Keys per prefix:    0
RawSize:    2594.0 MB (estimated)
FileSize:   1373.3 MB (estimated)
Write rate: 0 bytes/second
Read rate: 0 ops/second
Compression: Snappy
Compression sampling rate: 0
Memtablerep: SkipListFactory
Perf Level: 1
WARNING: Assertions are enabled; benchmarks unnecessarily slow
------------------------------------------------
DB path: [/tmp/prefix_scan]

seekrandom   : 5356367.174 micros/op 0 ops/sec;   29.4 MB/s (23 of 23 found)

----------------------------------------------------------------------------------------------------

After the patch:
./db_bench -use_existing_db=true -db=/tmp/prefix_scan -benchmarks="seekrandom" -key_size=32 -value_size=512 -num=5000000 -use_direct_reads=true -seek_nexts=327680 -duration=120 -ops_between_duration_checks=1
Initializing RocksDB Options from the specified file
Initializing RocksDB Options from command-line flags
RocksDB:    version 6.27
Date:       Tue Nov 30 14:38:33 2021
CPU:        24 * Intel Core Processor (Broadwell)
CPUCache:   16384 KB
Keys:       32 bytes each (+ 0 bytes user-defined timestamp)
Values:     512 bytes each (256 bytes after compression)
Entries:    5000000
Prefix:    0 bytes
Keys per prefix:    0
RawSize:    2594.0 MB (estimated)
FileSize:   1373.3 MB (estimated)
Write rate: 0 bytes/second
Read rate: 0 ops/second
Compression: Snappy
Compression sampling rate: 0
Memtablerep: SkipListFactory
Perf Level: 1
WARNING: Assertions are enabled; benchmarks unnecessarily slow
------------------------------------------------
DB path: [/tmp/prefix_scan]
seekrandom   :  456504.277 micros/op 2 ops/sec;  359.8 MB/s (264 of 264 found)

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9234

Test Plan:
Ran ./db_bench -db=/data/mysql/rocksdb/prefix_scan
-benchmarks="fillseq" -key_size=32 -value_size=512 -num=5000000 -use_d
irect_io_for_flush_and_compaction=true -target_file_size_base=16777216
and then ./db_bench -use_existing_db=true
-db=/data/mysql/rocksdb/prefix_scan -benchmarks="seekrandom"
-key_size=32 -value_siz
e=512 -num=5000000 -use_direct_reads=true -seek_nexts=327680
-duration=120 -ops_between_duration_checks=1
 and compared the results.

Reviewed By: anand1976

Differential Revision: D32743965

Pulled By: akankshamahajan15

fbshipit-source-id: b950fba68c91963b7deb5c20acdf471bc60251f5
2021-11-30 22:53:10 -08:00
Levi Tamasi
dc5de45af8 Support readahead during compaction for blob files (#9187)
Summary:
The patch adds a new BlobDB configuration option `blob_compaction_readahead_size`
that can be used to enable prefetching data from blob files during compaction.
This is important when using storage with higher latencies like HDDs or remote filesystems.
If enabled, prefetching is used for all cases when blobs are read during compaction,
namely garbage collection, compaction filters (when the existing value has to be read from
a blob file), and `Merge` (when the value of the base `Put` is stored in a blob file).

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9187

Test Plan: Ran `make check` and the stress/crash test.

Reviewed By: riversand963

Differential Revision: D32565512

Pulled By: ltamasi

fbshipit-source-id: 87be9cebc3aa01cc227bec6b5f64d827b8164f5d
2021-11-19 17:53:47 -08:00
Akanksha Mahajan
4a7c1dc375 Add listener API that notifies on IOError (#9177)
Summary:
Add a new API in listener.h that notifies about IOErrors on
Read/Write/Append/Flush etc. The API reports about IOStatus, filename, Operation
name, offset and length.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9177

Test Plan: Added new unit tests

Reviewed By: anand1976

Differential Revision: D32470627

Pulled By: akankshamahajan15

fbshipit-source-id: 189a717033590ae227b3beae8b1e7e185e4cdc12
2021-11-18 17:11:19 -08:00
Zhichao Cao
b694cd0e0d Add tiered storage related read bytes stats to Statistic (#9123)
Summary:
Add the 3 read bytes counter to the Statistic, which will be used by storage tiering and get the information for files with different temperature.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9123

Test Plan: added new testing cases.

Reviewed By: siying

Differential Revision: D32154745

Pulled By: zhichao-cao

fbshipit-source-id: b7905d6dae469a72428742364ec07b634b6f15da
2021-11-16 15:17:17 -08:00
Akanksha Mahajan
17ce1ca48b Reuse internal auto readhead_size at each Level (expect L0) for Iterations (#9056)
Summary:
RocksDB does auto-readahead for iterators on noticing more than two sequential reads for a table file if user doesn't provide readahead_size. The readahead starts at 8KB and doubles on every additional read up to max_auto_readahead_size. However at each level, if iterator moves over next file, readahead_size starts again from 8KB.

This PR introduces a new ReadOption "adaptive_readahead" which when set true will maintain readahead_size  at each level. So when iterator moves from one file to another, new file's readahead_size will continue from previous file's readahead_size instead of scratch. However if reads are not sequential it will fall back to 8KB (default) with no prefetching for that block.

1. If block is found in cache but it was eligible for prefetch (block wasn't in Rocksdb's prefetch buffer),  readahead_size will decrease by 8KB.
2. It maintains readahead_size for L1 - Ln levels.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9056

Test Plan:
Added new unit tests
Ran db_bench for "readseq, seekrandom, seekrandomwhilewriting, readrandom" with --adaptive_readahead=true and there was no regression if new feature is enabled.

Reviewed By: anand1976

Differential Revision: D31773640

Pulled By: akankshamahajan15

fbshipit-source-id: 7332d16258b846ae5cea773009195a5af58f8f98
2021-11-10 16:20:04 -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
mrambacher
f72c834eab Make FileSystem a Customizable Class (#8649)
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/8649

Reviewed By: zhichao-cao

Differential Revision: D32036059

Pulled By: mrambacher

fbshipit-source-id: 4f1e7557ecac52eb849b83ae02b8d7d232112295
2021-11-02 09:07:11 -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
Zhichao Cao
b632ed0c67 Add file temperature related counter and bytes stats to and io_stats (#8710)
Summary:
For tiered storage project, we need to know the block read count and read bytes of files with different temperature. Add FileIOByTemperature to IOStatsContext and collect the bytes read and read count from different temperature files through the RandomAccessFileReader.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8710

Test Plan: make check, add the testing cases

Reviewed By: siying

Differential Revision: D30582400

Pulled By: zhichao-cao

fbshipit-source-id: d83173de594374fc8404af5ce93a6a9be72c7141
2021-10-07 14:58:41 -07:00
Zhichao Cao
699f45049d Introduce a mechanism to dump out blocks from block cache and re-insert to secondary cache (#8912)
Summary:
Background: Cache warming up will cause potential read performance degradation due to reading blocks from storage to the block cache. Since in production, the workload and access pattern to a certain DB is stable, it is a potential solution to dump out the blocks belonging to a certain DB to persist storage (e.g., to a file) and bulk-load the blocks to Secondary cache before the DB is relaunched. For example, when migrating a DB form host A to host B, it will take a short period of time, the access pattern to blocks in the block cache will not change much. It is efficient to dump out the blocks of certain DB, migrate to the destination host and insert them to the Secondary cache before we relaunch the DB.

Design: we introduce the interface of CacheDumpWriter and CacheDumpRead for user to store the blocks dumped out from block cache. RocksDB will encode all the information and send the string to the writer. User can implement their own writer it they want. CacheDumper and CacheLoad are introduced to save the blocks and load the blocks respectively.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8912

Test Plan: add new tests to lru_cache_test and pass make check.

Reviewed By: pdillinger

Differential Revision: D31452871

Pulled By: zhichao-cao

fbshipit-source-id: 11ab4f5d03e383f476947116361d54188d36ec48
2021-10-07 11:42:31 -07:00
Stefan Roesch
a776406de3 Add file operation callbacks to SequentialFileReader (#8982)
Summary:
This change adds File IO Notifications to the SequentialFileReader The SequentialFileReader is extended
with a listener parameter.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8982

Test Plan:
A new test EventListenerTest::OnWALOperationTest has been added. The
test verifies that during restore the sequential file reader is called
and the notifications are fired.

Reviewed By: riversand963

Differential Revision: D31320844

Pulled By: shrfb

fbshipit-source-id: 040b24da7c010d7c14ebb5c6460fae9a19b8c168
2021-10-05 10:51:59 -07:00
sdong
7f08a8503f Remove IOSTATS_ADD_IF_POSITIVE() (#8984)
Summary:
IOSTATS_ADD_IF_POSITIVE() doesn't seem to a macro that aims to improve performance but does the opposite. The counter to add is almost always positive so the if is just a waste. Furthermore, adding to a thread local variable seemse to be much cheaper than an if condition if branch prediction has a possibility to be wrong. Remove the macro.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8984

Test Plan: See CI completes.

Reviewed By: anand1976

Differential Revision: D31348163

fbshipit-source-id: 30af6d45e1aa8bbc09b2c046206cce6f67f4777a
2021-10-01 14:43:00 -07:00
Yanqin Jin
2acffecca1 Add comments for MultiGetBlob() and checks for MultiRead() (#8972)
Summary:
Add comments for MultiGetBlob() that input argument `offsets` must be
sorted. In addition, add assertion for this condition in debug build.
Repeat the same for RandomAccessFileReader::MultiRead().

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8972

Test Plan: make check

Reviewed By: pdillinger

Differential Revision: D31253205

Pulled By: riversand963

fbshipit-source-id: 98758229b8052f3aeb319d5584026b4de2d220a2
2021-09-29 14:27:19 -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
sdong
b88109db19 Pollute buffer before calling Read() (#8955)
Summary:
Add a paranoid check where in case FileSystem layer doesn't fill the buffer but returns succeed, checksum is unlikely to match even if buffer contains a previous block. The byte modified is not useful anyway, so it isn't expect to change any behavior.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8955

Test Plan: See existing CI to pass.

Reviewed By: pdillinger

Differential Revision: D31183966

fbshipit-source-id: dcc4de429e18131873f783b90d3be55d7eb44a1f
2021-09-27 21:30:28 -07:00
sdong
fcce1f2c7a RandomAccessFileReader::MultiRead() should not return read bytes not read (#8941)
Summary:
Right now, if underlying read returns fewer bytes than asked for, RandomAccessFileReader::MultiRead() still returns those in the buffer to upper layer. This can be a surprise to upper layer.
This is unlikely to cause incorrect data. To cause incorrect data, checksum checking in upper layer should pass with short reads, whose chance is low.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8941

Test Plan: Run stress tests for a while

Reviewed By: anand1976

Differential Revision: D31085780

fbshipit-source-id: 999adf2d6c2712f1323d14bb68b678df59969973
2021-09-21 12:22:22 -07:00
Zhichao Cao
82e7631de6 Replace Status with IOStatus in the backupable_db (#8820)
Summary:
In order to populate the IOStatus up to the higher level, replace some of the Status to IOStatus.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8820

Test Plan: make check

Reviewed By: pdillinger

Differential Revision: D30967215

Pulled By: zhichao-cao

fbshipit-source-id: ccf9d5cfbd9d3de047c464aaa85f9fa43b474903
2021-09-15 15:09:48 -07:00
mrambacher
dafa584fd1 Change the File System File Wrappers to std::unique_ptr (#8618)
Summary:
This allows the wrapper classes to own the wrapped object and eliminates confusion as to ownership.  Previously, many classes implemented their own ownership solutions.  Fixes https://github.com/facebook/rocksdb/issues/8606

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8618

Reviewed By: pdillinger

Differential Revision: D30136064

Pulled By: mrambacher

fbshipit-source-id: d0bf471df8818dbb1770a86335fe98f761cca193
2021-09-13 08:46:19 -07:00
Andrew Kryczka
9308ff366c Bytes read/written stats for CreateNewBackup*() (#8819)
Summary:
Gets `Statistics` from the options associated with the `DB` undergoing backup, and populates new ticker stats with the thread-local `IOContext` read/write counters for the threads doing backup work.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8819

Reviewed By: pdillinger

Differential Revision: D30779238

Pulled By: ajkr

fbshipit-source-id: 75ccafc355f90906df5cf80367f7245b985772d8
2021-09-07 18:25:16 -07:00
Adam Retter
5de333fd99 Add db_test2 to to ASSERT_STATUS_CHECKED (#8640)
Summary:
This is the `db_test2` parts of https://github.com/facebook/rocksdb/pull/7737 reworked on the latest HEAD.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8640

Reviewed By: akankshamahajan15

Differential Revision: D30303684

Pulled By: mrambacher

fbshipit-source-id: 263e2f82d849bde4048b60aed8b31e7deed4706a
2021-08-16 08:10:32 -07:00
sdong
e7c24168d8 Move old files to warm tier in FIFO compactions (#8310)
Summary:
Some FIFO users want to keep the data for longer, but the old data is rarely accessed. This feature allows users to configure FIFO compaction so that data older than a threshold is moved to a warm storage tier.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8310

Test Plan: Add several unit tests.

Reviewed By: ajkr

Differential Revision: D28493792

fbshipit-source-id: c14824ea634814dee5278b449ab5c98b6e0b5501
2021-08-09 12:51:14 -07:00
mrambacher
ab7f7c9e49 Allow WAL dir to change with db dir (#8582)
Summary:
Prior to this change, the "wal_dir"  DBOption would always be set (defaults to dbname) when the DBOptions were sanitized.  Because of this setitng in the options file, it was not possible to rename/relocate a database directory after it had been created and use the existing options file.

After this change, the "wal_dir" option is only set under specific circumstances.  Methods were added to the ImmutableDBOptions class to see if it is set and if it is set to something other than the dbname.  Additionally, a method was added to retrieve the effective value of the WAL dir (either the option or the dbname/path).

Tests were added to the core and ldb to test that a database could be created and renamed without issue.  Additional tests for various permutations of wal_dir were also added.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8582

Reviewed By: pdillinger, autopear

Differential Revision: D29881122

Pulled By: mrambacher

fbshipit-source-id: 67d3d033dc8813d59917b0a3fba2550c0efd6dfb
2021-07-30 12:16:44 -07:00
Drewryz
3b27725245 Fix a minor issue with initializing the test path (#8555)
Summary:
The PerThreadDBPath has already specified a slash. It does not need to be specified when initializing the test path.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8555

Reviewed By: ajkr

Differential Revision: D29758399

Pulled By: jay-zhuang

fbshipit-source-id: 6d2b878523e3e8580536e2829cb25489844d9011
2021-07-23 08:38:45 -07:00
Zhichao Cao
87e82a41a9 Fix incorrect Status::NoSpace() status check (#8504)
Summary:
If we want to check whether a Status s is NoSpace() or not, we should check the subcode instread of using s==Status::NoSpace(). Fix some of the incorrect check in the ErrorHandler.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8504

Test Plan: make check

Reviewed By: anand1976

Differential Revision: D29601764

Pulled By: zhichao-cao

fbshipit-source-id: cdab56a827891c23746bba9cbb53f169fe35f086
2021-07-20 18:09:51 -07:00
Zhichao Cao
a904c62d28 Using existing crc32c checksum in checksum handoff for Manifest and WAL (#8412)
Summary:
In PR https://github.com/facebook/rocksdb/issues/7523 , checksum handoff is introduced in RocksDB for WAL, Manifest, and SST files. When user enable checksum handoff for a certain type of file, before the data is written to the lower layer storage system, we calculate the checksum (crc32c) of each piece of data and pass the checksum down with the data, such that data verification can be down by the lower layer storage system if it has the capability. However, it cannot cover the whole lifetime of the data in the memory and also it potentially introduces extra checksum calculation overhead.

In this PR, we introduce a new interface in WritableFileWriter::Append, which allows the caller be able to pass the data and the checksum (crc32c) together. In this way, WritableFileWriter can directly use the pass-in checksum (crc32c) to generate the checksum of data being passed down to the storage system. It saves the calculation overhead and achieves higher protection coverage. When a new checksum is added with the data, we use Crc32cCombine https://github.com/facebook/rocksdb/issues/8305 to combine the existing checksum and the new checksum. To avoid the segmenting of data by rate-limiter before it is stored, rate-limiter is called enough times to accumulate enough credits for a certain write. This design only support Manifest and WAL which use log_writer in the current stage.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8412

Test Plan: make check, add new testing cases.

Reviewed By: anand1976

Differential Revision: D29151545

Pulled By: zhichao-cao

fbshipit-source-id: 75e2278c5126cfd58393c67b1efd18dcc7a30772
2021-06-25 00:47:17 -07:00
sdong
e19908cba6 Refactor kill point (#8241)
Summary:
Refactor kill point to one single class, rather than several extern variables. The intention was to drop unflushed data before killing to simulate some job, and I tried to a pointer to fault ingestion fs to the killing class, but it ended up with harder than I thought. Perhaps we'll need to do this in another way. But I thought the refactoring itself is good so I send it out.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8241

Test Plan: make release and run crash test for a while.

Reviewed By: anand1976

Differential Revision: D28078486

fbshipit-source-id: f9182c1455f52e6851c13f88a21bade63bcec45f
2021-05-05 15:50:29 -07:00
mrambacher
8948dc8524 Make ImmutableOptions struct that inherits from ImmutableCFOptions and ImmutableDBOptions (#8262)
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
2021-05-05 14:00:17 -07:00
Akanksha Mahajan
a0e0feca62 Improve BlockPrefetcher to prefetch only for sequential scans (#7394)
Summary:
BlockPrefetcher is used by iterators to prefetch data if they
anticipate more data to be used in future and this is valid for forward sequential
scans. But BlockPrefetcher tracks only num_file_reads_ and not if reads
are sequential. This presents problem for MultiGet with large number of
keys when it reseeks index iterator and data block. FilePrefetchBuffer
can end up doing large readahead for reseeks as readahead size
increases exponentially once readahead is enabled. Same issue is with
BlockBasedTableIterator.

Add previous length and offset read as well in BlockPrefetcher (creates
FilePrefetchBuffer) and FilePrefetchBuffer (does prefetching of data) to
determine if reads are sequential and then  prefetch.

Update the last block read after cache hit to take reads from cache also
in account.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7394

Test Plan: Add new unit test case

Reviewed By: anand1976

Differential Revision: D23737617

Pulled By: akankshamahajan15

fbshipit-source-id: 8e6917c25ed87b285ee495d1b68dc623d71205a3
2021-04-28 12:53:46 -07:00
Yanqin Jin
a376c22066 Handle rename() failure in non-local FS (#8192)
Summary:
In a distributed environment, a file `rename()` operation can succeed on server (remote)
side, but the client can somehow return non-ok status to RocksDB. Possible reasons include
network partition, connection issue, etc. This happens in `rocksdb::SetCurrentFile()`, which
can be called in `LogAndApply() -> ProcessManifestWrites()` if RocksDB tries to switch to a
new MANIFEST. We currently always delete the new MANIFEST if an error occurs.

This is problematic in distributed world. If the server-side successfully updates the CURRENT
file via renaming, then a subsequent `DB::Open()` will try to look for the new MANIFEST and fail.

As a fix, we can track the execution result of IO operations on the new MANIFEST.
- If IO operations on the new MANIFEST fail, then we know the CURRENT must point to the original
  MANIFEST. Therefore, it is safe to remove the new MANIFEST.
- If IO operations on the new MANIFEST all succeed, but somehow we end up in the clean up
  code block, then we do not know whether CURRENT points to the new or old MANIFEST. (For local
  POSIX-compliant FS, it should still point to old MANIFEST, but it does not matter if we keep the
  new MANIFEST.) Therefore, we keep the new MANIFEST.
    - Any future `LogAndApply()` will switch to a new MANIFEST and update CURRENT.
    - If process reopens the db immediately after the failure, then the CURRENT file can point
      to either the new MANIFEST or the old one, both of which exist. Therefore, recovery can
      succeed and ignore the other.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8192

Test Plan: make check

Reviewed By: zhichao-cao

Differential Revision: D27804648

Pulled By: riversand963

fbshipit-source-id: 9c16f2a5ce41bc6aadf085e48449b19ede8423e4
2021-04-19 18:11:13 -07:00
Zhichao Cao
17002365c1 Replace Status with IOStatus for block fetcher IO function (#8130)
Summary:
To propagate the IOStatus from file reads to RocksDB read logic, some of the existing status needs to be replaced by IOStatus.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8130

Test Plan: make check

Reviewed By: anand1976

Differential Revision: D27440188

Pulled By: zhichao-cao

fbshipit-source-id: bbe7622c2106fe4e46871d60f7c26944e5030d78
2021-04-01 10:07:55 -07:00
yaphet
70e80c91b6 fix typo (#8118)
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/8118

Reviewed By: ajkr

Differential Revision: D27367488

Pulled By: zhichao-cao

fbshipit-source-id: 6ed598c74ab9232f2e56326b3a30476d473699d7
2021-03-29 10:32:10 -07:00
darionyaphet
0a5d23944d use the pointer directly (#8095)
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/8095

Reviewed By: riversand963

Differential Revision: D27318295

Pulled By: jay-zhuang

fbshipit-source-id: a014fbd28fdd7a26648da19a766dc00d2de9fdc8
2021-03-26 21:31:16 -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
Peter Dillinger
4b18c46d10 Refactor: add LineFileReader and Status::MustCheck (#8026)
Summary:
Removed confusing, awkward, and undocumented internal API
ReadOneLine and replaced with very simple LineFileReader.

In refactoring backupable_db.cc, this has the side benefit of
removing the arbitrary cap on the size of backup metadata files.

Also added Status::MustCheck to make it easy to mark a Status as
"must check." Using this, I can ensure that after
LineFileReader::ReadLine returns false the caller checks GetStatus().

Also removed some excessive conditional compilation in status.h

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8026

Test Plan: added unit test, and running tests with ASSERT_STATUS_CHECKED

Reviewed By: mrambacher

Differential Revision: D26831687

Pulled By: pdillinger

fbshipit-source-id: ef749c265a7a26bb13cd44f6f0f97db2955f6f0f
2021-03-09 20:12:38 -08:00
Akanksha Mahajan
cd79a00903 Make BlockBasedTable::kMaxAutoReadAheadSize configurable (#7951)
Summary:
RocksDB does auto-readahead for iterators on noticing more
than two reads for a table file. The readahead starts at 8KB and doubles on every
additional read upto BlockBasedTable::kMaxAutoReadAheadSize which is
256*1024.
This PR adds a new option BlockBasedTableOptions::max_auto_readahead_size which
replaces BlockBasedTable::kMaxAutoReadAheadSize and the new option can be
configured.
If max_auto_readahead_size is set 0 then no implicit auto prefetching will
be done. If max_auto_readahead_size provided is less than
8KB (which is initial readahead size used by rocksdb in case of
auto-readahead), readahead size will remain same as max_auto_readahead_size.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7951

Test Plan: Add new unit test case.

Reviewed By: anand1976

Differential Revision: D26568085

Pulled By: akankshamahajan15

fbshipit-source-id: b6543520fc74e97d859f2002328d4c5254d417af
2021-02-23 16:54:08 -08:00
Ziyue Yang
0c2d71edba Fix typo: replace readadhead with readahead (#7953)
Summary:
This PR replaces several "readadhead" typos with "readahead".

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7953

Reviewed By: ajkr

Differential Revision: D26518903

Pulled By: jay-zhuang

fbshipit-source-id: 6f7dece0e39ec4f71c4a936399bcb2e02574f42a
2021-02-18 14:31:20 -08:00
Zhichao Cao
d1c510baec Handoff checksum Implementation (#7523)
Summary:
in PR https://github.com/facebook/rocksdb/issues/7419 , we introduce the new Append and PositionedAppend APIs to WritableFile at File System, which enable RocksDB to pass the data verification information (e.g., checksum of the data) to the lower layer. In this PR, we use the new API in WritableFileWriter, such that the file created via WritableFileWrite can pass the checksum to the storage layer. To control which types file should apply the checksum handoff, we add checksum_handoff_file_types to DBOptions. User can use this option to control which file types (Currently supported file tyes: kLogFile, kTableFile, kDescriptorFile.) should use the new Append and PositionedAppend APIs to handoff the verification information.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7523

Test Plan: add new unit test, pass make check/ make asan_check

Reviewed By: pdillinger

Differential Revision: D24313271

Pulled By: zhichao-cao

fbshipit-source-id: aafd69091ae85c3318e3e17cbb96fe7338da11d0
2021-02-10 22:20:32 -08:00
mrambacher
4a09d632c4 Remove Legacy and Custom FileWrapper classes from header files (#7851)
Summary:
Removed the uses of the Legacy FileWrapper classes from the source code.  The wrappers were creating an additional layer of indirection/wrapping, as the Env already has a FileSystem.

Moved the Custom FileWrapper classes into the CustomEnv, as these classes are really for the private use the the CustomEnv class.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7851

Reviewed By: anand1976

Differential Revision: D26114816

Pulled By: mrambacher

fbshipit-source-id: db32840e58d969d3a0fa6c25aaf13d6dcdc74150
2021-01-28 22:10:32 -08:00
mrambacher
12f1137355 Add a SystemClock class to capture the time functions of an Env (#7858)
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
2021-01-25 22:09:11 -08:00
Akanksha Mahajan
1d226018af In IOTracing, add filename with each operation in trace file. (#7885)
Summary:
1. In IOTracing, add filename with each IOTrace record. Filename is stored in file object (Tracing Wrappers).
         2. Change the logic of figuring out which additional information (file_size,
            length, offset etc) needs to be store with each operation
            which is different for different operations.
            When new information will be added in future (depends on operation),
            this change would make the future additions simple.

Logic: In IOTraceRecord, io_op_data is added and its
         bitwise positions represent which additional information need
         to added in the record from enum IOTraceOp. Values in IOTraceOp represent bitwise positions.
         So if length and offset needs to be stored (IOTraceOp::kIOLen
         is 1 and IOTraceOp::kIOOffset is 2), position 1 and 2 (from rightmost bit) will be set
         and io_op_data will contain 110.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7885

Test Plan: Updated io_tracer_test and verified the trace file manually.

Reviewed By: anand1976

Differential Revision: D25982353

Pulled By: akankshamahajan15

fbshipit-source-id: ebfc5539cc0e231d7794a6b42b73f5403e360b22
2021-01-25 14:37:35 -08:00