Summary:
For performance purposes, the lower level routines were changed to use a SystemClock* instead of a std::shared_ptr<SystemClock>. The shared ptr has some performance degradation on certain hardware classes.
For most of the system, there is no risk of the pointer being deleted/invalid because the shared_ptr will be stored elsewhere. For example, the ImmutableDBOptions stores the Env which has a std::shared_ptr<SystemClock> in it. The SystemClock* within the ImmutableDBOptions is essentially a "short cut" to gain access to this constant resource.
There were a few classes (PeriodicWorkScheduler?) where the "short cut" property did not hold. In those cases, the shared pointer was preserved.
Using db_bench readrandom perf_level=3 on my EC2 box, this change performed as well or better than 6.17:
6.17: readrandom : 28.046 micros/op 854902 ops/sec; 61.3 MB/s (355999 of 355999 found)
6.18: readrandom : 32.615 micros/op 735306 ops/sec; 52.7 MB/s (290999 of 290999 found)
PR: readrandom : 27.500 micros/op 871909 ops/sec; 62.5 MB/s (367999 of 367999 found)
(Note that the times for 6.18 are prior to revert of the SystemClock).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8033
Reviewed By: pdillinger
Differential Revision: D27014563
Pulled By: mrambacher
fbshipit-source-id: ad0459eba03182e454391b5926bf5cdd45657b67
Summary:
Introduces and uses a SystemClock class to RocksDB. This class contains the time-related functions of an Env and these functions can be redirected from the Env to the SystemClock.
Many of the places that used an Env (Timer, PerfStepTimer, RepeatableThread, RateLimiter, WriteController) for time-related functions have been changed to use SystemClock instead. There are likely more places that can be changed, but this is a start to show what can/should be done. Over time it would be nice to migrate most (if not all) of the uses of the time functions from the Env to the SystemClock.
There are several Env classes that implement these functions. Most of these have not been converted yet to SystemClock implementations; that will come in a subsequent PR. It would be good to unify many of the Mock Timer implementations, so that they behave similarly and be tested similarly (some override Sleep, some use a MockSleep, etc).
Additionally, this change will allow new methods to be introduced to the SystemClock (like https://github.com/facebook/rocksdb/issues/7101 WaitFor) in a consistent manner across a smaller number of classes.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7858
Reviewed By: pdillinger
Differential Revision: D26006406
Pulled By: mrambacher
fbshipit-source-id: ed10a8abbdab7ff2e23d69d85bd25b3e7e899e90
Summary:
In the original stacked BlobDB implementation, which writes blobs to blob files
immediately and treats blob files as logs, it makes sense to flush the file after
writing each blob to protect against process crashes; however, in the integrated
implementation, which builds blob files in the background jobs, this unnecessarily
reduces performance. This patch fixes this by simply adding a `do_flush` flag to
`BlobLogWriter`, which is set to `true` by the stacked implementation and to `false`
by the new code. Note: the change itself is trivial but the tests needed some work;
since in the new implementation, blobs are now buffered, adding a blob to
`BlobFileBuilder` is no longer guaranteed to result in an actual I/O. Therefore, we can
no longer rely on `FaultInjectionTestEnv` when testing failure cases; instead, we
manipulate the return values of I/O methods directly using `SyncPoint`s.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7892
Test Plan: `make check`
Reviewed By: jay-zhuang
Differential Revision: D26022814
Pulled By: ltamasi
fbshipit-source-id: b3dce419f312137fa70d84cdd9b908fd5d60d8cd
Summary:
The patch adds a class called `BlobFileBuilder` that can be used to build
and cut blob files in background jobs (flushes/compactions). The class
enforces a value size threshold (`min_blob_size`; smaller blobs will be inlined
in the LSM tree itself), and supports specifying a blob file size limit (`blob_file_size`),
as well as compression (`blob_compression_type`) and checksums for blob files.
It also keeps track of the generated blob files and their associated `BlobFileAddition`
metadata, which can be applied as part of the background job's `VersionEdit`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7306
Test Plan: `make check`
Reviewed By: riversand963
Differential Revision: D23298817
Pulled By: ltamasi
fbshipit-source-id: 38f35d81dab1ba81f15236240612ec173d7f21b5
Summary:
The patch makes sure that the functionality required for the new integrated
BlobDB implementation (most importantly, the classes related to reading and
writing blob files) is also built in LITE mode by removing the corresponding
`#ifndef`s.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7272
Test Plan: Ran `make check` in both regular and LITE mode.
Reviewed By: zhichao-cao
Differential Revision: D23173280
Pulled By: ltamasi
fbshipit-source-id: 1596bd1a76409a8a6d83d8f1dbfe08bfdea7ffe6
Summary:
BlobDB currently syncs each blob file periodically after writing a certain amount of
data (as specified by the configuration option `BlobDBOptions::bytes_per_sync`)
and all open blob files when the base DB's memtables are flushed. With the patch,
in addition to the above, blob files are also synced right before being closed, after
the footer has been written. This will be beneficial for the new integrated blob file
write path as well.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7160
Test Plan: `make check`
Reviewed By: riversand963
Differential Revision: D22672646
Pulled By: ltamasi
fbshipit-source-id: 62b34263543a7e74abcbb7adf011daa1e699998f
Summary:
Periodic syncing of blob files is performed by `WritableFileWriter`;
`bytes_per_sync_` and `next_sync_offset_` in `BlobLogWriter` are
actually unused (or more precisely, only used by methods that are
themselves unused). The patch removes all this dead code.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7125
Test Plan: `make check`
Reviewed By: riversand963
Differential Revision: D22531021
Pulled By: ltamasi
fbshipit-source-id: 6b293ad5a79d3e6bf15c5c68f7aedd7ce7a15f10
