Summary:
For dictionary compression, we need to collect some representative samples of the data to be compressed, which we use to either generate or train (when `CompressionOptions::zstd_max_train_bytes > 0`) a dictionary. Previously, the strategy was to buffer all the data blocks during flush, and up to the target file size during compaction. That strategy allowed us to randomly pick samples from as wide a range as possible that'd be guaranteed to land in a single output file.
However, some users try to make huge files in memory-constrained environments, where this strategy can cause OOM. This PR introduces an option, `CompressionOptions::max_dict_buffer_bytes`, that limits how much data blocks are buffered before we switch to unbuffered mode (which means creating the per-SST dictionary, writing out the buffered data, and compressing/writing new blocks as soon as they are built). It is not strict as we currently buffer more than just data blocks -- also keys are buffered. But it does make a step towards giving users predictable memory usage.
Related changes include:
- Changed sampling for dictionary compression to select unique data blocks when there is limited availability of data blocks
- Made use of `BlockBuilder::SwapAndReset()` to save an allocation+memcpy when buffering data blocks for building a dictionary
- Changed `ParseBoolean()` to accept an input containing characters after the boolean. This is necessary since, with this PR, a value for `CompressionOptions::enabled` is no longer necessarily the final component in the `CompressionOptions` string.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7970
Test Plan:
- updated `CompressionOptions` unit tests to verify limit is respected (to the extent expected in the current implementation) in various scenarios of flush/compaction to bottommost/non-bottommost level
- looked at jemalloc heap profiles right before and after switching to unbuffered mode during flush/compaction. Verified memory usage in buffering is proportional to the limit set.
Reviewed By: pdillinger
Differential Revision: D26467994
Pulled By: ajkr
fbshipit-source-id: 3da4ef9fba59974e4ef40e40c01611002c861465
Summary:
Hi, I noticed a bug in rocksdb C API, where a function is not exported and created a fix.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7967
Reviewed By: jay-zhuang
Differential Revision: D26505722
Pulled By: ajkr
fbshipit-source-id: 05d676dbd59ec87fe32322cda9e39e405b07178d
Summary:
This PR creates `rocksdb_open_column_families_with_ttl` which allows C API users to open a DBWithTLL with column families.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7314
Reviewed By: cheng-chang
Differential Revision: D23430287
Pulled By: ajkr
fbshipit-source-id: 307aa21d170d1402653263a91f6f832ef76afba0
Summary:
Added setting of zstd_max_train_bytes compression option parameter to c interop.
rocksdb_options_set_bottommost_compression_options was using bool parameter and thus not exported, updated it to unsigned char and added to c.h as well.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6796
Reviewed By: cheng-chang
Differential Revision: D21611471
Pulled By: ajkr
fbshipit-source-id: caaaf153de934837ad9af283c7f8c025ff0b0cf5
Summary:
Adding a C API function to set `row_cache` on `rocksdb_options_t` as this functionality is missing.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6442
Differential Revision: D20036813
Pulled By: riversand963
fbshipit-source-id: c1fa95ea343345fbc1e57961d0d048e0e79be373
Summary:
When paranoid_checks is on, DBImpl::CheckConsistency() iterates over all sst files and calls Env::GetFileSize() for each of them. As far as I could understand, this is pretty arbitrary and doesn't affect correctness - if filesystem doesn't corrupt fsynced files, the file sizes will always match; if it does, it may as well corrupt contents as well as sizes, and rocksdb doesn't check contents on open.
If there are thousands of sst files, getting all their sizes takes a while. If, on top of that, Env is overridden to use some remote storage instead of local filesystem, it can be *really* slow and overload the remote storage service. This PR adds an option to not do GetFileSize(); instead it does GetChildren() for parent directory to check that all the expected sst files are at least present, but doesn't check their sizes.
We can't just disable paranoid_checks instead because paranoid_checks do a few other important things: make the DB read-only on write errors, print error messages on read errors, etc.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6353
Test Plan: ran the added sanity check unit test. Will try it out in a LogDevice test cluster where the GetFileSize() calls are causing a lot of trouble.
Differential Revision: D19656425
Pulled By: al13n321
fbshipit-source-id: c2c421b367633033760d1f56747bad206d1fbf82
Summary:
This PR adds a `rocksdb_options_set_atomic_flush` function to the C API.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6307
Differential Revision: D19451313
Pulled By: ltamasi
fbshipit-source-id: 750495642ef55b1ea7e13477f85c38cd6574849c
Summary:
This makes it easier to call the functions from Rust as otherwise they require mutable types.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6283
Differential Revision: D19349991
Pulled By: wqfish
fbshipit-source-id: e8da7a75efe8cd97757baef8ca844a054f2519b4
Summary:
Fix an error message when CURRENT is not found.
Test plan (dev server)
```
make check
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6264
Differential Revision: D19300699
Pulled By: riversand963
fbshipit-source-id: 303fa206386a125960ecca1dbdeff07422690caf
Summary:
It seems that the C-API doesn't expose the range delete functionality at the moment, so add the API.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6259
Differential Revision: D19290320
Pulled By: pdillinger
fbshipit-source-id: 3f403a4c3446d2042d55f1ece7cdc9c040f40c27
Summary:
Adds two missing functions to the C-API:
- `rocksdb_block_based_options_set_data_block_index_type`
- `rocksdb_block_based_options_set_data_block_hash_ratio`
This enables users in other languages to enjoy the new(-ish) feature.
The changes here are partially overlapping with [another PR](https://github.com/facebook/rocksdb/pull/5630) but are more focused on the DataBlock indexing options.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6101
Differential Revision: D18765639
fbshipit-source-id: 4a8947e71b179f26fa1eb83c267dd47ee64ac3b3
Summary:
MyRocks currently sets `max_write_buffer_number_to_maintain` in order to maintain enough history for transaction conflict checking. The effectiveness of this approach depends on the size of memtables. When memtables are small, it may not keep enough history; when memtables are large, this may consume too much memory.
We are proposing a new way to configure memtable list history: by limiting the memory usage of immutable memtables. The new option is `max_write_buffer_size_to_maintain` and it will take precedence over the old `max_write_buffer_number_to_maintain` if they are both set to non-zero values. The new option accounts for the total memory usage of flushed immutable memtables and mutable memtable. When the total usage exceeds the limit, RocksDB may start dropping immutable memtables (which is also called trimming history), starting from the oldest one.
The semantics of the old option actually works both as an upper bound and lower bound. History trimming will start if number of immutable memtables exceeds the limit, but it will never go below (limit-1) due to history trimming.
In order the mimic the behavior with the new option, history trimming will stop if dropping the next immutable memtable causes the total memory usage go below the size limit. For example, assuming the size limit is set to 64MB, and there are 3 immutable memtables with sizes of 20, 30, 30. Although the total memory usage is 80MB > 64MB, dropping the oldest memtable will reduce the memory usage to 60MB < 64MB, so in this case no memtable will be dropped.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5022
Differential Revision: D14394062
Pulled By: miasantreble
fbshipit-source-id: 60457a509c6af89d0993f988c9b5c2aa9e45f5c5
Summary:
Add C binding for secondary instance as well as unit test.
Test plan (on devserver)
```
$make clean && COMPILE_WITH_ASAN=1 make -j20 all
$./c_test
$make check
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5505
Differential Revision: D16000043
Pulled By: riversand963
fbshipit-source-id: 3361ef6bfdf4ce12438cee7290a0ac203b5250bd
Summary:
Performing unordered writes in rocksdb when unordered_write option is set to true. When enabled the writes to memtable are done without joining any write thread. This offers much higher write throughput since the upcoming writes would not have to wait for the slowest memtable write to finish. The tradeoff is that the writes visible to a snapshot might change over time. If the application cannot tolerate that, it should implement its own mechanisms to work around that. Using TransactionDB with WRITE_PREPARED write policy is one way to achieve that. Doing so increases the max throughput by 2.2x without however compromising the snapshot guarantees.
The patch is prepared based on an original by siying
Existing unit tests are extended to include unordered_write option.
Benchmark Results:
```
TEST_TMPDIR=/dev/shm/ ./db_bench_unordered --benchmarks=fillrandom --threads=32 --num=10000000 -max_write_buffer_number=16 --max_background_jobs=64 --batch_size=8 --writes=3000000 -level0_file_num_compaction_trigger=99999 --level0_slowdown_writes_trigger=99999 --level0_stop_writes_trigger=99999 -enable_pipelined_write=false -disable_auto_compactions --unordered_write=1
```
With WAL
- Vanilla RocksDB: 78.6 MB/s
- WRITER_PREPARED with unordered_write: 177.8 MB/s (2.2x)
- unordered_write: 368.9 MB/s (4.7x with relaxed snapshot guarantees)
Without WAL
- Vanilla RocksDB: 111.3 MB/s
- WRITER_PREPARED with unordered_write: 259.3 MB/s MB/s (2.3x)
- unordered_write: 645.6 MB/s (5.8x with relaxed snapshot guarantees)
- WRITER_PREPARED with unordered_write disable concurrency control: 185.3 MB/s MB/s (2.35x)
Limitations:
- The feature is not yet extended to `max_successive_merges` > 0. The feature is also incompatible with `enable_pipelined_write` = true as well as with `allow_concurrent_memtable_write` = false.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5218
Differential Revision: D15219029
Pulled By: maysamyabandeh
fbshipit-source-id: 38f2abc4af8780148c6128acdba2b3227bc81759
Summary:
There were no C bindings for lowering thread pool priority. This adds those.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5285
Differential Revision: D15290050
Pulled By: siying
fbshipit-source-id: b2ed94d0c39d27434ace2204829a242b53d0d67a
Summary:
Part of compaction cpu goes to processing snapshot list, the larger the list the bigger the overhead. Although the lifetime of most of the snapshots is much shorter than the lifetime of compactions, the compaction conservatively operates on the list of snapshots that it initially obtained. This patch allows the snapshot list to be updated via a callback if the compaction is taking long. This should let the compaction to continue more efficiently with much smaller snapshot list.
For simplicity, to avoid the feature is disabled in two cases: i) When more than one sub-compaction are sharing the same snapshot list, ii) when Range Delete is used in which the range delete aggregator has its own copy of snapshot list.
This fixes the reverted https://github.com/facebook/rocksdb/pull/5099 issue with range deletes.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5278
Differential Revision: D15203291
Pulled By: maysamyabandeh
fbshipit-source-id: fa645611e606aa222c7ce53176dc5bb6f259c258
Summary:
Our daily stress tests are failing after this feature. Reverting temporarily until we figure the reason for test failures.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5269
Differential Revision: D15151285
Pulled By: maysamyabandeh
fbshipit-source-id: e4002b99690a97df30d4b4b58bf0f61e9591bc6e
Summary:
Part of compaction cpu goes to processing snapshot list, the larger the list the bigger the overhead. Although the lifetime of most of the snapshots is much shorter than the lifetime of compactions, the compaction conservatively operates on the list of snapshots that it initially obtained. This patch allows the snapshot list to be updated via a callback if the compaction is taking long. This should let the compaction to continue more efficiently with much smaller snapshot list.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5099
Differential Revision: D15086710
Pulled By: maysamyabandeh
fbshipit-source-id: 7649f56c3b6b2fb334962048150142a3bf9c1a12
Summary:
Current implementation of `current_over_upper_bound_` fails to take into consideration that keys might be invalid in either base iterator or delta iterator. Calling key() in such scenario will lead to assertion failure and runtime errors.
This PR addresses the bug by adding check for valid keys before calling `IsOverUpperBound()`, also added test coverage for iterate_upper_bound usage in BaseDeltaIterator
Also recommit https://github.com/facebook/rocksdb/pull/4656 (It was reverted earlier due to bugs)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4702
Differential Revision: D13146643
Pulled By: miasantreble
fbshipit-source-id: 6d136929da12d0f2e2a5cea474a8038ec5cdf1d0
Summary:
Currently transaction iterator does not apply `ReadOptions.iterate_upper_bound` when iterating. This PR attempts to fix the problem by having `BaseDeltaIterator` enforcing the upper bound check when iterator state is changed.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4656
Differential Revision: D13039257
Pulled By: miasantreble
fbshipit-source-id: 909eb9f6b4597a4d80418fb139f32ec82c6ec1d1
Summary:
he ratio of num_deletions to num_entries of a level can be useful to determine if a manual compaction needs to be triggered on a level.
Also refer #3980
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4623
Differential Revision: D13045744
Pulled By: sagar0
fbshipit-source-id: 71f3c8e363a8ffd194ec3bb0ed0b69612231f0b3
Ed rodriguez