Commit Graph

34 Commits

Author SHA1 Message Date
Mike Kolupaev
120bc4715b Add DBOptions. avoid_unnecessary_blocking_io to defer file deletions (#5043)
Summary:
Just like ReadOptions::background_purge_on_iterator_cleanup but for ColumnFamilyHandle instead of Iterator.

In our use case we sometimes call ColumnFamilyHandle's destructor from low-latency threads, and sometimes it blocks the thread for a few seconds deleting the files. To avoid that, we can either offload ColumnFamilyHandle's destruction to a background thread on our side, or add this option on rocksdb side. This PR does the latter, to be consistent with how we solve exactly the same problem for iterators using background_purge_on_iterator_cleanup option.

(EDIT: It's avoid_unnecessary_blocking_io now, and affects both CF drops and iterator destructors.)
I'm not quite comfortable with having two separate options (background_purge_on_iterator_cleanup and background_purge_on_cf_cleanup) for such a rarely used thing. Maybe we should merge them? Rename background_purge_on_cf_cleanup to something like delete_files_on_background_threads_only or avoid_blocking_io_in_unexpected_places, and make iterators use it instead of the one in ReadOptions? I can do that here if you guys think it's better.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5043

Differential Revision: D14339233

Pulled By: al13n321

fbshipit-source-id: ccf7efa11c85c9a5b91d969bb55627d0fb01e7b8
2019-04-01 17:10:40 -07:00
Shobhit Dayal
b45b1cde3e Feature for sampling and reporting compressibility (#4842)
Summary:
This is a feature to sample data-block compressibility and and report them as stats. 1 in N (tunable) blocks is sampled for compressibility using two algorithms:
1. lz4 or snappy for fast compression
2. zstd or zlib for slow but higher compression.

The stats are reported to the caller as raw-bytes and compressed-bytes. The block continues to be compressed for storage using the specified CompressionType.

The db_bench_tool how has a command line option for specifying the sampling rate. It's default value is 0 (no sampling). To test the overhead for a certain value, users can compare the performance of db_bench_tool, varying the sampling rate. It is unlikely to have a noticeable impact for high values like 20.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4842

Differential Revision: D13629011

Pulled By: shobhitdayal

fbshipit-source-id: 14ca668bcab6499b2a1734edf848eb62a4f4fafa
2019-03-18 12:15:34 -07:00
Zhongyi Xie
c4f5d0aa15 add GetStatsHistory to retrieve stats snapshots (#4748)
Summary:
This PR adds public `GetStatsHistory` API to retrieve stats history in the form of an std map. The key of the map is the timestamp in microseconds when the stats snapshot is taken, the value is another std map from stats name to stats value (stored in std string). Two DBOptions are introduced: `stats_persist_period_sec` (default 10 minutes) controls the intervals between two snapshots are taken; `max_stats_history_count` (default 10) controls the max number of history snapshots to keep in memory. RocksDB will stop collecting stats snapshots if `stats_persist_period_sec` is set to 0.

(This PR is the in-memory part of https://github.com/facebook/rocksdb/pull/4535)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4748

Differential Revision: D13961471

Pulled By: miasantreble

fbshipit-source-id: ac836d401ecb84ea92216bf9966f969dedf4ad04
2019-02-20 15:52:54 -08:00
Zhongyi Xie
ed995c6a69 add whole key bloom filter support in memtables (#4985)
Summary:
MyRocks calls `GetForUpdate` on `INSERT`, for unique key check, and in almost all cases GetForUpdate returns empty result. For such cases, whole key bloom filter is helpful.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4985

Differential Revision: D14118257

Pulled By: miasantreble

fbshipit-source-id: d35cb7109c62fd5ad541a26968e3a3e16d3e85ea
2019-02-19 12:15:39 -08:00
Aubin Sanyal
3231a2e581 Deprecate ttl option from CompactionOptionsFIFO (#4965)
Summary:
We introduced ttl option in CompactionOptionsFIFO when ttl-based file
deletion (compaction) was supported only as part of FIFO Compaction. But
with the extension of ttl semantics even to Level compaction,
CompactionOptionsFIFO.ttl can now be deprecated. Instead we will start
using ColumnFamilyOptions.ttl for FIFO compaction as well.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4965

Differential Revision: D14072960

Pulled By: sagar0

fbshipit-source-id: c98cc2ae695a28136295787cd88d36a220fc219e
2019-02-15 09:51:41 -08:00
Burton Li
a8b9891f95 Concurrent task limiter for compaction thread control (#4332)
Summary:
The PR is targeting to resolve the issue of:
https://github.com/facebook/rocksdb/issues/3972#issue-330771918

We have a rocksdb created with leveled-compaction with multiple column families (CFs), some of CFs are using HDD to store big and less frequently accessed data and others are using SSD.
When there are continuously write traffics going on to all CFs, the compaction thread pool is mostly occupied by those slow HDD compactions, which blocks fully utilize SSD bandwidth.
Since atomic write and transaction is needed across CFs, so splitting it to multiple rocksdb instance is not an option for us.

With the compaction thread control, we got 30%+ HDD write throughput gain, and also a lot smooth SSD write since less write stall happening.

ConcurrentTaskLimiter can be shared with multi-CFs across rocksdb instances, so the feature does not only work for multi-CFs scenarios, but also for multi-rocksdbs scenarios, who need disk IO resource control per tenant.

The usage is straight forward:
e.g.:

//
// Enable compaction thread limiter thru ColumnFamilyOptions
//
std::shared_ptr<ConcurrentTaskLimiter> ctl(NewConcurrentTaskLimiter("foo_limiter", 4));
Options options;
ColumnFamilyOptions cf_opt(options);
cf_opt.compaction_thread_limiter = ctl;
...

//
// Compaction thread limiter can be tuned or disabled on-the-fly
//
ctl->SetMaxOutstandingTask(12); // enlarge to 12 tasks
...
ctl->ResetMaxOutstandingTask(); // disable (bypass) thread limiter
ctl->SetMaxOutstandingTask(-1); // Same as above
...
ctl->SetMaxOutstandingTask(0);  // full throttle (0 task)

//
// Sharing compaction thread limiter among CFs (to resolve multiple storage perf issue)
//
std::shared_ptr<ConcurrentTaskLimiter> ctl_ssd(NewConcurrentTaskLimiter("ssd_limiter", 8));
std::shared_ptr<ConcurrentTaskLimiter> ctl_hdd(NewConcurrentTaskLimiter("hdd_limiter", 4));
Options options;
ColumnFamilyOptions cf_opt_ssd1(options);
ColumnFamilyOptions cf_opt_ssd2(options);
ColumnFamilyOptions cf_opt_hdd1(options);
ColumnFamilyOptions cf_opt_hdd2(options);
ColumnFamilyOptions cf_opt_hdd3(options);

// SSD CFs
cf_opt_ssd1.compaction_thread_limiter = ctl_ssd;
cf_opt_ssd2.compaction_thread_limiter = ctl_ssd;

// HDD CFs
cf_opt_hdd1.compaction_thread_limiter = ctl_hdd;
cf_opt_hdd2.compaction_thread_limiter = ctl_hdd;
cf_opt_hdd3.compaction_thread_limiter = ctl_hdd;

...

//
// The limiter is disabled by default (or set to nullptr explicitly)
//
Options options;
ColumnFamilyOptions cf_opt(options);
cf_opt.compaction_thread_limiter = nullptr;
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4332

Differential Revision: D13226590

Pulled By: siying

fbshipit-source-id: 14307aec55b8bd59c8223d04aa6db3c03d1b0c1d
2018-12-13 13:18:28 -08:00
Yi Wu
05d9d82181 Revert "Move MemoryAllocator option from Cache to BlockBasedTableOpti… (#4697)
Summary:
…ons (#4676)"

This reverts commit b32d087dbb.

`MemoryAllocator` needs to be with `Cache`, since cache entry can
outlive DB and block based table. The cache needs to hold reference to
memory allocator when deleting cache entry.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4697

Differential Revision: D13133490

Pulled By: yiwu-arbug

fbshipit-source-id: 8ef7e8a51263bfd929f892fd062665ff4ce9ce5a
2018-11-21 11:29:57 -08:00
Yi Wu
b32d087dbb Move MemoryAllocator option from Cache to BlockBasedTableOptions (#4676)
Summary:
Per offline discussion with siying, `MemoryAllocator` and `Cache` should be decouple. The idea is that memory allocator handles memory allocation, while cache handle cache policy.

It is normal that external cache libraries pack couple the two components for better optimization. If we want to integrate with such library in the future, we can make a wrapper of the library implementing both `Cache` and `MemoryAllocator` interface.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4676

Differential Revision: D13047662

Pulled By: yiwu-arbug

fbshipit-source-id: cd42e246d80ab600b4de47d073f7d2db308ce6dd
2018-11-13 13:48:38 -08:00
Yanqin Jin
5b4c709fad Enable atomic flush (#4023)
Summary:
Adds a DB option `atomic_flush` to control whether to enable this feature. This PR is a subset of [PR 3752](https://github.com/facebook/rocksdb/pull/3752).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4023

Differential Revision: D8518381

Pulled By: riversand963

fbshipit-source-id: 1e3bb33e99bb102876a31b378d93b0138ff6634f
2018-10-26 15:08:43 -07:00
Fenggang Wu
19ec44fd39 Improve point-lookup performance using a data block hash index (#4174)
Summary:
Add hash index support to data blocks, which helps to reduce the CPU utilization of point-lookup operations. This feature is backward compatible with the data block created without the hash index. It is disabled by default unless `BlockBasedTableOptions::data_block_index_type` is set to `data_block_index_type = kDataBlockBinaryAndHash.`

The DB size would be bigger with the hash index option as a hash table is added at the end of each data block. If the hash utilization ratio is 1:1, the space overhead is one byte per key. The hash table utilization ratio is adjustable using `BlockBasedTableOptions::data_block_hash_table_util_ratio`. A lower utilization ratio will improve more on the point-lookup efficiency, but take more space too.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4174

Differential Revision: D8965914

Pulled By: fgwu

fbshipit-source-id: 1c6bae5d1fc39c80282d8890a72e9e67bc247198
2018-08-15 14:30:03 -07:00
Fenggang Wu
a11df583ec Add DataBlockIndexType option in BlockBasedTableOptions (#4150)
Summary:
Added DataBlockIndexType option in BlockBasedTableOptions.
```
enum DataBlockIndexType : char {
    kDataBlockBinarySearch = 0, // traditional block type
    kDataBlockHashIndex = 1, // additional hash index appended to the end.
};
```
The default type is the traditional binary seek option: `kDataBlockBinarySearch`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4150

Differential Revision: D8895958

Pulled By: fgwu

fbshipit-source-id: 480adef48104cf11d30db3bad9a73f98b4a80c10
2018-07-27 15:42:27 -07:00
Zhichao Cao
1f6efabe23 Add bottommost_compression_opts to for bottommost_compression (#3985)
Summary:
…ression

 For `CompressionType` we have options `compression` and `bottommost_compression`. Thus, to make the compression options consitent with the compression type when bottommost_compression is enabled, we add the bottommost_compression_opts
Closes https://github.com/facebook/rocksdb/pull/3985

Reviewed By: riversand963

Differential Revision: D8385911

Pulled By: zhichao-cao

fbshipit-source-id: 07bc533dd61bcf1cef5927d8d62901c13d38d5fc
2018-06-27 17:42:38 -07:00
Maysam Yabandeh
80ade9ad83 Pin top-level index on partitioned index/filter blocks (#4037)
Summary:
Top-level index in partitioned index/filter blocks are small and could be pinned in memory. So far we use that by cache_index_and_filter_blocks to false. This however make it difficult to keep account of the total memory usage. This patch introduces pin_top_level_index_and_filter which in combination with cache_index_and_filter_blocks=true keeps the top-level index in cache and yet pinned them to avoid cache misses and also cache lookup overhead.
Closes https://github.com/facebook/rocksdb/pull/4037

Differential Revision: D8596218

Pulled By: maysamyabandeh

fbshipit-source-id: 3a5f7f9ca6b4b525b03ff6bd82354881ae974ad2
2018-06-22 15:27:46 -07:00
Phani Shekhar Mantripragada
446b32cfc3 Support for Column family specific paths.
Summary:
In this change, an option to set different paths for different column families is added.
This option is set via cf_paths setting of ColumnFamilyOptions. This option will work in a similar fashion to db_paths setting. Cf_paths is a vector of Dbpath values which contains a pair of the absolute path and target size. Multiple levels in a Column family can go to different paths if cf_paths has more than one path.
To maintain backward compatibility, if cf_paths is not specified for a column family, db_paths setting will be used. Note that, if db_paths setting is also not specified, RocksDB already has code to use db_name as the only path.

Changes :
1) A new member "cf_paths" is added to ImmutableCfOptions. This is set, based on cf_paths setting of ColumnFamilyOptions and db_paths setting of ImmutableDbOptions.  This member is used to identify the path information whenever files are accessed.
2) Validation checks are added for cf_paths setting based on existing checks for db_paths setting.
3) DestroyDB, PurgeObsoleteFiles etc. are edited to support multiple cf_paths.
4) Unit tests are added appropriately.
Closes https://github.com/facebook/rocksdb/pull/3102

Differential Revision: D6951697

Pulled By: ajkr

fbshipit-source-id: 60d2262862b0a8fd6605b09ccb0da32bb331787d
2018-04-05 19:58:20 -07:00
Sagar Vemuri
04c11b867d Level Compaction with TTL
Summary:
Level Compaction with TTL.

As of today, a file could exist in the LSM tree without going through the compaction process for a really long time if there are no updates to the data in the file's key range. For example, in certain use cases, the keys are not actually "deleted"; instead they are just set to empty values. There might not be any more writes to this "deleted" key range, and if so, such data could remain in the LSM for a really long time resulting in wasted space.

Introducing a TTL could solve this problem. Files (and, in turn, data) older than TTL will be scheduled for compaction when there is no other background work. This will make the data go through the regular compaction process and get rid of old unwanted data.
This also has the (good) side-effect of all the data in the non-bottommost level being newer than ttl, and all data in the bottommost level older than ttl. It could lead to more writes while reducing space.

This functionality can be controlled by the newly introduced column family option -- ttl.

TODO for later:
- Make ttl mutable
- Extend TTL to Universal compaction as well? (TTL is already supported in FIFO)
- Maybe deprecate CompactionOptionsFIFO.ttl in favor of this new ttl option.
Closes https://github.com/facebook/rocksdb/pull/3591

Differential Revision: D7275442

Pulled By: sagar0

fbshipit-source-id: dcba484717341200d419b0953dafcdf9eb2f0267
2018-04-02 22:14:28 -07:00
Anand Ananthabhotla
f9f4d40f93 Align SST file data blocks to avoid spanning multiple pages
Summary:
Provide a block_align option in BlockBasedTableOptions to allow
alignment of SST file data blocks. This will avoid higher
IOPS/throughput load due to < 4KB data blocks spanning 2 4KB pages.
When this option is set to true, the block alignment is set to lower of
block size and 4KB.
Closes https://github.com/facebook/rocksdb/pull/3502

Differential Revision: D7400897

Pulled By: anand1976

fbshipit-source-id: 04cc3bd144e88e3431a4f97604e63ad7a0f06d44
2018-03-26 20:26:10 -07:00
Anand Ananthabhotla
199405192d Add a BlockBasedTableOption to turn off index block compression.
Summary:
Add a new bool option index_uncompressed in BlockBasedTableOptions.
Closes https://github.com/facebook/rocksdb/pull/3303

Differential Revision: D6686161

Pulled By: anand1976

fbshipit-source-id: 748b46993d48a01e5f89b6bd3e41f06a59ec6054
2018-01-10 15:11:59 -08:00
Andrew Kryczka
63f1c0a57d fix gflags namespace
Summary:
I started adding gflags support for cmake on linux and got frustrated that I'd need to duplicate the build_detect_platform logic, which determines namespace based on attempting compilation. We can do it differently -- use the GFLAGS_NAMESPACE macro if available, and if not, that indicates it's an old gflags version without configurable namespace so we can simply hardcode "google".
Closes https://github.com/facebook/rocksdb/pull/3212

Differential Revision: D6456973

Pulled By: ajkr

fbshipit-source-id: 3e6d5bde3ca00d4496a120a7caf4687399f5d656
2017-12-01 10:42:05 -08:00
Maysam Yabandeh
0213990b3a Move static variables out of the header file
Summary:
Static variables in header files will be instantiated in every file that includes the header file. This patch moves some of them from options_helper.h to its .cc files. It also moves the static variable out of the offset_of since the template function could also lead to multiple instantiation perhaps due to inlining.

Fixes https://github.com/facebook/rocksdb/issues/3176
Closes https://github.com/facebook/rocksdb/pull/3178

Differential Revision: D6363794

Pulled By: maysamyabandeh

fbshipit-source-id: d0a07f061b4d992ab4e0de2706e622131d258fdd
2017-11-17 17:12:27 -08:00
Maysam Yabandeh
857adf388f WritePrepared Txn: Refactor conf params
Summary:
Summary of changes:
- Move seq_per_batch out of Options
- Rename concurrent_prepare to two_write_queues
- Add allocate_seq_only_for_data_
Closes https://github.com/facebook/rocksdb/pull/3136

Differential Revision: D6304458

Pulled By: maysamyabandeh

fbshipit-source-id: 08e685bfa82bbc41b5b1c5eb7040a8ca6e05e58c
2017-11-10 17:28:12 -08:00
Mikhail Antonov
7fe3b32896 Added support for differential snapshots
Summary:
The motivation for this PR is to add to RocksDB support for differential (incremental) snapshots, as snapshot of the DB changes between two points in time (one can think of it as diff between to sequence numbers, or the diff D which can be thought of as an SST file or just set of KVs that can be applied to sequence number S1 to get the database to the state at sequence number S2).

This feature would be useful for various distributed storages layers built on top of RocksDB, as it should help reduce resources (time and network bandwidth) needed to recover and rebuilt DB instances as replicas in the context of distributed storages.

From the API standpoint that would like client app requesting iterator between (start seqnum) and current DB state, and reading the "diff".

This is a very draft PR for initial review in the discussion on the approach, i'm going to rework some parts and keep updating the PR.

For now, what's done here according to initial discussions:

Preserving deletes:
 - We want to be able to optionally preserve recent deletes for some defined period of time, so that if a delete came in recently and might need to be included in the next incremental snapshot it would't get dropped by a compaction. This is done by adding new param to Options (preserve deletes flag) and new variable to DB Impl where we keep track of the sequence number after which we don't want to drop tombstones, even if they are otherwise eligible for deletion.
 - I also added a new API call for clients to be able to advance this cutoff seqnum after which we drop deletes; i assume it's more flexible to let clients control this, since otherwise we'd need to keep some kind of timestamp < -- > seqnum mapping inside the DB, which sounds messy and painful to support. Clients could make use of it by periodically calling GetLatestSequenceNumber(), noting the timestamp, doing some calculation and figuring out by how much we need to advance the cutoff seqnum.
 - Compaction codepath in compaction_iterator.cc has been modified to avoid dropping tombstones with seqnum > cutoff seqnum.

Iterator changes:
 - couple params added to ReadOptions, to optionally allow client to request internal keys instead of user keys (so that client can get the latest value of a key, be it delete marker or a put), as well as min timestamp and min seqnum.

TableCache changes:
 - I modified table_cache code to be able to quickly exclude SST files from iterators heep if creation_time on the file is less then iter_start_ts as passed in ReadOptions. That would help a lot in some DB settings (like reading very recent data only or using FIFO compactions), but not so much for universal compaction with more or less long iterator time span.

What's left:

 - Still looking at how to best plug that inside DBIter codepath. So far it seems that FindNextUserKeyInternal only parses values as UserKeys, and iter->key() call generally returns user key. Can we add new API to DBIter as internal_key(), and modify this internal method to optionally set saved_key_ to point to the full internal key? I don't need to store actual seqnum there, but I do need to store type.
Closes https://github.com/facebook/rocksdb/pull/2999

Differential Revision: D6175602

Pulled By: mikhail-antonov

fbshipit-source-id: c779a6696ee2d574d86c69cec866a3ae095aa900
2017-11-01 18:56:43 -07:00
Maysam Yabandeh
17731a43a6 WritePrepared Txn: Optimize for recoverable state
Summary:
GetCommitTimeWriteBatch is currently used to store some state as part of commit in 2PC. In MyRocks it is specifically used to store some data that would be needed only during recovery. So it is not need to be stored in memtable right after each commit.
This patch enables an optimization to write the GetCommitTimeWriteBatch only to the WAL. The batch will be written to memtable during recovery when the WAL is replayed. To cover the case when WAL is deleted after memtable flush, the batch is also buffered and written to memtable right before each memtable flush.
Closes https://github.com/facebook/rocksdb/pull/3071

Differential Revision: D6148023

Pulled By: maysamyabandeh

fbshipit-source-id: 2d09bae5565abe2017c0327421010d5c0d55eaa7
2017-11-01 17:26:46 -07:00
Sagar Vemuri
f0804db7f7 Make FIFO compaction options dynamically configurable
Summary:
ColumnFamilyOptions::compaction_options_fifo and all its sub-fields can be set dynamically now.

Some of the ways in which the fifo compaction options can be set are:
- `SetOptions({{"compaction_options_fifo", "{max_table_files_size=1024}"}})`
- `SetOptions({{"compaction_options_fifo", "{ttl=600;}"}})`
- `SetOptions({{"compaction_options_fifo", "{max_table_files_size=1024;ttl=600;}"}})`
- `SetOptions({{"compaction_options_fifo", "{max_table_files_size=51;ttl=49;allow_compaction=true;}"}})`

Most of the code has been made generic enough so that it could be reused later to make universal options (and other such nested defined-types) dynamic with very few lines of parsing/serializing code changes.
Introduced a few new functions like `ParseStruct`, `SerializeStruct` and `GetStringFromStruct`.
The duplicate code in `GetStringFromDBOptions` and `GetStringFromColumnFamilyOptions` has been moved into `GetStringFromStruct`. So they become just simple wrappers now.
Closes https://github.com/facebook/rocksdb/pull/3006

Differential Revision: D6058619

Pulled By: sagar0

fbshipit-source-id: 1e8f78b3374ca5249bb4f3be8a6d3bb4cbc52f92
2017-10-19 15:26:36 -07:00
Maysam Yabandeh
60beefd6e0 WritePrepared Txn: Advance seq one per batch
Summary:
By default the seq number in DB is increased once per written key. WritePrepared txns requires the seq to be increased once per the entire batch so that the seq would be used as the prepare timestamp by which the transaction is identified. Also we need to increase seq for the commit marker since it would give a unique id to the commit timestamp of transactions.

Two unit tests are added to verify our understanding of how the seq should be increased. The recovery path requires much more work and is left to another patch.
Closes https://github.com/facebook/rocksdb/pull/2885

Differential Revision: D5837843

Pulled By: maysamyabandeh

fbshipit-source-id: a08960b93d727e1cf438c254d0c2636fb133cc1c
2017-09-18 14:45:08 -07:00
Andrew Kryczka
9d115d3689 regression test for missing init options
Summary:
test the `DBOptions(const Options&)` and `ColumnFamilyOptions(const Options&)` constructors. Actually this'll work better once we refactor `RandomInitDBOptions` / `RandomInitCFOptions` to use the authoritative sources of struct members: `db_options_type_info` / `cf_options_type_info` (internal task T21804189 for this).
Closes https://github.com/facebook/rocksdb/pull/2873

Differential Revision: D5817141

Pulled By: ajkr

fbshipit-source-id: 8567c20feced9d1751fdf1f4383e2af30f7e3591
2017-09-13 11:56:35 -07:00
Siying Dong
3c327ac2d0 Change RocksDB License
Summary: Closes https://github.com/facebook/rocksdb/pull/2589

Differential Revision: D5431502

Pulled By: siying

fbshipit-source-id: 8ebf8c87883daa9daa54b2303d11ce01ab1f6f75
2017-07-15 16:11:23 -07:00
Maysam Yabandeh
499ebb3ab5 Optimize for serial commits in 2PC
Summary:
Throughput: 46k tps in our sysbench settings (filling the details later)

The idea is to have the simplest change that gives us a reasonable boost
in 2PC throughput.

Major design changes:
1. The WAL file internal buffer is not flushed after each write. Instead
it is flushed before critical operations (WAL copy via fs) or when
FlushWAL is called by MySQL. Flushing the WAL buffer is also protected
via mutex_.
2. Use two sequence numbers: last seq, and last seq for write. Last seq
is the last visible sequence number for reads. Last seq for write is the
next sequence number that should be used to write to WAL/memtable. This
allows to have a memtable write be in parallel to WAL writes.
3. BatchGroup is not used for writes. This means that we can have
parallel writers which changes a major assumption in the code base. To
accommodate for that i) allow only 1 WriteImpl that intends to write to
memtable via mem_mutex_--which is fine since in 2PC almost all of the memtable writes
come via group commit phase which is serial anyway, ii) make all the
parts in the code base that assumed to be the only writer (via
EnterUnbatched) to also acquire mem_mutex_, iii) stat updates are
protected via a stat_mutex_.

Note: the first commit has the approach figured out but is not clean.
Submitting the PR anyway to get the early feedback on the approach. If
we are ok with the approach I will go ahead with this updates:
0) Rebase with Yi's pipelining changes
1) Currently batching is disabled by default to make sure that it will be
consistent with all unit tests. Will make this optional via a config.
2) A couple of unit tests are disabled. They need to be updated with the
serial commit of 2PC taken into account.
3) Replacing BatchGroup with mem_mutex_ got a bit ugly as it requires
releasing mutex_ beforehand (the same way EnterUnbatched does). This
needs to be cleaned up.
Closes https://github.com/facebook/rocksdb/pull/2345

Differential Revision: D5210732

Pulled By: maysamyabandeh

fbshipit-source-id: 78653bd95a35cd1e831e555e0e57bdfd695355a4
2017-06-24 14:11:29 -07:00
Andrew Kryczka
bb01c1880c Introduce max_background_jobs mutable option
Summary:
- `max_background_flushes` and `max_background_compactions` are still supported for backwards compatibility
- `base_background_compactions` is completely deprecated. Now we just throttle to one background compaction when there's no pressure.
- `max_background_jobs` is added to automatically partition the concurrent background jobs into flushes vs compactions. Currently it's very simple as we just allocate one-fourth of the jobs to flushes, and the remaining can be used for compactions.
- The test cases that set `base_background_compactions > 1` needed to be updated. I just grab the pressure token such that the desired number of compactions can be scheduled.
Closes https://github.com/facebook/rocksdb/pull/2205

Differential Revision: D4937461

Pulled By: ajkr

fbshipit-source-id: df52cbbd497e13bbc9a60560a5ac2a2526b3f1f9
2017-05-24 11:29:08 -07:00
Yi Wu
07bdcb91fe New WriteImpl to pipeline WAL/memtable write
Summary:
PipelineWriteImpl is an alternative approach to WriteImpl. In WriteImpl, only one thread is allow to write at the same time. This thread will do both WAL and memtable writes for all write threads in the write group. Pending writers wait in queue until the current writer finishes. In the pipeline write approach, two queue is maintained: one WAL writer queue and one memtable writer queue. All writers (regardless of whether they need to write WAL) will still need to first join the WAL writer queue, and after the house keeping work and WAL writing, they will need to join memtable writer queue if needed. The benefit of this approach is that
1. Writers without memtable writes (e.g. the prepare phase of two phase commit) can exit write thread once WAL write is finish. They don't need to wait for memtable writes in case of group commit.
2. Pending writers only need to wait for previous WAL writer finish to be able to join the write thread, instead of wait also for previous memtable writes.

Merging #2056 and #2058 into this PR.
Closes https://github.com/facebook/rocksdb/pull/2286

Differential Revision: D5054606

Pulled By: yiwu-arbug

fbshipit-source-id: ee5b11efd19d3e39d6b7210937b11cefdd4d1c8d
2017-05-19 14:26:42 -07:00
Mikhail Antonov
ba685a472a Support ingest_behind for IngestExternalFile
Summary:
First cut for early review; there are few conceptual points to answer and some code structure issues.

For conceptual points -

 - restriction-wise, we're going to disallow ingest_behind if (use_seqno_zero_out=true || disable_auto_compaction=false), the user is responsible to properly open and close DB with required params
 - we wanted to ingest into reserved bottom most level. Should we fail fast if bottom level isn't empty, or should we attempt to ingest if file fits there key-ranges-wise?
 - Modifying AssignLevelForIngestedFile seems the place we we'd handle that.

On code structure - going to refactor GenerateAndAddExternalFile call in the test class to allow passing instance of IngestionOptions, that's just going to incur lots of changes at callsites.
Closes https://github.com/facebook/rocksdb/pull/2144

Differential Revision: D4873732

Pulled By: lightmark

fbshipit-source-id: 81cb698106b68ef8797f564453651d50900e153a
2017-05-17 11:42:42 -07:00
Siying Dong
d616ebea23 Add GPLv2 as an alternative license.
Summary: Closes https://github.com/facebook/rocksdb/pull/2226

Differential Revision: D4967547

Pulled By: siying

fbshipit-source-id: dd3b58ae1e7a106ab6bb6f37ab5c88575b125ab4
2017-04-27 18:06:12 -07:00
Dmitri Smirnov
cdad04b051 Remove double buffering on RandomRead on Windows.
Summary:
Remove double buffering on RandomRead on Windows.
  With more logic appear in file reader/write Read no longer
  obeys forwarding calls to Windows implementation.
  Previously direct_io (unbuffered) was only available on Windows
  but now is supported as generic.
  We remove intermediate buffering on Windows.
  Remove random_access_max_buffer_size option which was windows specific.
  Non-zero values for that opton introduced unnecessary lock contention.
  Remove Env::EnableReadAhead(), Env::ShouldForwardRawRequest() that are
  no longer necessary.
  Add aligned buffer reads for cases when requested reads exceed read ahead size.
Closes https://github.com/facebook/rocksdb/pull/2105

Differential Revision: D4847770

Pulled By: siying

fbshipit-source-id: 8ab48f8e854ab498a4fd398a6934859792a2788f
2017-04-27 12:30:05 -07:00
Aaron Gao
44fa8ece9b change use_direct_writes to use_direct_io_for_flush_and_compaction
Summary:
Replace Options::use_direct_writes with Options::use_direct_io_for_flush_and_compaction
Now if Options::use_direct_io_for_flush_and_compaction = true, we will enable direct io for both reads and writes for flush and compaction job. Whereas Options::use_direct_reads controls user reads like iterator and Get().
Closes https://github.com/facebook/rocksdb/pull/2117

Differential Revision: D4860912

Pulled By: lightmark

fbshipit-source-id: d93575a8a5e780cf7e40797287edc425ee648c19
2017-04-13 16:12:04 -07:00
Siying Dong
d2dce5611a Move some files under util/ to separate dirs
Summary:
Move some files under util/ to new directories env/, monitoring/ options/ and cache/
Closes https://github.com/facebook/rocksdb/pull/2090

Differential Revision: D4833681

Pulled By: siying

fbshipit-source-id: 2fd8bef
2017-04-05 19:09:16 -07:00