Summary:
Add option and plugin rate limiter for PosixWritableFile. The rate
limiter only applies to flush and compaction. WAL and MANIFEST are
excluded from this enforcement.
Test Plan: db_test
Reviewers: igor, yhchiang, sdong
Reviewed By: sdong
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D19425
Summary:
A generic rate limiter that can be shared by threads and rocksdb
instances. Will use this to smooth out write traffic generated by
compaction and flush. This will help us get better p99 behavior on flash
storage.
Test Plan:
unit test output
==== Test RateLimiterTest.Rate
request size [1 - 1023], limit 10 KB/sec, actual rate: 10.374969 KB/sec, elapsed 2002265
request size [1 - 2047], limit 20 KB/sec, actual rate: 20.771242 KB/sec, elapsed 2002139
request size [1 - 4095], limit 40 KB/sec, actual rate: 41.285299 KB/sec, elapsed 2202424
request size [1 - 8191], limit 80 KB/sec, actual rate: 81.371605 KB/sec, elapsed 2402558
request size [1 - 16383], limit 160 KB/sec, actual rate: 162.541268 KB/sec, elapsed 3303500
Reviewers: yhchiang, igor, sdong
Reviewed By: sdong
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D19359
Summary: stackable_db doesn't have GetLiveFilesMetaData() implemented. Add it
Test Plan: make all check
Reviewers: yhchiang, ljin, igor
Reviewed By: igor
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D19491
Summary:
This diff allows the I/O stats about Flush and Compaction to be reported
in a more accurate way. Instead of measuring the size of a file, it
measure I/O cost in per read / write basis.
Test Plan: make all check
Reviewers: sdong, igor, ljin
Reviewed By: ljin
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D19383
Summary:
This diff adds timeout_hint_us to WriteOptions. If it's non-zero, then
1) writes associated with this options MAY be aborted when it has been
waiting for longer than the specified time. If an abortion happens,
associated writes will return Status::TimeOut.
2) the stall time of the associated write caused by flush or compaction
will be limited by timeout_hint_us.
The default value of timeout_hint_us is 0 (i.e., OFF.)
The statistics of timeout writes will be recorded in WRITE_TIMEDOUT.
Test Plan:
export ROCKSDB_TESTS=WriteTimeoutAndDelayTest
make db_test
./db_test
Reviewers: igor, ljin, haobo, sdong
Reviewed By: sdong
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D18837
Summary:
In this patch, we allow RocksDB to support multiple DB paths internally.
No user interface is supported yet so this patch is silent to users.
Test Plan: make all check
Reviewers: igor, haobo, ljin, yhchiang
Reviewed By: yhchiang
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D18921
Summary:
In this patch, we enhance HashLinkList memtable to reduce performance outliers when a bucket contains too many entries. We switch to skip list for this case to enable binary search.
Add threshold_use_skiplist parameter to determine when a bucket needs to switch to skip list.
The new data structure is documented in comments in the codes.
Test Plan:
make all check
set threshold_use_skiplist in several tests
Reviewers: yhchiang, haobo, ljin
Reviewed By: yhchiang, ljin
Subscribers: nkg-, xjin, dhruba, yhchiang, leveldb
Differential Revision: https://reviews.facebook.net/D19299
Summary: It seems to me that when ever function MemTableRep::GetIterator(const Slice& slice) is used, we can use MemTableRep::GetDynamicPrefixIterator() instead. Just delete it to simplify the codes.
Test Plan: make all check
Reviewers: yhchiang, ljin
Reviewed By: ljin
Subscribers: xjin, dhruba, haobo, leveldb
Differential Revision: https://reviews.facebook.net/D19281
Summary: Currently ldb tool dump keys either in ascii format or hex format - neither is ideal if the key has a binary structure and is not readable in ascii. This diff also allows LDB tool to be customized in ways beyond DB options.
Test Plan: verify that key formatter works with some simple db with binary key.
Reviewers: sdong, ljin
Reviewed By: ljin
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D19209
Summary:
After evaluating options for JSON storage, I decided to implement our own. The reason is that we'll be able to optimize it better and we get to reduce unnecessary dependencies (which is what we'd get with folly).
I also plan to write a serializer/deserializer for JSONDocument with our own binary format similar to BSON. That way we'll store binary JSON format in RocksDB instead of the plain-text JSON. This means less storage and faster deserialization.
There are still some inefficiencies left here. I plan to optimize them after we develop a functioning DocumentDB. That way we can move and iterate faster.
Test Plan: added a unit test
Reviewers: dhruba, haobo, sdong, ljin, yhchiang
Reviewed By: haobo
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D18831
Summary:
As discussed in our internal group, we don't get much use of seek compaction at the moment, while it's making code more complicated and slower in some cases.
This diff removes seek compaction and (hopefully) all code that was introduced to support seek compaction.
There is one test case that relied on didIO information. I'll try to find another way to implement it.
Test Plan: make check
Reviewers: sdong, haobo, yhchiang, ljin, dhruba
Reviewed By: ljin
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D19161
Summary:
Add a encoding feature of PlainTable to encode PlainTable's keys to save some bytes for the same prefixes.
The data format is documented in table/plain_table_factory.h
Test Plan: Add unit test coverage in plain_table_db_test
Reviewers: yhchiang, igor, dhruba, ljin, haobo
Reviewed By: haobo
Subscribers: nkg-, leveldb
Differential Revision: https://reviews.facebook.net/D18735
Summary:
Currently, the in-memory hash index of blockbased table uses a precise hash map to track the prefix to block range mapping. In some use cases, especially when prefix itself is big, the memory overhead becomes a problem. This diff introduces a fixed hash bucket array that does not store the prefix and allows prefix collision, which is similar to the plaintable hash index, in order to reduce the memory consumption.
Just a quick draft, still testing and refining.
Test Plan: unit test and shadow testing
Reviewers: dhruba, kailiu, sdong
Reviewed By: sdong
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D19047
Summary:
This is minor, but if we put the writing talbe factory as the third parameter, when we add a new table format, we'll have a situation:
1) block based factory
2) plain table factory
3) output factory
4) new format factory
I think it makes more sense to have output as the first parameter.
Also, fixed a NewAdaptiveTableFactory() call in unit test
Test Plan: unit test
Reviewers: sdong
Reviewed By: sdong
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D19119
Summary: Add two parameters of hash linked list to log distribution of number of entries across all buckets, and a sample row when there are too many entries in one single bucket.
Test Plan: Turn it on in plain_table_db_test and see the logs.
Reviewers: haobo, ljin
Reviewed By: ljin
Subscribers: leveldb, nkg-, dhruba, yhchiang
Differential Revision: https://reviews.facebook.net/D19095
Summary: The new table factory is used if users want to convert a DB from one table format to the other. A user can use this table to open a DB written using one table format and write new files to another table format.
Test Plan: add a unit test
Reviewers: haobo, igor
Reviewed By: igor
Subscribers: dhruba, ljin, yhchiang, leveldb
Differential Revision: https://reviews.facebook.net/D19017
Summary: Include max_write_buffer_number >= 2 to SanitizeOptions.
Test Plan: make all check
Reviewers: haobo, sdong, igor, ljin
Reviewed By: ljin
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D19077
Summary: This is a temporary solution to a issue that we have with compression libraries. See task #4453446.
Test Plan: make check doesn't complain :)
Reviewers: haobo, ljin, yhchiang, dhruba, sdong
Reviewed By: sdong
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D18975
Summary: Provide an convenience option to create column families if they are missing from the DB. Task #4460490
Test Plan: added unit test. also, stress test for some time
Reviewers: sdong, haobo, dhruba, ljin, yhchiang
Reviewed By: yhchiang
Subscribers: yhchiang, leveldb
Differential Revision: https://reviews.facebook.net/D18951
Summary:
In this patch, try to allocate the whole iterator tree starting from DBIter from an arena
1. ArenaWrappedDBIter is created when serves as the entry point of an iterator tree, with an arena in it.
2. Add an option to create iterator from arena for following iterators: DBIter, MergingIterator, MemtableIterator, all mem table's iterators, all table reader's iterators and two level iterator.
3. MergeIteratorBuilder is created to incrementally build the tree of internal iterators. It is passed to mem table list and version set and add iterators to it.
Limitations:
(1) Only DB::NewIterator() without tailing uses the arena. Other cases, including readonly DB and compactions are still from malloc
(2) Two level iterator itself is allocated in arena, but not iterators inside it.
Test Plan: make all check
Reviewers: ljin, haobo
Reviewed By: haobo
Subscribers: leveldb, dhruba, yhchiang, igor
Differential Revision: https://reviews.facebook.net/D18513
Summary:
This patch changes meaning of options.bloom_locality: 0 means disable cache line optimization and any positive number means use CACHE_LINE_SIZE as block size (the previous behavior is the block size will be CACHE_LINE_SIZE*options.bloom_locality). By doing it, the divide operations inside a block can be replaced by a shift.
Performance is improved:
https://reviews.facebook.net/P471
Also, improve the basic algorithm in two ways:
(1) make sure num of blocks is an odd number
(2) rotate bytes after every probe in locality mode. Since the divider is 2^n, unless doing it, we are never able to use all the bits.
Improvements of false positive: https://reviews.facebook.net/P459
Test Plan: make all check
Reviewers: ljin, haobo
Reviewed By: haobo
Subscribers: dhruba, yhchiang, igor, leveldb
Differential Revision: https://reviews.facebook.net/D18843
Summary:
Introducing new compaction style -- FIFO.
FIFO compaction style has write amplification of 1 (+1 for WAL) and it deletes the oldest files when the total DB size exceeds pre-configured values.
FIFO compaction style is suited for storing high-frequency event logs.
Test Plan: Added a unit test
Reviewers: dhruba, haobo, sdong
Reviewed By: dhruba
Subscribers: alberts, leveldb
Differential Revision: https://reviews.facebook.net/D18765
Summary:
This diff addresses task #4296714 and rethinks how users provide us with TablePropertiesCollectors as part of Options.
Here's description of task #4296714:
I'm debugging #4295529 and noticed that our count of user properties kDeletedKeys is wrong. We're sharing one single InternalKeyPropertiesCollector with all Table Builders. In LOG Files, we're outputting number of kDeletedKeys as connected with a single table, while it's actually the total count of deleted keys since creation of the DB.
For example, this table has 3155 entries and 1391828 deleted keys.
The problem with current approach that we call methods on a single TablePropertiesCollector for all the tables we create. Even worse, we could do it from multiple threads at the same time and TablePropertiesCollector has no way of knowing which table we're calling it for.
Good part: Looks like nobody inside Facebook is using Options::table_properties_collectors. This means we should be able to painfully change the API.
In this change, I introduce TablePropertiesCollectorFactory. For every table we create, we call `CreateTablePropertiesCollector`, which creates a TablePropertiesCollector for a single table. We then use it sequentially from a single thread, which means it doesn't have to be thread-safe.
Test Plan:
Added a test in table_properties_collector_test that fails on master (build two tables, assert that kDeletedKeys count is correct for the second one).
Also, all other tests
Reviewers: sdong, dhruba, haobo, kailiu
Reviewed By: kailiu
CC: leveldb
Differential Revision: https://reviews.facebook.net/D18579
Summary:
This diff is addressing multiple things with a single goal -- to make RocksDB easier to use:
* Add some functions to Options that make RocksDB easier to tune.
* Add example code for both simple RocksDB and RocksDB with Column Families.
* Rewrite our README.md
Regarding Options, I took a stab at something we talked about for a long time:
* https://www.facebook.com/groups/rocksdb.dev/permalink/563169950448190/
I added functions:
* IncreaseParallelism() -- easy, increases the thread pool and max_background_compactions
* OptimizeLevelStyleCompaction(memtable_memory_budget) -- the easiest way to optimize rocksdb for less stalls with level style compaction. This is very likely not ideal configuration. Feel free to suggest improvements. I used some of Mark's suggestions from here: https://github.com/facebook/rocksdb/issues/54
* OptimizeUniversalStyleCompaction(memtable_memory_budget) -- optimize for universal compaction.
Test Plan: compiled rocksdb. ran examples.
Reviewers: dhruba, MarkCallaghan, haobo, sdong, yhchiang
Reviewed By: dhruba
CC: leveldb
Differential Revision: https://reviews.facebook.net/D18621
Summary:
TLB page allocation errors are now logged to info logs, instead of stderr.
In order to do that, mem table rep's factory functions take a info logger now.
Test Plan: make all check
Reviewers: haobo, igor, yhchiang
Reviewed By: yhchiang
CC: leveldb, yhchiang, dhruba
Differential Revision: https://reviews.facebook.net/D18471
Summary: added a new option to BackupEngine: if share_files_with_checksum is set to true, sst files are stored in shared_checksum/ and are identified by the triple (file name, checksum, file size) instead of just the file name. This option is targeted at distributed databases that want to backup their primary replica.
Test Plan: unit tests and tested backup and restore on a distributed rocksdb
Reviewers: igor
Reviewed By: igor
Differential Revision: https://reviews.facebook.net/D18393
Summary: Added a method that executes a callback on every cache entry.
Test Plan: added a unit test
Reviewers: haobo
Reviewed By: haobo
CC: leveldb, dhruba
Differential Revision: https://reviews.facebook.net/D18441
Summary:
Added a new option `max_total_wal_size`. Once the total WAL size goes over that, we make an attempt to flush all column families that still have data in the earliest WAL file.
By default, I calculate `max_total_wal_size` dynamically, that should be good-enough for non-advanced customers.
Test Plan: Added a test
Reviewers: dhruba, haobo, sdong, ljin, yhchiang
Reviewed By: haobo
CC: leveldb
Differential Revision: https://reviews.facebook.net/D18345
Summary: Add an option to allocate a piece of memory from huge page TLB. Add options to trigger it in dynamic bloom, plain table indexes andhash linked list hash table.
Test Plan: make all check
Reviewers: haobo, ljin
Reviewed By: haobo
CC: nkg-, dhruba, leveldb, igor, yhchiang
Differential Revision: https://reviews.facebook.net/D18357
Summary:
= Major Changes =
* Add a new mem-table representation, HashCuckooRep, which is based cuckoo hash.
Cuckoo hash uses multiple hash functions. This allows each key to have multiple
possible locations in the mem-table.
- Put: When insert a key, it will try to find whether one of its possible
locations is vacant and store the key. If none of its possible
locations are available, then it will kick out a victim key and
store at that location. The kicked-out victim key will then be
stored at a vacant space of its possible locations or kick-out
another victim. In this diff, the kick-out path (known as
cuckoo-path) is found using BFS, which guarantees to be the shortest.
- Get: Simply tries all possible locations of a key --- this guarantees
worst-case constant time complexity.
- Time complexity: O(1) for Get, and average O(1) for Put if the
fullness of the mem-table is below 80%.
- Default using two hash functions, the number of hash functions used
by the cuckoo-hash may dynamically increase if it fails to find a
short-enough kick-out path.
- Currently, HashCuckooRep does not support iteration and snapshots,
as our current main purpose of this is to optimize point access.
= Minor Changes =
* Add IsSnapshotSupported() to DB to indicate whether the current DB
supports snapshots. If it returns false, then DB::GetSnapshot() will
always return nullptr.
Test Plan:
Run existing tests. Will develop a test specifically for cuckoo hash in
the next diff.
Reviewers: sdong, haobo
Reviewed By: sdong
CC: leveldb, dhruba, igor
Differential Revision: https://reviews.facebook.net/D16155
Lei Jin