MyRocks is available in
Facebook's (FB) MySQL branch (originally based on MySQL 5.6)
MariaDB (from 10.2 and 10.3)
Percona Server from 5.7
This page lists differences between these variants.
This is a work in progress. The contents are not final
FB and Percona store RocksdDB files in $datadir/.rocksdb
. MariaDB puts them in $datadir/#rocksdb
. This is more friendly for packaging and OS scripts.
FB's branch doesn't provide binaries. One needs to compile it with appropriate compression libraries.
In MariaDB, available compression algorithms can be seen in the rocksdb_supported_compression_types variable. From MariaDB 10.7, algorithms can be installed as a plugin. In earlier versions, the set of supported compression algorithms depends on the platform.
On Ubuntu 16.04 (current LTS) it is Snappy,Zlib,LZ4,LZ4HC
.
On CentOS 7.4 it is Snappy,Zlib
.
In the bintar tarball it is Snappy,Zlib
.
Percona Server supports: Zlib, ZSTD, LZ4 (the default), LZ4HC
. Unsupported algorithms: Snappy, BZip2, XPress
.
FB's branch provides the rocksdb_git_hash
status variable.
MariaDB provides the @@rocksdb_git_hash
system variable.
Percona Server doesn't provide either.
Facebook's branch uses RocksDB 5.10.0 (the version number can be found in include/rocksdb/version.h
)
commit ba295cda29daee3ffe58549542804efdfd969784
Author: Andrew Kryczka <andrewkr@fb.com>
Date: Fri Jan 12 11:03:55 2018 -0800
MariaDB currently uses 5.8.0
commit 9a970c81af9807071bd690f4c808c5045866291a
Author: Yi Wu <yiwu@fb.com>
Date: Wed Sep 13 17:21:35 2017 -0700
Percona Server uses 5.8.0
commit ab0542f5ec6e7c7e405267eaa2e2a603a77d570b
Author: Maysam Yabandeh <myabandeh@fb.com>
Date: Fri Sep 29 07:55:22 2017 -0700
FB branch provides information_schema.rocksdb_global_info type=BINLOG, NAME={FILE, POS, GTID}.
Percona Server doesn't provide it.
MariaDB doesn't provide it.
One use of that information is to take the output of myrocks_hotbackup
and make it a new master.
FB branch has a "Gap Lock Detector" feature. It is at the SQL layer. It can be controlled with gap_lock_XXX
variables and is disabled by default (gap-lock-raise-error=false, gap-lock-write-lock=false).
Percona Server has gap lock checking ON but doesn't seem to have any way to control it? Queries that use Gap Lock on MyRocks fail with an error like this:
INSERT INTO tbl2 SELECT * FROM tbl1;
ERROR 1105 (HY000): Using Gap Lock without full unique key in multi-table or multi-statement transactions
is not allowed. You need to either rewrite queries to use all unique key columns in WHERE equal conditions,
or rewrite to single-table, single-statement transaction. Query: insert into tbl2 select * from tbl1
MariaDB doesn't include the Gap Lock Detector.
Both MariaDB and Percona Server support generated columns, but neither one supports them for the MyRocks storage engine (attempts to create a table will produce an error).
Invisible columns in MariaDB 10.3 are supported (as they are an SQL layer feature).
Facebook's branch has a performance feature for replication slaves, rpl_skip_tx_api
. It is not available in MariaDB or in Percona Server.
The above comparison was made using
FB/MySQL 5.6.35
Percona Server 5.7.20-19-log
MariaDB 10.2.13 (MyRocks is beta)
This page is licensed: CC BY-SA / Gnu FDL