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MariaDB server is a community developed fork of MySQL server. Started by core members of the original MySQL team, MariaDB actively works with outside developers to deliver the most featureful, stable, and sanely licensed open SQL server in the industry.
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Marko Mäkelä bd5a6403ca MDEV-26033: Race condition between buf_pool.page_hash and resize() 
The replacement of buf_pool.page_hash with a different type of
hash table in commit 5155a300fa (MDEV-22871)
introduced a race condition with buffer pool resizing.

We have an execution trace where buf_pool.page_hash.array is changed
to point to something else while page_hash_latch::read_lock() is
executing. The same should also affect page_hash_latch::write_lock().

We fix the race condition by never resizing (and reallocating) the
buf_pool.page_hash. We assume that resizing the buffer pool is
a rare operation. Yes, there might be a performance regression if a
server is first started up with a tiny buffer pool, which is later
enlarged. In that case, the tiny buf_pool.page_hash.array could cause
increased use of the hash bucket lists. That problem can be worked
around by initially starting up the server with a larger buffer pool
and then shrinking that, until changing to a larger size again.

buf_pool_t::resize_hash(): Remove.

buf_pool_t::page_hash_table::lock(): Do not attempt to deal with
hash table resizing. If we really wanted that in a safe manner,
we would probably have to introduce a global rw-lock around the
operation, or at the very least, poll buf_pool.resizing, both of
which would be detrimental to performance.
2021-07-03 13:58:38 +03:00
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BUILD
client Merge 10.4 into 10.5 2021-06-21 14:22:22 +03:00
cmake Merge 10.4 into 10.5 2021-07-02 16:19:25 +03:00
dbug
debian Merge 10.4 into 10.5 2021-06-08 16:03:53 +03:00
Docs
extra Merge 10.4 into 10.5 2021-06-21 14:22:22 +03:00
include MDEV-26010 fixup: Use acquire/release memory order 2021-06-26 11:16:40 +03:00
libmariadb@802ce584a2 update libmariadb 2021-06-14 23:45:31 +02:00
libmysqld
libservices
man
mysql-test MDEV-23004 When using GROUP BY with JSON_ARRAYAGG with joint table, the square brackets are not included 2021-07-02 16:23:48 +03:00
mysys MDEV-26042 Atomic write capability is not detected correctly 2021-06-29 15:04:27 +03:00
mysys_ssl
plugin
randgen/conf
scripts Merge 10.4 into 10.5 2021-07-02 13:02:26 +03:00
sql Merge 10.4 into 10.5 2021-07-02 13:02:26 +03:00
sql-bench
sql-common
storage MDEV-26033: Race condition between buf_pool.page_hash and resize() 2021-07-03 13:58:38 +03:00
strings
support-files Merge 10.3 into 10.4 2021-06-21 12:38:25 +03:00
tests
tpool MDEV-25953 Tpool - prevent potential deadlock in simulated AIO 2021-06-17 20:39:47 +02:00
unittest
vio
win Merge 10.4 into 10.5 2021-06-08 16:03:53 +03:00
wsrep-lib@85b8150321
zlib
.clang-format
.gitattributes
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config.h.cmake
configure.cmake
CONTRIBUTING.md
COPYING
CREDITS
INSTALL-SOURCE
INSTALL-WIN-SOURCE
KNOWN_BUGS.txt
README.md Merge 10.4 into 10.5 2021-06-21 14:22:22 +03:00
THIRDPARTY
VERSION bump the VERSION 2021-06-22 23:00:01 -04:00

README.md

Code status:

  • Appveyor CI status ci.appveyor.com

MariaDB: The open source relational database

MariaDB was designed as a drop-in replacement of MySQL(R) with more features, new storage engines, fewer bugs, and better performance.

MariaDB is brought to you by the MariaDB Foundation and the MariaDB Corporation. Please read the CREDITS file for details about the MariaDB Foundation, and who is developing MariaDB.

MariaDB is developed by many of the original developers of MySQL who now work for the MariaDB Corporation, the MariaDB Foundation and by many people in the community.

MySQL, which is the base of MariaDB, is a product and trademark of Oracle Corporation, Inc. For a list of developers and other contributors, see the Credits appendix. You can also run 'SHOW authors' to get a list of active contributors.

A description of the MariaDB project and a manual can be found at:

https://mariadb.org

https://mariadb.com/kb/en/

https://mariadb.com/kb/en/mariadb-vs-mysql-features/

https://mariadb.com/kb/en/mariadb-versus-mysql-compatibility/

https://mariadb.com/kb/en/new-and-old-releases/

Help

More help is available from the Maria Discuss mailing list https://launchpad.net/~maria-discuss, MariaDB's Zulip instance, https://mariadb.zulipchat.com/ and the #maria IRC channel on Freenode.

Live QA for beginner contributors

MariaDB has a dedicated time each week when we answer new contributor questions live on Zulip and IRC. From 8:00 to 10:00 UTC on Mondays, and 10:00 to 12:00 UTC on Thursdays, anyone can ask any questions they’d like, and a live developer will be available to assist.

New contributors can ask questions any time, but we will provide immediate feedback during that interval.

Licensing

NOTE:

MariaDB is specifically available only under version 2 of the GNU General Public License (GPLv2). (I.e. Without the "any later version" clause.) This is inherited from MySQL. Please see the README file in the MySQL distribution for more information.

License information can be found in the COPYING file. Third party license information can be found in the THIRDPARTY file.

Bug Reports

Bug and/or error reports regarding MariaDB should be submitted at: https://jira.mariadb.org

For reporting security vulnerabilities see: https://mariadb.org/about/security-policy/

The code for MariaDB, including all revision history, can be found at: https://github.com/MariaDB/server