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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Sergei Petrunia 43c5d1303f MDEV-35958 Cost estimates for materialized derived tables are poor
Backport of commit 74f70c3944 to 10.11.
The new logic is disabled by default, to enable, use
optimizer_adjust_secondary_key_costs=fix_derived_table_read_cost.

== Original commit comment ==
Fixed costs in JOIN_TAB::estimate_scan_time() and HEAP

Estimate_scan_time() calculates the cost of scanning a derivied table.
The old code did not take into account that the temporary table heap table
may be converted to Aria.

  Things fixed:
  - Added checking if the temporary tables data will fit in the heap.
    If not, then calculate the cost based on the designated internal
    temporary table engine (Aria).
  - Removed MY_MAX(records, 1000) and instead trust the optimizer's
    estimate of records. This reduces the cost of temporary tables a bit
    for small tables, which caused a few changes in mtr results.
  - Fixed cost calculation for HEAP.
  - HEAP costs->row_next_find_cost was not set. This does not affect old
    costs calculation as this cost slot was not used anywhere.
    Now HEAP cost->row_next_find_cost is set, which allowed me to remove
    some duplicated computation in ha_heap::scan_time()
2025-02-10 21:14:01 +02:00
.github Merge 10.6 into 10.9 2023-05-19 15:11:06 +03:00
BUILD Merge branch '10.6' into 10.11 2024-04-26 08:02:49 +02:00
client Merge branch '10.6' into 10.11 2025-01-30 11:55:13 +01:00
cmake Merge branch '10.6' into 10.11 2025-01-30 11:55:13 +01:00
dbug Merge 10.6 into 10.8 2023-02-10 13:43:53 +02:00
debian Merge branch '10.6' into 10.11 2025-01-30 11:55:13 +01:00
Docs Merge 10.4 into 10.5 2022-09-26 13:34:38 +03:00
extra Merge branch '10.6' into 10.11 2025-01-30 11:55:13 +01:00
include Merge branch '10.6' into 10.11 2025-01-30 11:55:13 +01:00
libmariadb@2d56f340c4 C/C 3.3.14 2025-01-29 10:44:18 +01:00
libmysqld Merge branch '10.6' into 10.11 2025-01-30 11:55:13 +01:00
libservices Merge 10.6 into 10.11 2024-02-08 15:04:46 +02:00
man Merge branch '10.6' into 10.11 2024-07-22 15:14:50 +02:00
mysql-test MDEV-35958 Cost estimates for materialized derived tables are poor 2025-02-10 21:14:01 +02:00
mysys MDEV-36056 Fix VS2019 compilation 2025-02-10 15:27:08 +01:00
mysys_ssl MDEV-35838 libressl support differences in CRYPTO_set_mem_functions 2025-01-14 12:13:22 +11:00
plugin Merge branch '10.6' into 10.11 2025-01-30 11:55:13 +01:00
randgen/conf
scripts Merge 10.6 into 10.11 2025-01-08 12:51:26 +02:00
sql MDEV-35958 Cost estimates for materialized derived tables are poor 2025-02-10 21:14:01 +02:00
sql-bench Updated sql-bench to run with PostgreSQL 14.9 2023-09-09 15:14:45 +03:00
sql-common Merge branch '10.6' into 10.11 2025-01-30 11:55:13 +01:00
storage MDEV-36056 Fix VS2019 compilation 2025-02-10 15:27:08 +01:00
strings Merge branch '10.6' into 10.11 2025-01-30 11:55:13 +01:00
support-files Merge 10.6 into 10.11 2024-11-29 13:43:17 +02:00
tests Merge 10.6 into 10.11 2025-01-02 12:39:56 +02:00
tpool Merge 10.6 into 10.11 2025-01-08 12:51:26 +02:00
unittest Merge 10.6 into 10.11 2024-12-19 15:38:53 +02:00
vio Merge 10.6 into 10.11 2024-10-03 10:55:08 +03:00
win Merge branch '10.6' into 10.11 2025-01-30 11:55:13 +01:00
wsrep-lib@70cd967f5e galera: wsrep-lib submodule update 2024-12-17 09:53:19 +01:00
zlib Merge branch 'merge-zlib' (1.3.1) into 10.4 2024-04-26 13:50:03 +02:00
.clang-format Remove duplicate key "Language" from .clang-format 2024-04-17 16:52:37 +02:00
.gitattributes Merge branch '10.5' into 10.6 2022-02-03 17:01:31 +01:00
.gitignore Merge 10.6 into 10.11 2024-10-03 10:55:08 +03:00
.gitlab-ci.yml Merge branch '10.6' into 10.11 2024-07-22 15:14:50 +02:00
.gitmodules Merge remote-tracking branch '10.4' into 10.5 2023-03-31 21:32:41 +02:00
appveyor.yml Merge 10.5 into 10.6 2024-06-07 10:03:51 +03:00
BUILD-CMAKE Minor spelling fixes in code comments, docs and output 2018-01-12 16:49:02 +02:00
CMakeLists.txt Merge branch '10.6' into 10.11 2025-01-30 11:55:13 +01:00
config.h.cmake Merge branch '10.6' into 10.11 2024-10-29 15:24:38 +01:00
configure.cmake Merge branch '10.6' into 10.11 2024-10-29 15:24:38 +01:00
CONTRIBUTING.md Remove mention of Freenode 2021-09-22 07:15:08 +02:00
COPYING Update FSF Address 2019-05-11 21:29:06 +03:00
CREDITS Update sponsors 2024-08-12 09:32:30 +01:00
INSTALL-SOURCE Update AskMonty and Atlassian references to MariaDB 2016-03-08 15:24:01 +02:00
INSTALL-WIN-SOURCE Update AskMonty and Atlassian references to MariaDB 2016-03-08 15:24:01 +02:00
KNOWN_BUGS.txt Changed some MySQL names in messages to MariaDB 2018-12-09 20:49:05 +02:00
README.md Update README for branch choice 2024-05-29 13:49:32 +01:00
THIRDPARTY Merge branch '10.6' into 10.11 2024-02-01 18:36:14 +01:00
VERSION bump the VERSION 2025-02-04 11:18:48 -05:00

Code status:

  • Appveyor CI status ci.appveyor.com

MariaDB: The innovative open source 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/

Getting the code, building it and testing it

Refer to the following guide: https://mariadb.org/get-involved/getting-started-for-developers/get-code-build-test/ which outlines how to build the source code correctly and run the MariaDB testing framework, as well as which branch to target for your contributions.

Help

More help is available from the Maria Discuss mailing list https://lists.mariadb.org/postorius/lists/discuss.lists.mariadb.org/ and MariaDB's Zulip instance, https://mariadb.zulipchat.com/

Licensing


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