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https://dev.mysql.com/doc/relnotes/mysql/8.4/en/news-8-1-0.html
Now, the audit_log plugin is optimized not to use a temporary buffer when JSON-format logging is used. (Bug #35181008) Added the OPTIMIZE_SANITIZER_BUILDS CMake option that adds -O1 -fno-inline to sanitizer builds. Listed here are all operations now ...This new verification setting is a percentage of the total characters in the current ...
https://dev.mysql.com/doc/refman/8.4/en/index-hints.html
Index hints give the optimizer information about how to choose indexes during query processing. Index hints, described here, differ from optimizer hints, described in Section 10.9.3, “Optimizer Hints”. Note MySQL 8.4 supports the index-level ...
https://dev.mysql.com/doc/refman/8.4/en/mysqlcheck.html
The mysqlcheck client performs table maintenance: It checks, repairs, optimizes, or analyzes tables. mysqlcheck uses the SQL statements CHECK TABLE, REPAIR TABLE, ANALYZE TABLE, and OPTIMIZE TABLE in a convenient way for the user. Command Meaning ...Each table is locked and therefore unavailable to other sessions while it is being processed, although for check operations, the table is locked with a READ lock only (see Section 15.3.6, “LOCK TABLES and UNLOCK TABLES Statements”, for more information about READ and WRITE ...
https://dev.mysql.com/doc/relnotes/mysql/8.4/en/news-8-4-0.html
(WL #16017) Optimizer Notes This release adds support for automatic updates of histograms. (Bug #36053241, WL #15786) The multi-range read (MRR) optimization did not perform as well as in previous releases. (WL #16044) Important Change: This release ...(Bug #36301441) Audit log filtering by type, using error as the type, did not work ...
https://dev.mysql.com/doc/heatwave/en/heatwave-errors.html
Error number: 1004; Symbol: HW_ER_QUERY_CANCELLED Message: Query was canceled during HeatWave query optimization. Error number: 1005; Symbol: HW_ER_UNSUPPORTED_QUERY_OPT Message: Currently unsupported HeatWave query optimization scenario. Error ...
https://dev.mysql.com/doc/refman/8.4/en/explain-extended.html
The Message value in SHOW WARNINGS output displays how the optimizer qualifies table and column names in the SELECT statement, what the SELECT looks like after the application of rewriting and optimization rules, and possibly other notes about the ... The EXPLAIN statement produces extra (“extended”) information that is not part of EXPLAIN output but can be viewed by issuing a SHOW WARNINGS statement following ...
https://dev.mysql.com/doc/refman/8.4/en/join.html
Index hints can be specified to affect how the MySQL optimizer makes use of indexes. Optimizer hints and the optimizer_switch system variable are other ways to influence optimizer use of indexes. This includes a join handled by merging derived ...
https://dev.mysql.com/doc/refman/8.4/en/system-schema.html
Data Dictionary Tables Grant System Tables Object Information System Tables Log System Tables Server-Side Help System Tables Time Zone System Tables Replication System Tables Optimizer System Tables Miscellaneous System Tables The remainder of this ...It contains tables that store information required by the MySQL server as it ...
https://dev.mysql.com/doc/relnotes/mysql/8.4/en/news-8-2-0.html
(WL #15755) Optimizer Notes Performance of statements using the set operations EXCEPT and INTERSECT is improved using a new hash table optimization which is enabled automatically for such statements. To cause the optimizer to revert to the temporary ...(Bug #35611072) Authentication Notes The mysql_native_password plugin, which was deprecated previously, now is no longer mandatory and can be disabled at server ...
https://dev.mysql.com/doc/refman/8.4/en/descending-indexes.html
Descending indexes also make it possible for the optimizer to use multiple-column indexes when the most efficient scan order mixes ascending order for some columns and descending order for others. Indexes that have descending key parts are not used ... MySQL supports descending indexes: DESC in an index definition is no longer ignored but causes storage of key values in descending ...