https://dev.mysql.com/innodb-online-ddl-limitations.html
The ALTER TABLE clause LOCK=NONE is not permitted if there are ON...CASCADE or ON...SET NULL constraints on the table. The following limitations apply to online DDL operations: The table is copied when creating an index on a TEMPORARY TABLE. Before ...
https://dev.mysql.com/innodb-online-ddl-single-multi.html
Before the introduction of online DDL, it was common practice to combine many DDL operations into a single ALTER TABLE statement. Because each ALTER TABLE statement involved copying and rebuilding the table, it was more efficient to make several ...
https://dev.mysql.com/innodb-persistent-stats.html
The persistent optimizer statistics feature improves plan stability by storing statistics to disk and making them persistent across server restarts so that the optimizer is more likely to make consistent choices each time for a given query.
https://dev.mysql.com/innodb-temporary-tablespace.html
row *************************** FILE_NAME: ./ibtmp1 TABLESPACE_NAME: innodb_temporary ENGINE: InnoDB INITIAL_SIZE: 12582912 TotalSizeBytes: 12582912 DATA_FREE: 6291456 MAXIMUM_SIZE: NULL TotalSizeBytes shows the current size of the global temporary ... InnoDB uses session temporary tablespaces and a global temporary ...
https://dev.mysql.com/innodb-transaction-scheduling.html
A transaction that is not waiting for a lock reports a NULL TRX_SCHEDULE_WEIGHT value. InnoDB uses the Contention-Aware Transaction Scheduling (CATS) algorithm to prioritize transactions that are waiting for locks. When multiple transactions are ...
https://dev.mysql.com/insert-on-duplicate.html
The VALUES() function is meaningful only in the ON DUPLICATE KEY UPDATE clause or INSERT statements and returns NULL otherwise. If you specify an ON DUPLICATE KEY UPDATE clause and a row to be inserted would cause a duplicate value in a UNIQUE ...
https://dev.mysql.com/internal-temporary-tables.html
In some cases, the server creates internal temporary tables while processing statements. The server creates temporary tables under conditions such as these: Evaluation of UNION statements, with some exceptions described later. Evaluation of some ...
https://dev.mysql.com/kill.html
KILL [CONNECTION | QUERY] processlist_id Each connection to mysqld runs in a separate thread. Thread processlist identifiers can be determined from the ID column of the INFORMATION_SCHEMA PROCESSLIST table, the Id column of SHOW PROCESSLIST output, ...
https://dev.mysql.com/known-issues.html
SELECT statements that insert zero or NULL values into an AUTO_INCREMENT column. This section lists known issues in recent versions of MySQL. For information about platform-specific issues, see the installation and porting instructions in Section ...
https://dev.mysql.com/literals.html
These include strings, numbers, hexadecimal and bit values, boolean values, and NULL. This section describes how to write literal values in MySQL. The section also covers various nuances that you may encounter when dealing with these basic types in ...
