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https://dev.mysql.com/doc/refman/8.4/en/index-extensions.html
InnoDB automatically extends each secondary index by appending the primary key columns to it. Consider this table definition: CREATE TABLE t1 ( i1 INT NOT NULL DEFAULT 0, i2 INT NOT NULL DEFAULT 0, d DATE DEFAULT NULL, PRIMARY KEY (i1, i2), INDEX ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-processlist-table.html
Important INFORMATION_SCHEMA.PROCESSLIST is deprecated and subject to removal in a future MySQL release. As such, the implementation of SHOW PROCESSLIST which uses this table is also deprecated. It is recommended to use the Performance Schema ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-tables-table.html
The information_schema_stats_expiry system variable defines the period of time before cached table statistics expire. If there are no cached statistics or statistics have expired, statistics are retrieved from storage engines when querying table ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-deadlocks-handling.html
This section builds on the conceptual information about deadlocks in Section 17.7.5.2, “Deadlock Detection”. It explains how to organize database operations to minimize deadlocks and the subsequent error handling required in applications.
https://dev.mysql.com/doc/refman/8.4/en/innodb-fulltext-index.html
Full-text indexes are created on text-based columns (CHAR, VARCHAR, or TEXT columns) to speed up queries and DML operations on data contained within those columns. A full-text index is defined as part of a CREATE TABLE statement or added to an ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-information-schema-files-table.html
The Information Schema FILES table provides metadata about all InnoDB tablespace types including file-per-table tablespaces, general tablespaces, the system tablespace, temporary table tablespaces, and undo tablespaces (if present). For more ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-next-key-locking.html
The so-called phantom problem occurs within a transaction when the same query produces different sets of rows at different times. For example, if a SELECT is executed twice, but returns a row the second time that was not returned the first time, ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-performance-ro-txn.html
InnoDB can avoid the overhead associated with setting up the transaction ID (TRX_ID field) for transactions that are known to be read-only. A transaction ID is only needed for a transaction that might perform write operations or locking reads such ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-row-format.html
The row format of a table determines how its rows are physically stored, which in turn can affect the performance of queries and DML operations. As more rows fit into a single disk page, queries and index lookups can work faster, less cache memory ...
https://dev.mysql.com/doc/refman/8.4/en/json-creation-functions.html
The functions listed in this section compose JSON values from component elements. JSON_ARRAY([val[, val] ...]) Evaluates a (possibly empty) list of values and returns a JSON array containing those values. mysql> SELECT JSON_ARRAY(1, "abc", NULL, ...