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https://dev.mysql.com/doc/refman/5.7/en/information-schema-optimization.html
1) Try to use constant lookup values for database and table names in the WHERE clause You can take advantage of this principle as follows: To look up databases or tables, use expressions that evaluate to a constant, such as literal values, functions ... Applications that monitor databases may make frequent use of INFORMATION_SCHEMA ...
https://dev.mysql.com/doc/refman/5.7/en/myisam-storage-engine.html
This can also be changed by changing the source and recompiling. This is done by automatically combining adjacent deleted blocks and by extending blocks if the next block is deleted. myisamchk --fast checks only those tables that don't have this ...
https://dev.mysql.com/doc/refman/5.7/en/optimizer-hints.html
This occurs due to heuristic pruning during greedy search, which can be avoided by setting optimizer_prune_level=0. Changes to this variable affect execution of all subsequent queries; to affect one query differently from another, it is necessary to ... One means of control over optimizer strategies is to set the optimizer_switch system variable (see Section 8.9.2, “Switchable ...
https://dev.mysql.com/doc/refman/5.7/en/performance-schema-replication-tables.html
This is similar to the information available from the SHOW SLAVE STATUS statement, but representation in table form is more accessible and has usability benefits: SHOW SLAVE STATUS output is useful for visual inspection, but not so much for ...Query ...
https://dev.mysql.com/doc/refman/5.7/en/sorted-index-builds.html
The drawbacks of this “top-down” method of building an index are the cost of searching for an insert position and the constant splitting and merging of B-tree nodes. This method of index creation is also known as a sorted index build. This ...
https://dev.mysql.com/doc/refman/5.7/en/disk-issues.html
This section describes ways to configure storage devices when you can devote more and faster storage hardware to the database server. This problem becomes more apparent when the amount of data starts to grow so large that effective caching becomes ...For information about optimizing an InnoDB configuration to improve I/O performance, see Section 8.5.8, “Optimizing InnoDB Disk ...
https://dev.mysql.com/doc/refman/5.7/en/group-replication-limitations.html
This is because foreign key constraints that result in cascading operations executed by a multi-primary mode group can result in undetected conflicts and lead to inconsistent data across the members of the group. In single-primary mode this is not a ...Note that the limitations and issues described for multi-primary mode groups can also apply in single-primary mode clusters during a failover event, while the newly elected primary flushes out its applier queue from the old ...
https://dev.mysql.com/doc/refman/5.7/en/index-extensions.html
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 k_d (d) ) ENGINE = InnoDB; This table defines the primary key on columns (i1, i2). It also ...
https://dev.mysql.com/doc/refman/5.7/en/information-schema-innodb-sys-tablestats-table.html
This data is used by the MySQL optimizer to calculate which index to use when querying an InnoDB table. This information is derived from in-memory data structures rather than data stored on disk. InnoDB tables are represented in this view if they ...
https://dev.mysql.com/doc/refman/5.7/en/myisam-repair.html
The discussion in this section describes how to use myisamchk on MyISAM tables (extensions .MYI and .MYD). In this case, you must use ALTER TABLE to increase the MAX_ROWS and AVG_ROW_LENGTH table option values: ALTER TABLE tbl_name MAX_ROWS=xxx ...