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https://dev.mysql.com/doc/refman/8.4/en/nested-join-optimization.html
Access by key from one inner table to another in the same nested join is prohibited if it is induced by a predicate from the WHERE condition. The following discussion refers to the join syntax described in Section 15.2.13.2, “JOIN Clause”. The ...
https://dev.mysql.com/doc/refman/8.4/en/nested-loop-joins.html
MySQL executes joins between tables using a nested-loop algorithm or variations on it. Nested-Loop Join Algorithm Nested-Loop Join Algorithm A simple nested-loop join (NLJ) algorithm reads rows from the first table in a loop one at a time, passing ...
https://dev.mysql.com/doc/refman/8.4/en/optimize-overview.html
The main memory areas to configure are the InnoDB buffer pool and the MyISAM key cache. Balancing Portability and Performance To use performance-oriented SQL extensions in a portable MySQL program, you can wrap MySQL-specific keywords in a statement ... Database performance depends on several factors at the database level, such as tables, queries, and configuration ...
https://dev.mysql.com/doc/refman/8.4/en/optimizer-statistics.html
Here is a sample histogram object: { "buckets": [ [ 1, 0.3333333333333333 ], [ 2, 0.6666666666666666 ], [ 3, 1 ] ], "null-values": 0, "last-updated": "2017-03-24 13:32:40.000000", "sampling-rate": 1, "histogram-type": "singleton", ... The ...
https://dev.mysql.com/doc/refman/8.4/en/optimizing-innodb-diskio.html
binlog_row_image If binary logs are on non-rotational storage and all tables have primary keys, consider setting this option to minimal to reduce logging. If you follow best practices for database design and tuning techniques for SQL operations, ...
https://dev.mysql.com/doc/refman/8.4/en/optimizing-queries-myisam.html
An update of the following form is very fast: UPDATE tbl_name SET count_col=count_col+1 WHERE key_col=constant; This is very important when you use MySQL storage engines such as MyISAM that has only table-level locking (multiple readers with single ... Some general tips for speeding up queries on MyISAM tables: To help MySQL better optimize queries, use ANALYZE TABLE or run myisamchk --analyze on a table after it has been loaded with ...
https://dev.mysql.com/doc/refman/8.4/en/other-vendor-data-types.html
To facilitate the use of code written for SQL implementations from other vendors, MySQL maps data types as shown in the following table. These mappings make it easier to import table definitions from other database systems into MySQL. If you create ...
https://dev.mysql.com/doc/refman/8.4/en/outer-join-optimization.html
MySQL implements an A LEFT JOIN B join_specification as follows: Table B is set to depend on table A and all tables on which A depends. Table A is set to depend on all tables (except B) that are used in the LEFT JOIN condition. The LEFT JOIN ...
https://dev.mysql.com/doc/refman/8.4/en/partitioning-columns.html
COLUMNS partitioning enables the use of multiple columns in partitioning keys. The next two sections discuss COLUMNS partitioning, which are variants on RANGE and LIST partitioning. All of these columns are taken into account both for the purpose ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-accounts-table.html
The accounts table has these indexes: Primary key on (USER, HOST) . The accounts table contains a row for each account that has connected to the MySQL server. For each account, the table counts the current and total number of connections. To set ...