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https://dev.mysql.com/doc/refman/8.4/en/optimize-character.html
The GROUP BY and ORDER BY clauses can generate temporary tables, and these temporary tables can use the MEMORY storage engine if the original table does not contain any BLOB columns. If a table contains string columns such as name and address, but ... For character and string columns, follow these guidelines: Use binary collation order for fast comparison and sort operations, when you do not need language-specific collation ...
https://dev.mysql.com/doc/refman/8.4/en/partitioning-columns-list.html
See Section 15.1.20, “CREATE TABLE Statement”, for additional information about PARTITION BY LIST COLUMNS() syntax. This is a variant of LIST partitioning that enables the use of multiple columns as partition keys, and for columns of data types ...
https://dev.mysql.com/doc/refman/8.4/en/precision-math-examples.html
Consider these statements: mysql> CREATE TABLE t (i INT, d DECIMAL, f FLOAT); mysql> INSERT INTO t VALUES(1,1,1); mysql> CREATE TABLE y SELECT AVG(i), AVG(d), AVG(f) FROM t; The result is a double only for the floating-point argument. This section ...
https://dev.mysql.com/doc/refman/8.4/en/replication-howto-additionalslaves.html
You can list the events on a server using the SHOW statement or the Information Schema EVENTS table. For example, the InnoDB system tablespace, undo tablespace, and redo log might be stored in an alternative location. InnoDB tablespace files and ...
https://dev.mysql.com/doc/refman/8.4/en/replication-solutions-partitioning.html
Figure 19.2 Replicating Databases to Separate Replicas You can achieve this separation by configuring the source and replicas as normal, and then limiting the binary log statements that each replica processes by using the --replicate-wild-do-table ... There may be situations where you have a single source server and want to replicate different databases to different ...
https://dev.mysql.com/doc/refman/8.4/en/replication-solutions-unexpected-replica-halt.html
This repository is created by default as an InnoDB table named mysql.slave_relay_log_info. DML transactions and also atomic DDL update the replication positions in the replica's applier metadata repository in the mysql.slave_relay_log_info table ...
https://dev.mysql.com/doc/refman/8.4/en/show.html
SHOW has many forms that provide information about databases, tables, columns, or status information about the server. In addition, you can work in SQL with results from queries on tables in the INFORMATION_SCHEMA database, which you cannot easily ...The pattern is useful for restricting statement output to matching ...
https://dev.mysql.com/doc/refman/8.4/en/subquery-errors.html
All of the errors described in this section also apply when using TABLE in subqueries. Incorrect number of rows from subquery: ERROR 1242 (ER_SUBSELECT_NO_1_ROW) SQLSTATE = 21000 Message = "Subquery returns more than 1 row" This error occurs for ...
https://dev.mysql.com/doc/refman/8.4/en/user-resources.html
Only statements that modify databases or tables count against the update limit. An “account” in this context corresponds to a row in the mysql.user system table. That is, a connection is assessed against the User and Host values in the user ...
https://dev.mysql.com/doc/mysql-enterprise-backup/8.4/en/index.html
Abstract This is the user manual for MySQL Enterprise Backup, a commercially licensed backup utility for MySQL databases. It explains the different kinds of backup and restore that can be performed with MySQL Enterprise Backup, and describes the ...