Search Results
https://dev.mysql.com/doc/refman/8.4/en/estimating-performance.html
In MySQL, an index block is usually 1,024 bytes and the data pointer is usually four bytes. As long as everything is cached by the OS or the MySQL server, things become only marginally slower as the table gets bigger. In most cases, you can ...
https://dev.mysql.com/doc/refman/8.4/en/events-syntax.html
MySQL provides several SQL statements for working with scheduled events: New events are defined using the CREATE EVENT statement. The definition of an existing event can be changed by means of the ALTER EVENT statement. When a scheduled event is no ...
https://dev.mysql.com/doc/refman/8.4/en/explain-extended.html
Here is an example of extended EXPLAIN output: mysql> EXPLAIN SELECT t1.a, t1.a IN (SELECT t2.a FROM t2) FROM t1\G *************************** 1. row *************************** id: 2 select_type: SUBQUERY table: t2 type: index possible_keys: a key: ... The EXPLAIN statement produces extra (“extended”) information that is not part of EXPLAIN output but can be viewed by issuing a SHOW WARNINGS statement following ...
https://dev.mysql.com/doc/refman/8.4/en/flow-control-statements.html
MySQL supports the IF, CASE, ITERATE, LEAVE LOOP, WHILE, and REPEAT constructs for flow control within stored programs. Many of these constructs contain other statements, as indicated by the grammar specifications in the following sections. For ...
https://dev.mysql.com/doc/refman/8.4/en/full-table.html
The effective maximum table size for MySQL databases is usually determined by operating system constraints on file sizes, not by MySQL internal limits. If a table-full error occurs, it may be that the disk is full or that the table has reached its ...
https://dev.mysql.com/doc/refman/8.4/en/geometry-well-formedness-validity.html
For geometry values, MySQL distinguishes between the concepts of syntactically well-formed and geometrically valid. Due to the computational expense, MySQL does not check explicitly for geometric validity. Spatial import functions that parse WKT or ...
https://dev.mysql.com/doc/refman/8.4/en/gis-wkb-functions.html
Prior to MySQL 8.4, these functions also accepted geometry objects as returned by the functions in Section 14.16.5, “MySQL-Specific Functions That Create Geometry Values”. These functions take as arguments a BLOB containing a Well-Known Binary ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-compatibility-communication.html
A replication group uses a Group Replication communication protocol version that differs from the MySQL Server version of the members. To check the group's communication protocol version, issue the following statement on any member: SELECT ...For ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-compatibility-upgrade.html
The primary cannot remain as the primary unless it is running the lowest MySQL Server version in the group. Note group_replication_allow_local_lower_version_join is deprecated and subject to removal in a future version of MySQL. During an online ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-distributed-recovery-fault.html
For state transfer from the binary log, the joiner selects a donor that is running a lower or equal patch version of MySQL Server compared to itself. Because this method of state transfer uses the existing MySQL replication framework, it is possible ... Group Replication's distributed recovery process has a number of built-in measures to ensure fault tolerance in the event of any problems during the ...