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https://dev.mysql.com/doc/refman/8.4/en/performance-schema-table-wait-summary-tables.html
These columns have the same meaning as in the events_waits_current table. As indicated in the column descriptions, some columns are more general and have values that are the same as the sum of the values of more fine-grained columns. These columns ... The following sections describe the table I/O and lock wait summary tables: table_io_waits_summary_by_index_usage: Table I/O waits per index table_io_waits_summary_by_table: Table I/O waits per table table_lock_waits_summary_by_table: Table lock waits per table 29.12.20.8.1 The table_io_waits_summary_by_table Table The table_io_waits_summary_by_table table aggregates all table I/O wait events, as generated by the wait/io/table/sql/handler ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-threads-table.html
Monitoring occurs only for those thread events produced from instruments that have the ENABLED column set to YES in the setup_instruments table. Logging occurs only for those thread events produced from instruments that have the ENABLED column set ... The threads table contains a row for each server ...
https://dev.mysql.com/doc/refman/8.4/en/problems-with-float.html
If columns d1 and d2 had been defined as DECIMAL rather than DOUBLE, the result of the SELECT query would have contained only one row—the last one shown above. Floating-point numbers sometimes cause confusion because they are approximate and not ...
https://dev.mysql.com/doc/refman/8.4/en/replication-binlog-encryption-key-rotation.html
You can rotate the binary log master key on a regular basis to comply with your organization's security policy, and also if you suspect that the current or any of the previous binary log master keys might have been compromised. Then investigate the ... When binary log encryption is enabled, you can rotate the binary log master key at any time while the server is running by issuing ALTER INSTANCE ROTATE BINLOG MASTER ...
https://dev.mysql.com/doc/refman/8.4/en/replication-channels.html
This section describes how channels can be used in a replication topology, and the impact they have on single-source replication. Each replication channel must have a unique (nonempty) name, as explained in Section 19.2.2.4, “Replication Channel ... In MySQL multi-source replication, a replica opens multiple replication channels, one for each source ...
https://dev.mysql.com/doc/refman/8.4/en/replication-features-errors.html
Note If a temporary error is recorded in the replica's error log, you do not necessarily have to take any action suggested in the quoted error message. For nontransactional storage engines such as MyISAM, it is possible to have a statement that only ... If a statement produces the same error (identical error code) on both the source and the replica, the error is logged, but replication ...
https://dev.mysql.com/doc/refman/8.4/en/replication-features-triggers.html
If you want triggers to execute on both the source and the replica, perhaps because you have different triggers on the source and replica, you must use statement-based replication. (Bug #45677) A trigger can have triggers for different combinations ... With statement-based replication, triggers executed on the source also execute on the ...
https://dev.mysql.com/doc/refman/8.4/en/replication-gtids-failover.html
The source's global gtid_purged variable contains the set of all transactions that have been purged from the source's binary log. When restoring a replica in a GTID based replication setup that has encountered an error, injecting an empty ... There ...
https://dev.mysql.com/doc/refman/8.4/en/replication-mode-change-online-disable-gtids.html
However, if you have the possibility to take the servers offline when disabling GTIDs mode that process is easier. Before starting, all servers must meet the following conditions: All servers have gtid_mode set to ON. See Section 19.1.4.4, ... This ...
https://dev.mysql.com/doc/refman/8.4/en/replication-options-reference.html
gtid_executed_compression_period: Compress gtid_executed table each time this many transactions have occurred. gtid_purged: Set of all GTIDs that have been purged from binary log. The following two sections provide basic information about the MySQL ...