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https://dev.mysql.com/doc/refman/8.4/en/performance-schema-table-descriptions.html
Tables in the performance_schema database can be grouped as follows: Setup tables. These tables contain information aggregated over groups of events, including those that have been discarded from the history tables. These do not fall into any of ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-threads-table.html
row *************************** THREAD_ID: 1 NAME: thread/sql/main TYPE: BACKGROUND PROCESSLIST_ID: NULL PROCESSLIST_USER: NULL PROCESSLIST_HOST: NULL PROCESSLIST_DB: mysql PROCESSLIST_COMMAND: NULL PROCESSLIST_TIME: 418094 PROCESSLIST_STATE: NULL ... The threads table contains a row for each server ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-tp-connections-table.html
TP_GROUP_ID The index of the thread group in the global array. CONNECT_HANDLER_INDEX The index of the connection handler thread in the group which processed the connection request; a higher number means the connection load has triggered the creation ... The tp_connections table contains one row per connection managed by the Thread Pool ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-tp-thread-state-table.html
The tp_thread_state table has these columns: TP_GROUP_ID The thread group ID. TP_GROUP_ID and TP_THREAD_NUMBER together provide a unique key within the table. The xxx_WAIT columns of the tp_thread_group_stats table accumulate counts for each wait ...
https://dev.mysql.com/doc/refman/8.4/en/problems-with-float.html
Floating-point numbers sometimes cause confusion because they are approximate and not stored as exact values. A floating-point value as written in an SQL statement may not be the same as the value represented internally. Attempts to treat ...
https://dev.mysql.com/doc/refman/8.4/en/programs-development.html
This section describes some utilities that you may find useful when developing MySQL programs. In shell scripts, you can use the my_print_defaults program to parse option files and see what options would be used by a given program. This works well ...
https://dev.mysql.com/doc/refman/8.4/en/range-optimization.html
The optimizer can perform multiple range scans, one for each value of f1, using a method called Skip Scan that is similar to Loose Index Scan (see Section 10.2.1.17, “GROUP BY Optimization”): Skip between distinct values of the first index part, ... The range access method uses a single index to retrieve a subset of table rows that are contained within one or several index value ...
https://dev.mysql.com/doc/refman/8.4/en/replication-rules.html
Note that replication filters cannot be used on Group Replication-specific channels on a MySQL server instance that is configured for Group Replication, because filtering transactions on some servers would make the group unable to reach agreement on ... If a replication source server does not write a statement to its binary log, the statement is not ...
https://dev.mysql.com/doc/refman/8.4/en/replication-semisync.html
If your goal is to implement a fault-tolerant replication topology where all the servers receive the same transactions in the same order, and a server that crashes can rejoin the group and be brought up to date automatically, you can use Group ...
https://dev.mysql.com/doc/refman/8.4/en/server-status-variables.html
If there is no pending resize down operation, Innodb_redo_log_capacity_resized should be equal to the innodb_redo_log_capacity setting if it's used, or it's ((innodb_log_files_in_group * innodb_log_file_size)) if those are used instead. On some ...