https://dev.mysql.com/replication-options-slave.html
On the master and each slave, you must set the server_id system variable to establish a unique replication ID in the range from 1 to 232 − 1. “Unique” means that each ID must be different from every other ID in use by any other replication ...
https://dev.mysql.com/st-spatial-reference-systems-table.html
The ST_SPATIAL_REFERENCE_SYSTEMS table provides information about available spatial reference systems for spatial data. Entries in the ST_SPATIAL_REFERENCE_SYSTEMS table are based on the European Petroleum Survey Group (EPSG) data set, except for ...
https://dev.mysql.com/table-constraints-table.html
The value can be UNIQUE, PRIMARY KEY, FOREIGN KEY, or (as of MySQL 8.0.16) CHECK. The UNIQUE and PRIMARY KEY information is about the same as what you get from the Key_name column in the output from SHOW INDEX when the Non_unique column is 0. The ...
https://dev.mysql.com/threads-table.html
The threads table has these columns: THREAD_ID A unique thread identifier. For background threads (threads not associated with a user connection), PROCESSLIST_ID is NULL, so the values are not unique. The threads table contains a row for each ...
https://dev.mysql.com/tp-thread-group-state-table.html
That is, these two queries are equivalent: SELECT TP_GROUP_ID, MAX_THREAD_IDS_IN_GROUP FROM tp_thread_group_state; SELECT TP_GROUP_ID, MAX(TP_THREAD_NUMBER) FROM tp_thread_state GROUP BY TP_GROUP_ID; The tp_thread_group_state table has these ...
https://dev.mysql.com/tp-thread-group-stats-table.html
The tp_thread_group_stats table has these indexes: Unique index on (TP_GROUP_ID) TRUNCATE TABLE is not permitted for the tp_thread_group_stats table. Note The Performance Schema table described here is available as of MySQL 8.0.14. Prior to MySQL ...
https://dev.mysql.com/tp-thread-state-table.html
TP_GROUP_ID and TP_THREAD_NUMBER together provide a unique key within the table. Note The Performance Schema table described here is available as of MySQL 8.0.14. Prior to MySQL 8.0.14, use the corresponding INFORMATION_SCHEMA table instead; see ...
https://dev.mysql.com/update.html
Rows for which duplicate-key conflicts occur on a unique key value are not updated. Suppose that a table t contains a column id that has a unique index. UPDATE is a DML statement that modifies rows in a table. An UPDATE statement can start with a ...
https://dev.mysql.com/upgrading-from-previous-series.html
Because constraint names must be unique per schema (database), the change caused errors due to foreign key index names that were not unique per schema. Before upgrading to MySQL 8.0, review the changes described in this section to identify those ...
https://dev.mysql.com/with.html
To make the statement legal, define the CTEs with unique names: WITH cte1 AS (...), cte2 AS (...) SELECT ... A common table expression (CTE) is a named temporary result set that exists within the scope of a single statement and that can be referred ...
