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https://dev.mysql.com/doc/refman/8.4/en/partitioning-overview.html
This section provides a conceptual overview of partitioning in MySQL 8.4. For information on partitioning restrictions and feature limitations, see Section 26.6, “Restrictions and Limitations on Partitioning”. The SQL standard does not provide ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-prepared-statements-instances-table.html
OWNER_OBJECT_TYPE, OWNER_OBJECT_SCHEMA, OWNER_OBJECT_NAME For a prepared statement created by a client session, these columns are NULL. These columns can be used to find stored programs that leak prepared statements: SELECT OWNER_OBJECT_TYPE, ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-replication-tables.html
At this time, there are no active replication threads, so the THREAD_ID columns are NULL and the SERVICE_STATE columns have a value of OFF. After STOP REPLICA, the THREAD_ID columns become NULL and the SERVICE_STATE columns for threads that no ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-system-variables.html
If an error occurs that is not instrumented, information for the occurrence is aggregated to the NULL row in each summary table; that is, to the row with ERROR_NUMBER=0, ERROR_NAME=NULL, and SQLSTATE=NULL. The Performance Schema automatically sizes ...
https://dev.mysql.com/doc/refman/8.4/en/replication-administration-status.html
row *************************** Id: 10 User: root Host: replica1:58371 db: NULL Command: Binlog Dump Time: 777 State: Has sent all binlog to slave; waiting for binlog to be updated Info: NULL Because it is the replica that drives the replication ...
https://dev.mysql.com/doc/refman/8.4/en/replication-features-row-searches.html
A unique index where every column in the index has a NOT NULL attribute. If the algorithm is able to select a primary key or a unique index where every column in the index has a NOT NULL attribute, it uses this index to iterate over the rows in the ... When a replica using row-based replication format applies an UPDATE or DELETE operation, it must search the relevant table for the matching ...
https://dev.mysql.com/doc/refman/8.4/en/replication-functions-synchronization.html
The function returns NULL if the replication SQL thread is not started, the replica's source information is not initialized, the arguments are incorrect, or an error occurs. If the replication SQL thread stops while SOURCE_POS_WAIT() is waiting, the ... The functions listed in this section are used for controlling position-based synchronization of source and replica servers in MySQL ...
https://dev.mysql.com/doc/refman/8.4/en/row-constructor-optimization.html
row *************************** id: 1 select_type: SIMPLE table: t1 partitions: NULL type: ref possible_keys: PRIMARY key: PRIMARY key_len: 4 ref: const rows: 3 filtered: 100.00 Extra: Using where In such cases, rewriting the row constructor ...For ...
https://dev.mysql.com/doc/refman/8.4/en/set.html
For example, a column specified as SET('one', 'two') NOT NULL can have any of these values: '' 'one' 'two' 'one,two' A SET column can have a maximum of 64 distinct members. A SET is a string object that can have zero or more values, each of which ...
https://dev.mysql.com/doc/refman/8.4/en/spatial-geohash-functions.html
Unless otherwise specified, functions in this section handle their geometry arguments as follows: If any argument is NULL, the return value is NULL. Geohash is a system for encoding latitude and longitude coordinates of arbitrary precision into a ...