https://dev.mysql.com/optimizer-statistics.html
Here is a sample histogram object: { "buckets": [ [ 1, 0.3333333333333333 ], [ 2, 0.6666666666666666 ], [ 3, 1 ] ], "null-values": 0, "last-updated": "2017-03-24 13:32:40.000000", "sampling-rate": 1, "histogram-type": "singleton", ... The ...
https://dev.mysql.com/partitioning-hash.html
Partitioning by HASH is used primarily to ensure an even distribution of data among a predetermined number of partitions. To partition a table using HASH partitioning, it is necessary to append to the CREATE TABLE statement a PARTITION BY HASH ...
https://dev.mysql.com/performance-schema-functions.html
It may be used as a shortcut for invoking the sys schema ps_thread_id() function with an argument of NULL or CONNECTION_ID(). PS_THREAD_ID(connection_id) Given a connection ID, returns a BIGINT UNSIGNED value representing the Performance Schema ...
https://dev.mysql.com/replace.html
REPLACE [LOW_PRIORITY | DELAYED] [INTO] tbl_name [PARTITION (partition_name [, partition_name] ...)] [(col_name [, col_name] ...)] {VALUES | VALUE} (value_list) [, (value_list)] ... REPLACE [LOW_PRIORITY | DELAYED] [INTO] tbl_name [PARTITION ...
https://dev.mysql.com/replication-implementation-details.html
row *************************** Id: 2 User: root Host: localhost:32931 db: NULL Command: Binlog Dump Time: 94 State: Has sent all binlog to slave; waiting for binlog to be updated Info: NULL Here, thread 2 is a Binlog Dump replication thread that ...
https://dev.mysql.com/scalar-subqueries.html
A scalar subquery is a simple operand, and you can use it almost anywhere a single column value or literal is legal, and you can expect it to have those characteristics that all operands have: a data type, a length, an indication that it can be ...
https://dev.mysql.com/spatial-geojson-functions.html
This section describes functions for converting between GeoJSON documents and spatial values. Feature and FeatureCollection objects are not supported, except that geometry objects are extracted from them. MySQL also supports a native JSON data type ...
https://dev.mysql.com/statement-summary-tables.html
If no row has the statement digest value for the statement that just completed, and the table is full, the statistics for the statement that just completed are added to a special “catch-all” row with DIGEST = NULL, which is created if necessary.
https://dev.mysql.com/statistics-table.html
This can have values A (ascending), D (descending), or NULL (not sorted). That is, the number of indexed characters if the column is only partly indexed, NULL if the entire column is indexed. NULLABLE Contains YES if the column may contain NULL ...
https://dev.mysql.com/sys-sys-get-config.html
Given a configuration option name, returns the option value from the sys_config table, or the provided default value (which may be NULL) if the option does not exist in the table. If sys_get_config() returns the default value and that value is ...
