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https://dev.mysql.com/doc/refman/8.0/en/order-by-optimization.html
This section describes when MySQL can use an index to satisfy an ORDER BY clause, the filesort operation used when an index cannot be used, and execution plan information available from the optimizer about ORDER BY. An ORDER BY with and without ...
https://dev.mysql.com/doc/refman/8.0/en/problems-connecting.html
If you change the grant tables directly (for example, by using INSERT, UPDATE, or DELETE statements) and your changes seem to be ignored, remember that you must execute a FLUSH PRIVILEGES statement or a mysqladmin flush-privileges command to cause ...If the server was started with the bind_address system variable set to 127.0.0.1, it listens for TCP/IP connections only locally on the loopback interface and does not accept remote ...
https://dev.mysql.com/doc/refman/8.0/en/where-optimization.html
The examples use SELECT statements, but the same optimizations apply for WHERE clauses in DELETE and UPDATE statements. Because MySQL does similar optimizations automatically, you can often avoid this work, and leave the query in a more ... This ...
https://dev.mysql.com/doc/refman/8.0/en/resource-groups.html
Currently, CPU time is a manageable resource, represented by the concept of “virtual CPU” as a term that includes CPU cores, hyperthreads, hardware threads, and so forth. These attributes are defined at resource group creation time and cannot be ... MySQL supports creation and management of resource groups, and permits assigning threads running within the server to particular groups so that threads execute according to the resources available to the ...
https://dev.mysql.com/doc/refman/8.0/en/binary-installation.html
These include generic binary distributions in the form of compressed tar files (files with a .tar.xz extension) for a number of platforms, and binaries in platform-specific package formats for selected platforms. MySQL compressed tar file binary ...
https://dev.mysql.com/doc/refman/8.0/en/innodb-locking.html
For example, SELECT c1 FROM t WHERE c1 BETWEEN 10 and 20 FOR UPDATE; prevents other transactions from inserting a value of 15 into column t.c1, whether or not there was already any such value in the column, because the gaps between all existing ...A ...
https://dev.mysql.com/doc/refman/8.0/en/join.html
MySQL supports the following JOIN syntax for the table_references part of SELECT statements and multiple-table DELETE and UPDATE statements: table_references: escaped_table_reference [, escaped_table_reference] ... This option follows the name of ...index_hint: { USE {INDEX|KEY} [FOR {JOIN|ORDER BY|GROUP BY}] ([index_list]) | {IGNORE|FORCE} {INDEX|KEY} [FOR {JOIN|ORDER BY|GROUP BY}] (index_list) } index_list: index_name [, index_name] ...
https://dev.mysql.com/doc/refman/8.0/en/spatial-operator-functions.html
See that section for descriptions of these functions: ST_Envelope(g) ST_StartPoint(ls) ST_EndPoint(ls) ST_PointN(ls, N) ST_ExteriorRing(poly) ST_InteriorRingN(poly, N) ST_GeometryN(gc, N) Unless otherwise specified, functions in this section handle ... OpenGIS proposes a number of functions that can produce ...
https://dev.mysql.com/doc/refman/8.0/en/switchable-optimizations.html
This variable has global and session values and can be changed at runtime. (Depending on the nullability of the derived table, this can sometimes be simplified further to an inner join.) This can be done for a subquery which meets the following ...
https://dev.mysql.com/doc/refman/8.0/en/create-event.html
It specifies that the event executes one time only at the date and time given by timestamp, which must include both the date and time, or must be an expression that resolves to a datetime value. You may use CURRENT_TIMESTAMP to specify the current ...This is an example of a minimal CREATE EVENT statement: CREATE EVENT myevent ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 1 HOUR DO UPDATE myschema.mytable SET mycol = mycol + 1; The previous statement creates an event named ...