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https://dev.mysql.com/doc/refman/8.0/en/bnl-bka-optimization.html
When BKA is used, the value of join_buffer_size defines how large the batch of keys is in each request to the storage engine. If B2 is a regular join buffer, each row r put into B2 is composed of the columns of a row r1 from B1 and the interesting ... In MySQL, a Batched Key Access (BKA) Join algorithm is available that uses both index access to the joined table and a join ...
https://dev.mysql.com/doc/refman/8.0/en/with.html
A CTE that produces many rows may require an internal temporary table large enough to be converted from in-memory to on-disk format and may suffer a performance penalty. -- return additional row sets The first SELECT produces the initial row or rows ... 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 to later within that statement, possibly multiple ...
https://dev.mysql.com/doc/refman/8.0/en/mysql-cluster-programs-ndb-select-count.html
ndb_select_count prints the number of rows in one or more NDB tables. You can obtain row counts from multiple tables in the same database by listing the table names separated by spaces when invoking this command, as shown under Sample Output. With ...
https://dev.mysql.com/doc/refman/8.0/en/deleting-from-related-tables.html
If the total length of the DELETE statement for related_table is more than the default value of the max_allowed_packet system variable, you should split it into smaller parts and execute multiple DELETE statements. You probably get the fastest ...
https://dev.mysql.com/doc/refman/8.0/en/mysql-command-options.html
--max-join-size=value Command-Line Format --max-join-size=value Type Numeric Default Value 1000000 The automatic limit for rows in a join when using --safe-updates. --auto-vertical-output Command-Line Format --auto-vertical-output Cause result sets ... mysql supports the following options, which can be specified on the command line or in the [mysql] and [client] groups of an option ...
https://dev.mysql.com/doc/refman/8.0/en/fulltext-natural-language.html
This filtering technique is more suitable for large data sets, where you might not want the result set to return every second row from a 1GB table, than for small data sets where it might cause poor results for popular terms. For each row in the ...
https://dev.mysql.com/doc/refman/8.0/en/audit-log-reference.html
Audit_log_event_max_drop_size The size of the largest dropped event in performance logging mode. If audit_log_rotate_on_size is 0, automatic audit log file rotation is disabled and rotation occurs only when performed manually. It controls pruning ...
https://dev.mysql.com/doc/refman/8.0/en/communication-errors.html
Other reasons for problems with aborted connections or aborted clients: The max_allowed_packet variable value is too small or queries require more memory than you have allocated for mysqld. If connection problems occur such as communication errors ...
https://dev.mysql.com/doc/refman/8.0/en/mysql-cluster-ndb-transporter-errors.html
This section lists error codes, names, and messages that are written to the cluster log in the event of transporter errors. 0x00 TE_NO_ERROR No error 0x01 TE_ERROR_CLOSING_SOCKET Error found during closing of socket 0x02 ...
https://dev.mysql.com/doc/refman/8.0/en/optimizing-innodb-queries.html
Do not specify too many or too long columns in the primary key, because these column values are duplicated in each secondary index. If you have many queries for the same table, testing different combinations of columns, try to create a small number ... To tune queries for InnoDB tables, create an appropriate set of indexes on each ...