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https://dev.mysql.com/doc/refman/8.4/en/index-merge-optimization.html
In this case, the key column contains a list of indexes used, and key_len contains a list of the longest key parts for those indexes. AND key_partN = constN Any range condition over the primary key of an InnoDB table. Here is an example of such a ...
https://dev.mysql.com/doc/refman/8.4/en/information-functions.html
The conditions for use of SQL_CALC_FOUND_ROWS with UNION are: The SQL_CALC_FOUND_ROWS keyword must appear in the first SELECT of the UNION. ON DUPLICATE KEY UPDATE statements, the affected-rows value per row is 1 if the row is inserted as a new row, ...It may be used to time how quickly MySQL processes the ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-compression-internals.html
Each row in the index node contains the values of the (user-specified or system-generated) primary key and all the other columns of the table. Secondary indexes in InnoDB tables are also B-trees, containing pairs of values: the index key and a ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-limits.html
The index key prefix length limit is 3072 bytes for InnoDB tables that use DYNAMIC or COMPRESSED row format. The index key prefix length limit is 767 bytes for InnoDB tables that use the REDUNDANT or COMPACT row format. Attempting to use an index ...
https://dev.mysql.com/doc/refman/8.4/en/json-modification-functions.html
JSON_MERGE_PATCH(json_doc, json_doc[, json_doc] ...) Performs an RFC 7396 compliant merge of two or more JSON documents and returns the merged result, without preserving members having duplicate keys. If both arguments are objects, the result of the ... The functions in this section modify JSON values and return the ...
https://dev.mysql.com/doc/refman/8.4/en/midpoint-insertion.html
By default, the key cache management system uses a simple LRU strategy for choosing key cache blocks to be evicted, but it also supports a more sophisticated method called the midpoint insertion strategy. The division point between two parts is not ...When using the midpoint insertion strategy, the LRU chain is divided into two parts: a hot sublist and a warm ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-replication-connection-configuration-table.html
(CHANGE REPLICATION SOURCE TO option: SOURCE_AUTO_POSITION) SSL_ALLOWED, SSL_CA_FILE, SSL_CA_PATH, SSL_CERTIFICATE, SSL_CIPHER, SSL_KEY, SSL_VERIFY_SERVER_CERTIFICATE, SSL_CRL_FILE, SSL_CRL_PATH These columns show the SSL parameters used by the ...
https://dev.mysql.com/doc/refman/8.4/en/pluggable-authentication-system-variables.html
If this variable is not set, the default is mysql.keytab in the data directory. The file must exist and contain a valid key for the service principal name (SPN) or authentication of clients will fail. (The SPN and same key also must be created in ...
MySQL 8.4 Reference Manual :: 19.2.1.3 Determination of Safe and Unsafe Statements in Binary Logging
https://dev.mysql.com/doc/refman/8.4/en/replication-rbr-safe-unsafe.html
In addition, an INSERT into a table that has a composite primary key containing an AUTO_INCREMENT column that is not the first column of this composite key is unsafe. ON DUPLICATE KEY UPDATE statements on tables with multiple primary or unique keys.
https://dev.mysql.com/doc/refman/8.4/en/tracing-example.html
row *************************** QUERY: SELECT SUM(alias2.col_varchar_nokey) AS c1, alias2.pk AS c2 FROM t1 AS alias1 STRAIGHT_JOIN t2 AS alias2 ON alias2.pk = alias1.col_int_key WHERE alias1.pk GROUP BY c2 ORDER BY alias1.col_int_key, alias2.pk This ...Now we can examine the trace, whose first column (QUERY), containing the original statement to be traced, is shown here: SELECT * FROM INFORMATION_SCHEMA.OPTIMIZER_TRACE\G ...