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https://dev.mysql.com/doc/refman/5.7/en/mysql-logging.html
Then use either of the following techniques to prevent it from being created again: Set the MYSQL_HISTFILE environment variable to /dev/null. Create .mysql_history as a symbolic link to /dev/null; this need be done only once: ln -s /dev/null ... The ...
https://dev.mysql.com/doc/refman/5.7/en/numeric-type-syntax.html
SERIAL is an alias for BIGINT UNSIGNED NOT NULL AUTO_INCREMENT UNIQUE. SERIAL DEFAULT VALUE in the definition of an integer column is an alias for NOT NULL AUTO_INCREMENT UNIQUE. SERIAL is an alias for BIGINT UNSIGNED NOT NULL AUTO_INCREMENT UNIQUE.
https://dev.mysql.com/doc/refman/5.7/en/optimizing-innodb-queries.html
If an indexed column cannot contain any NULL values, declare it as NOT NULL when you create the table. The optimizer can better determine which index is most effective to use for a query, when it knows whether each column contains NULL values. To ...
https://dev.mysql.com/doc/refman/5.7/en/order-by-optimization.html
If a query includes GROUP BY but you want to avoid the overhead of sorting the result, you can suppress sorting by specifying ORDER BY NULL. For example: INSERT INTO foo SELECT a, COUNT(*) FROM bar GROUP BY a ORDER BY NULL; The optimizer may still ... 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 ...
https://dev.mysql.com/doc/refman/5.7/en/partitioning-linear-hash.html
MySQL also supports linear hashing, which differs from regular hashing in that linear hashing utilizes a linear powers-of-two algorithm whereas regular hashing employs the modulus of the hashing function's value. We call this value V; it can be ...
https://dev.mysql.com/doc/refman/5.7/en/partitioning-overview.html
This section provides a conceptual overview of partitioning in MySQL 5.7. For information on partitioning restrictions and feature limitations, see Section 22.6, “Restrictions and Limitations on Partitioning”. The SQL standard does not provide ...
https://dev.mysql.com/doc/refman/5.7/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/5.7/en/performance-schema-replication-tables.html
At this time, there are no active replica threads, so the THREAD_ID columns are NULL and the SERVICE_STATE columns have a value of OFF. After STOP SLAVE, the THREAD_ID columns become NULL and the SERVICE_STATE columns for threads that no longer ...
https://dev.mysql.com/doc/refman/5.7/en/replication-options-binary-log.html
Prior to MySQL 5.7.2, this option caused any statements containing fully qualified table names not to be logged if there was no default database specified (that is, when SELECT DATABASE() returned NULL). Otherwise, if the table has a unique key all ... Startup Options Used with Binary Logging System Variables Used with Binary Logging You can use the mysqld options and system variables that are described in this section to affect the operation of the binary log as well as to control which statements are written to the binary ...
https://dev.mysql.com/doc/refman/5.7/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 ...