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https://dev.mysql.com/doc/refman/8.4/en/innodb-restrictions-limitations.html
mysql> CREATE TABLE t1 (c1 INT, db_row_id INT) ENGINE=INNODB; ERROR 1166 (42000): Incorrect column name 'db_row_id' SHOW TABLE STATUS does not provide accurate statistics for InnoDB tables except for the physical size reserved by the table. InnoDB ... This section describes restrictions and limitations of the InnoDB storage ...
https://dev.mysql.com/doc/refman/8.4/en/locking-functions.html
Returns 1 if the lock was obtained successfully, 0 if the attempt timed out (for example, because another client has previously locked the name), or NULL if an error occurred (such as running out of memory or the thread was killed with mysqladmin ...
https://dev.mysql.com/doc/refman/8.4/en/locking-issues.html
MySQL manages contention for table contents using locking: Internal locking is performed within the MySQL server itself to manage contention for table contents by multiple threads. External locking occurs when the server and other programs lock ...
https://dev.mysql.com/doc/refman/8.4/en/myisam-start.html
The following options to mysqld can be used to change the behavior of MyISAM tables. Note If you do this, you should not access MyISAM tables from another program (such as from another MySQL server or with myisamchk) when the tables are in use.
https://dev.mysql.com/doc/refman/8.4/en/no-matching-rows.html
Remove one table at a time from the query until it returns some rows. If you still cannot figure out what is wrong, create a minimal test that can be run with mysql test < query.sql that shows your problems. You can create a test file by dumping the ... If you have a complicated query that uses many tables but that returns no rows, you should use the following procedure to find out what is wrong: Test the query with EXPLAIN to check whether you can find something that is obviously ...
https://dev.mysql.com/doc/refman/8.4/en/optimization-indexes.html
Although it can be tempting to create an indexes for every possible column used in a query, unnecessary indexes waste space and waste time for MySQL to determine which indexes to use. The best way to improve the performance of SELECT operations is ...
https://dev.mysql.com/doc/refman/8.4/en/optimize-benchmarking.html
To measure performance, consider the following factors: Whether you are measuring the speed of a single operation on a quiet system, or how a set of operations (a “workload”) works over a period of time. Benchmarks are typically long-running ...
https://dev.mysql.com/doc/refman/8.4/en/outer-join-optimization.html
MySQL implements an A LEFT JOIN B join_specification as follows: Table B is set to depend on table A and all tables on which A depends. Table A is set to depend on all tables (except B) that are used in the LEFT JOIN condition. The LEFT JOIN ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-replication-group-members-table.html
UNREACHABLE: The failure detection process suspects that this member cannot be contacted, because the group messages have timed out. MEMBER_COMMUNICATION_STACK The communication stack used for the group, either the XCOM communication stack or the ...
https://dev.mysql.com/doc/refman/8.4/en/purge-binary-logs.html
PURGE BINARY LOGS { TO 'log_name' | BEFORE datetime_expr } The binary log is a set of files that contain information about data modifications made by the MySQL server. Examples: PURGE BINARY LOGS TO 'mysql-bin.010'; PURGE BINARY LOGS BEFORE ...If ...The log consists of a set of binary log files, plus an index file (see Section 7.4.4, “The Binary ...