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https://dev.mysql.com/doc/mysqld-version-reference/en/keywords.html
This section contains information on the keywords and reserved words within the server when creating and submitting queries to the system. For more information on reserved words and their impact on your queries, see Keywords and Reserved Words, in ...The following table shows all keywords and reserved words available in MySQL ...
https://dev.mysql.com/doc/mysql-em-plugin/en/myoem-metric-threads-activity-category.html
Slow Launch Threads (Delta) The number of threads that have taken more than slow_launch_time seconds to create. Too Many Concurrent Queries Running Too many active queries indicates there is a severe load on the server, and may be a sign of lock ...
https://dev.mysql.com/doc/refman/8.4/en/debugging-server.html
This command also provides some useful information even if you have not compiled MySQL for debugging! If the problem is that some tables are getting slower and slower you should try to optimize the table with OPTIMIZE TABLE or myisamchk. If you are ...
https://dev.mysql.com/doc/refman/8.4/en/error-log-event-fields.html
This ID indicates which part of the server produced the event, and is consistent with general query log and slow query log messages, which include the connection thread ID. Error events intended for the error log contain a set of fields, each of ...
https://dev.mysql.com/doc/refman/8.4/en/error-lost-connection.html
Sometimes the “during query” form happens when millions of rows are being sent as part of one or more queries. In this case, if your connect_timeout value is set to only a few seconds, you may be able to resolve the problem by increasing it to ...Usually it indicates network connectivity trouble and you should check the condition of your network if this error occurs ...
https://dev.mysql.com/doc/refman/8.4/en/insert-optimization.html
The size of the table slows down the insertion of indexes by log N, assuming B-tree indexes. To optimize insert speed, combine many small operations into a single large operation. Ideally, you make a single connection, send the data for many new ...
https://dev.mysql.com/doc/refman/8.4/en/keywords.html
Certain keywords, such as SELECT, DELETE, or BIGINT, are reserved and require special treatment for use as identifiers such as table and column names. This may also be true for the names of built-in functions. Some keywords which are otherwise ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-examples.html
To begin, you should have a repeatable use case where performance is deemed “too slow” and needs optimization, and you should enable all instrumentation (no pre-filtering at all). The Performance Schema is a tool to help a DBA do performance ...
https://dev.mysql.com/doc/relnotes/mysql/8.4/en/news-8-4-1.html
GROUP BY queries were at least twice as slow with the TempTable engine than the Memory engine. It was removed due to a critical issue that could stop the server from restarting following the creation of a very large number of tables (8001 or more).
https://dev.mysql.com/doc/connectors/en/connector-j-interceptors.html
In these kinds of interceptor classes, you might change or augment the processing done by certain kinds of statements, such as automatically checking for queried data in a memcached server, rewriting slow queries, logging information about statement ... An interceptor is a software design pattern that provides a transparent way to extend or modify some aspect of a program, similar to a user ...