PDF (US Ltr)
- 35.1Mb
PDF (A4)
- 35.2Mb
Man Pages (TGZ)
- 256.3Kb
Man Pages (Zip)
- 361.2Kb
Info (Gzip)
- 3.4Mb
Info (Zip)
- 3.4Mb
Search Results
https://dev.mysql.com/doc/refman/5.7/en/outer-join-simplification.html
Table expressions in the FROM clause of a query are simplified in many cases. At the parser stage, queries with right outer join operations are converted to equivalent queries containing only left join operations. When the optimizer evaluates plans ...
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/performance-schema-events-statements-current-table.html
The table stores one row per thread showing the current status of the thread's most recent monitored statement event, so there is no system variable for configuring the table size. Of the tables that contain statement event rows, ...
https://dev.mysql.com/doc/refman/5.7/en/performance-schema-examples.html
The Performance Schema is a tool to help a DBA do performance tuning by taking real measurements instead of “wild guesses.” This section demonstrates some ways to use the Performance Schema for this purpose. The discussion here relies on the ...
https://dev.mysql.com/doc/refman/5.7/en/performance-schema-mutex-instances-table.html
The mutex_instances table lists all the mutexes seen by the Performance Schema while the server executes. A mutex is a synchronization mechanism used in the code to enforce that only one thread at a given time can have access to some common ...
https://dev.mysql.com/doc/refman/5.7/en/performance-schema-performance-timers-table.html
The rows that do not contain NULL indicate which timers you can use in setup_timers. For an explanation of how event timing occurs, see Section 25.4.1, “Performance Schema Event Timing”. Note As of MySQL 5.7.21, the Performance Schema ...
https://dev.mysql.com/doc/refman/5.7/en/performance-schema-status-monitoring.html
Names for these variables have several forms: Performance_schema_xxx_classes_lost indicates how many instruments of type xxx could not be loaded. Performance_schema_xxx_instances_lost indicates how many instances of object type xxx could not be ...
https://dev.mysql.com/doc/refman/5.7/en/performance-schema-status-variable-tables.html
Note The value of the show_compatibility_56 system variable affects the information available from the tables described here. For details, see the description of that variable in Section 5.1.7, “Server System Variables”. The MySQL server ...
https://dev.mysql.com/doc/refman/5.7/en/point-in-time-recovery-positions.html
The last section, Section 7.5.1, “Point-in-Time Recovery Using Binary Log”, explains the general idea of using the binary log to perform a point-in-time-recovery. As an example, suppose that around 13:00:00 on May 27, 2020, an SQL statement was ...
https://dev.mysql.com/doc/refman/5.7/en/query-cache.html
Note The query cache is deprecated as of MySQL 5.7.20, and is removed in MySQL 8.0. The query cache stores the text of a SELECT statement together with the corresponding result that was sent to the client. If an identical statement is received ...