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https://dev.mysql.com/doc/refman/5.7/en/sys-statements-with-full-table-scans.html
db The default database for the statement, or NULL if there is none. total_latency The total wait time of timed statement events for the statement. rows_examined The total number of rows read from the storage engine for the table. rows_examined_avg ... These views display normalized statements that have done full table ...
https://dev.mysql.com/doc/refman/5.7/en/gis-class-geometry.html
For example, in different coordinate systems, the distance between two objects may differ even when objects have the same coordinates, because the distance on the planar coordinate system and the distance on the geodetic system (coordinates on the ...It is a noninstantiable class but has a number of properties, described in the following list, that are common to all geometry values created from any of the Geometry ...
https://dev.mysql.com/doc/refman/5.7/en/information-schema-innodb-buffer-page-table.html
The INNODB_BUFFER_PAGE table provides information about each page in the InnoDB buffer pool. For related usage information and examples, see Section 14.16.5, “InnoDB INFORMATION_SCHEMA Buffer Pool Tables”. Do not query this table on a ...The ...
https://dev.mysql.com/doc/refman/5.7/en/information-schema-innodb-locks-table.html
The INNODB_LOCKS table provides information about each lock that an InnoDB transaction has requested but not yet acquired, and each lock that a transaction holds that is blocking another transaction. Although LOCK_ID currently contains TRX_ID, the ...Note This table is deprecated as of MySQL 5.7.14 and is removed in MySQL ...
https://dev.mysql.com/doc/refman/5.7/en/innodb-linux-native-aio.html
InnoDB uses the asynchronous I/O subsystem (native AIO) on Linux to perform read-ahead and write requests for data file pages. With synchronous I/O, query threads queue I/O requests, and InnoDB background threads retrieve the queued requests one at ...This behavior is controlled by the innodb_use_native_aio configuration option, which applies to Linux systems only and is enabled by ...
https://dev.mysql.com/doc/refman/5.7/en/innodb-online-ddl.html
The online DDL feature provides support for in-place table alterations and concurrent DML. Benefits of this feature include: Improved responsiveness and availability in busy production environments, where making a table unavailable for minutes or ...Less disk space usage and I/O overhead than the table-copy ...
https://dev.mysql.com/doc/refman/5.7/en/innodb-performance-compression-oltp.html
Traditionally, the InnoDB compression feature was recommended primarily for read-only or read-mostly workloads, such as in a data warehouse configuration. The rise of SSD storage devices, which are fast but relatively small and expensive, makes ...
https://dev.mysql.com/doc/refman/5.7/en/insert-optimization.html
Ideally, you make a single connection, send the data for many new rows at once, and delay all index updates and consistency checking until the very end. See Section 8.5.5, “Bulk Data Loading for InnoDB Tables” for tips specific to InnoDB tables.
https://dev.mysql.com/doc/refman/5.7/en/is-null-optimization.html
MySQL can perform the same optimization on col_name IS NULL that it can use for col_name = constant_value. For example, MySQL can use indexes and ranges to search for NULL with IS NULL. This optimization does not occur in cases when the column ...
https://dev.mysql.com/doc/refman/5.7/en/replication-features-temptables.html
The discussion in the following paragraphs does not apply when binlog_format=ROW because, in that case, temporary tables are not replicated; this means that there are never any temporary tables on the replica to be lost in the event of an unplanned ...If you stop the replica server, the temporary tables needed by those updates are no longer available when the replica is ...