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https://dev.mysql.com/doc/refman/5.7/en/date-calculations.html
MySQL provides several functions that you can use to perform calculations on dates, for example, to calculate ages or extract parts of dates. To determine how many years old each of your pets is, use the TIMESTAMPDIFF() function. Its arguments are ...
https://dev.mysql.com/doc/refman/5.7/en/engine-condition-pushdown-optimization.html
This optimization improves the efficiency of direct comparisons between a nonindexed column and a constant. In such cases, the condition is “pushed down” to the storage engine for evaluation. This optimization can be used only by the NDB ...
https://dev.mysql.com/doc/refman/5.7/en/generated-column-index-optimizations.html
For example: CREATE TABLE t1 (f1 INT, gc INT AS (f1 + 1) STORED, INDEX (gc)); The generated column, gc, is defined as the expression f1 + 1. The column is also indexed and the optimizer can take that index into account during execution plan ...
https://dev.mysql.com/doc/refman/5.7/en/information-schema-files-table.html
The FILES table provides information about the files in which MySQL tablespace data is stored. In NDB Cluster, this table also provides information about the files in which NDB Cluster Disk Data tables are stored. For additional information ...
https://dev.mysql.com/doc/refman/5.7/en/information-schema-innodb-buffer-page-lru-table.html
The INNODB_BUFFER_PAGE_LRU table provides information about the pages in the InnoDB buffer pool; in particular, how they are ordered in the LRU list that determines which pages to evict from the buffer pool when it becomes full. The ...
https://dev.mysql.com/doc/refman/5.7/en/innodb-change-buffer.html
During this time, disk I/O is increased, which can cause a significant slowdown for disk-bound queries. To avoid impacting performance, reproduce the issue you want to investigate on a test instance and run your queries on the test instance. The ...
https://dev.mysql.com/doc/refman/5.7/en/innodb-locking-reads.html
Other transactions can update or delete the same rows you just queried. All locks set by LOCK IN SHARE MODE and FOR UPDATE queries are released when the transaction is committed or rolled back. If you query data and then insert or update related ...
https://dev.mysql.com/doc/refman/5.7/en/innodb-read-only-instance.html
You might use this technique to avoid bottlenecks that can occur with a heavily loaded MySQL instance, or you might use different configuration options for the various instances to tune each one for particular kinds of queries. See Section 8.5.3, ...
https://dev.mysql.com/doc/refman/5.7/en/json-utility-functions.html
This section documents utility functions that act on JSON values, or strings that can be parsed as JSON values. JSON_PRETTY() prints out a JSON value in a format that is easy to read. JSON_STORAGE_SIZE() shows the amount of storage space used by a ...
https://dev.mysql.com/doc/refman/5.7/en/migrating-from-year2.html
YEAR(2) column in existing tables remain as YEAR(2): Before MySQL 5.7.5, YEAR(2) is processed in queries as in older versions of MySQL. As of MySQL 5.7.5, YEAR(2) columns in queries produce warnings or errors. This section describes problems that ...