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https://dev.mysql.com/doc/refman/8.4/en/sys-schema-unused-indexes.html
These views display indexes for which there are no events, which indicates that they are not being used. Otherwise, presence of an index in this view may not be meaningful. This view is most useful when the server has been up and processing long ...
https://dev.mysql.com/doc/internals/en/implementing-index-read-last-method.html
The [custom-engine.html#custom-engine-api-reference-index_read_last index_read_last()] method works like [custom-engine.html#custom-engine-index-read index_read()] but finds the last row with the current key value or prefix: int ...
https://dev.mysql.com/doc/internals/en/implementing-index-first-method.html
The [custom-engine.html#custom-engine-api-reference-index_first index_first()] method is used for index scanning: int ha_foo::index_first(byte * buf) The *buf parameter is populated with the row that corresponds to the first key value in the index.
https://dev.mysql.com/doc/internals/en/implementing-index-last-method.html
The [custom-engine.html#custom-engine-api-reference-index_last index_last()] method is used for reverse index scanning: int ha_foo::index_last(byte * buf) The *buf parameter is populated with the row that corresponds to the last key value in the ...
https://dev.mysql.com/doc/internals/en/index-end.html
Purpose Indicates end of index scan, clean up any resources used. Synopsis virtual int index_end ( ); ; Description This is the index_end method. Generally it is used as a counterpart to the index_init method, cleaning up any resources allocated for ...
https://dev.mysql.com/doc/internals/en/index-init.html
Purpose Signals the storage engine that an index scan is about to occur. Synopsis virtual int index_init ( idx, sorted); uint idx ; bool sorted ; Description This is the index_init method. This method is called before an index scan, allowing the ...
https://dev.mysql.com/doc/mysql-monitor/8.0/en/mem-features-qrti.html
You can then click on the query to get more information, such as the maximum and average query times, the average number of rows examined, the average lock wait time, examine a sample query, look at an example EXPLAIN plan, see if full table scans ...It is a "quality of service" measurement for each query, and uses the Apdex formula for that calculation: Apdex on ...
https://dev.mysql.com/doc/internals/en/implementing-index-next-method.html
The [custom-engine.html#custom-engine-api-reference-index_next index_next()] method is used for index scanning: int ha_foo::index_next(byte * buf) The *buf parameter is populated with the row that corresponds to the next matching key value ...
https://dev.mysql.com/doc/internals/en/implementing-index-prev-method.html
The [custom-engine.html#custom-engine-api-reference-index_prev index_prev()] method is used for reverse index scanning: int ha_foo::index_prev(byte * buf) The *buf parameter is populated with the row that corresponds to the previous matching key ...
https://dev.mysql.com/doc/refman/8.4/en/collation-diagnostics.html
The MySQL server generates diagnostics when it finds problems while parsing the Index.xml file: Unknown tags are written to the error log. For example, the following message results if a collation definition contains a <aaa> tag: [Warning] Buffered ...