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https://dev.mysql.com/doc/refman/8.4/en/timestamp-lookups.html
This phenomenon can lead to different results for a given TIMESTAMP column query, depending on whether the optimizer uses an index to execute the query. Under those conditions, the comparison in the WHERE clause occurs in different ways for ...
https://dev.mysql.com/doc/refman/8.4/en/sys-schema-redundant-indexes.html
The schema_redundant_indexes view displays indexes that duplicate other indexes or are made redundant by them. In the following column descriptions, the dominant index is the one that makes the redundant index redundant. The ...The ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-innodb-cached-indexes-table.html
The INNODB_CACHED_INDEXES table reports the number of index pages cached in the InnoDB buffer pool for each index. Index identifiers are unique across all the databases in an instance. N_CACHED_PAGES The total number of index pages cached in the ...
https://dev.mysql.com/doc/refman/8.4/en/myisam-ftdump.html
It reads the MyISAM index file directly, so it must be run on the server host where the table is located. Before using myisam_ftdump, be sure to issue a FLUSH TABLES statement first if the server is running. myisam_ftdump scans and dumps the entire ...On the other hand, the distribution of words changes infrequently, so it need not be run ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-innodb-ft-index-cache-table.html
The INNODB_FT_INDEX_CACHE table provides token information about newly inserted rows in a FULLTEXT index. Before querying it, set the value of the innodb_ft_aux_table system variable to the name (including the database name) of the table that ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-innodb-ft-index-table-table.html
The INNODB_FT_INDEX_TABLE table provides information about the inverted index used to process text searches against the FULLTEXT index of an InnoDB table. Before querying it, set the value of the innodb_ft_aux_table system variable to the name ...
https://dev.mysql.com/doc/refman/8.4/en/sys-schema-index-statistics.html
The schema_index_statistics and x$schema_index_statistics views have these columns: table_schema The schema that contains the table. select_latency The total wait time of timed reads using the index. insert_latency The total wait time of timed ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-innodb-cmp-per-index-table.html
The INNODB_CMP_PER_INDEX and INNODB_CMP_PER_INDEX_RESET tables provide status information on operations related to compressed InnoDB tables and indexes, with separate statistics for each combination of database, table, and index, to help you ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-ndbinfo-index-columns.html
This table provides information about indexes on NDB tables. The columns of the index_columns table are listed here, along with brief descriptions: table_id Unique ID of the NDB table for which the index is defined Name of the database containing ...
https://dev.mysql.com/doc/refman/8.4/en/rebuilding-tables.html
This section describes how to rebuild or repair tables or indexes, which may be necessitated by: Changes to how MySQL handles data types or character sets. For example, an error in a collation might have been corrected, necessitating a table ...