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https://dev.mysql.com/doc/refman/9.7/en/innodb-transaction-isolation-levels.html
For locking reads (SELECT with FOR UPDATE or FOR SHARE), UPDATE, and DELETE statements, locking depends on whether the statement uses a unique index with a unique search condition, or a range-type search condition. For a unique index with a unique ... Transaction isolation is one of the foundations of database ...
https://dev.mysql.com/doc/refman/9.7/en/invisible-indexes.html
For example, an index continues to be updated per changes to table rows, and a unique index prevents insertion of duplicates into a column, regardless of whether the index is visible or invisible. A table with no explicit primary key may still have ... MySQL supports invisible indexes; that is, indexes that are not used by the ...
https://dev.mysql.com/doc/refman/9.7/en/load-data.html
With IGNORE, new rows that duplicate an existing row on a unique key value are discarded. If you use LOAD DATA on an empty MyISAM table, all nonunique indexes are created in a separate batch (as for REPAIR TABLE). The file can be read from the ...
https://dev.mysql.com/doc/refman/9.7/en/mysql-cluster-mgm-definition.html
(NDB 9.7.0) Each node in the cluster has a unique identity. This ID is used by all internal cluster messages for addressing the node, and so must be unique for each NDB Cluster node, regardless of the type of node. (NDB 9.7.0) Each node in the ...
https://dev.mysql.com/doc/refman/9.7/en/mysql-cluster-params-ndbd.html
MaxNoOfUniqueHashIndexes: Total number of unique hash indexes that can be defined in system. MaxUIBuildBatchSize: Maximum scan batch size to use for building unique keys. Increasing this value may speed up builds of unique keys but impacts ongoing ... The listings in this section provide information about parameters used in the [ndbd] or [ndbd default] sections of a config.ini file for configuring NDB Cluster data ...
https://dev.mysql.com/doc/refman/9.7/en/mysql-cluster-programs-ndb-restore.html
You should use this option prior to inserting new rows into the database; otherwise, it is possible for a row to be inserted that later causes a unique constraint violation when trying to rebuild the indexes. Rebuilding of unique indexes uses disk ... The NDB Cluster restoration program is implemented as a separate command-line utility ndb_restore, which can normally be found in the MySQL bin ...
https://dev.mysql.com/doc/refman/9.7/en/mysqlcheck.html
--repair, -r Command-Line Format --repair Perform a repair that can fix almost anything except unique keys that are not unique. The mysqlcheck client performs table maintenance: It checks, repairs, optimizes, or analyzes tables. Each table is ...
https://dev.mysql.com/doc/refman/9.7/en/mysqlimport.html
--replace, -r Command-Line Format --replace The --replace and --ignore options control handling of input rows that duplicate existing rows on unique key values. If you specify --replace, new rows replace existing rows that have the same unique key ... The mysqlimport client provides a command-line interface to the LOAD DATA SQL ...
https://dev.mysql.com/doc/refman/9.7/en/optimizing-innodb-bulk-data-loading.html
If you have UNIQUE constraints on secondary keys, you can speed up table imports by temporarily turning off the uniqueness checks during the import session: SET unique_checks=0; ... SET unique_checks=1; For big tables, this saves a lot of disk I/O ... These performance tips supplement the general guidelines for fast inserts in Section 10.2.5.1, “Optimizing INSERT ...
https://dev.mysql.com/doc/refman/9.7/en/partitioning-key.html
Partitioning by key is similar to partitioning by hash, except that where hash partitioning employs a user-defined expression, the hashing function for key partitioning is supplied by the MySQL server. NDB Cluster uses MD5() for this purpose; for ...