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https://dev.mysql.com/doc/refman/8.4/en/mathematical-functions.html
One implication of this behavior is that for equal argument values, RAND(N) returns the same value each time, and thus produces a repeatable sequence of column values. It is a fast way to generate random numbers on demand that is portable between ...
https://dev.mysql.com/doc/refman/8.4/en/miscellaneous-optimization-tips.html
To fix any compression issues that occur with ARCHIVE tables, use OPTIMIZE TABLE. If possible, classify reports as “live” or as “statistical”, where data needed for statistical reports is created only from summary tables that are generated ... This section lists a number of miscellaneous tips for improving query processing speed: If your application makes several database requests to perform related updates, combining the statements into a stored routine can help ...
https://dev.mysql.com/doc/refman/8.4/en/multiple-column-indexes.html
If you specify the columns in the right order in the index definition, a single composite index can speed up several kinds of queries on the same table. Note As an alternative to a composite index, you can introduce a column that is “hashed” ...
https://dev.mysql.com/doc/refman/8.4/en/myisamchk-memory.html
If you are going to use myisamchk on very large tables, you should first decide how much memory you want it to use. The following formula yields the amount of space required: (largest_key + row_pointer_length) * number_of_rows * 2 You can check the ...myisamchk uses no more memory than its memory-related variables are set ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-logging-management-commands.html
The following table describes the default setting (for all data nodes) of the cluster log category threshold. Table 25.26 Cluster log categories, with default threshold setting Category Default threshold (All data nodes) STARTUP 7 SHUTDOWN 7 ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-ndb-innodb-engines.html
For those unaccustomed to working with NDB, unexpected behaviors can arise due to its distributed nature with regard to transactions, foreign keys, table limits, and other characteristics. The NDB storage engine is implemented using a distributed, ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-nodes-groups.html
However, it is also possible to employ user-defined partitioning with NDBCLUSTER tables. This is subject to the following limitations: Only the KEY and LINEAR KEY partitioning schemes are supported in production with NDB tables. The maximum number ... This section discusses the manner in which NDB Cluster divides and duplicates data for ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-programs-ndb-top.html
This user must be able to read tables in the ndbinfo database (ndb_top uses information from ndbinfo.cpustat and related tables). The following table includes all options that are specific to the NDB Cluster program ndb_top. ndb_top displays ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-programs-ndbd.html
The ndbd binary provides the single-threaded version of the process that is used to handle all the data in tables employing the NDBCLUSTER storage engine. Options that can be used with ndbd are shown in the following table. The option also causes ...This data node process enables a data node to accomplish distributed transaction handling, node recovery, checkpointing to disk, online backup, and related ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-rolling-restart.html
To free memory previously allocated to a table by successive INSERT and DELETE operations, for re-use by other NDB Cluster tables. Other parameters require that the data node be stopped completely using the management client STOP command, then ...