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https://dev.mysql.com/doc/refman/8.0/en/innodb-statistics-estimation.html
Enabling innodb_stats_on_metadata may reduce access speed for schemas that have a large number of tables or indexes, and reduce stability of execution plans for queries that involve InnoDB tables. This technique is especially important for large ...
https://dev.mysql.com/doc/refman/8.0/en/table-scan-avoidance.html
You are comparing indexed columns with constant values and MySQL has calculated (based on the index tree) that the constants cover too large a part of the table and that a table scan would be faster. This is common for tables with fewer than 10 rows ... The output from EXPLAIN shows ALL in the type column when MySQL uses a full table scan to resolve a ...
https://dev.mysql.com/doc/refman/8.0/en/replication-features-differing-tables.html
It is usually possible to replicate from a column of a given data type to another column of the same type and same size or width, where applicable, or larger. Row-based replication supports attribute promotion and demotion between smaller data types ...Attribute promotion can be used with both statement-based and row-based replication, and is not dependent on the storage engine used by either the source or the ...
https://dev.mysql.com/doc/refman/8.0/en/blob.html
The maximum size of a BLOB or TEXT object is determined by its type, but the largest value you actually can transmit between the client and server is determined by the amount of available memory and the size of the communications buffers. A BLOB is ...These differ only in the maximum length of the values they can ...
https://dev.mysql.com/doc/refman/8.0/en/group-replication-message-compression.html
Messages that have a payload larger than the specified number of bytes are compressed. Note that the maximum supported input size for the LZ4 compression algorithm is 2113929216 bytes. This limit is lower than the maximum possible value for the ...
https://dev.mysql.com/doc/refman/8.0/en/replication-solutions-backups.html
There are therefore two choices: If you are using replication as a solution to enable you to back up the data on the source, and the size of your database is not too large, the mysqldump tool may be suitable. How you back up a database depends on ...
https://dev.mysql.com/doc/refman/8.0/en/mysql-cluster-limitations-transactions.html
To ensure that a given transaction reads only before or after values, you can impose row locks using SELECT ... LOCK IN SHARE MODE causes shared row locks to be used; FOR UPDATE causes exclusive row locks to be used. To avoid modification of the ...
https://dev.mysql.com/doc/refman/8.0/en/mysql-cluster-disk-data-objects.html
This log file group is to be made up of two undo log files, which we name undo_1.log and undo_2.log, whose initial sizes are 16 MB and 12 MB, respectively. (The default initial size for an undo log file is 128 MB.) Optionally, you can also specify a ... NDB Cluster Disk Data storage is implemented using the following objects: Tablespace: Acts as containers for other Disk Data ...
https://dev.mysql.com/doc/refman/8.0/en/performance-schema-statement-summary-tables.html
By default, the table is autosized, but if this size is too small, set the performance_schema_digests_size system variable to a larger value at server startup. The QUERY_SAMPLE_TEXT, QUERY_SAMPLE_SEEN, and QUERY_SAMPLE_TIMER_WAIT columns also are ...
https://dev.mysql.com/doc/refman/8.0/en/string-type-syntax.html
The effective maximum length of a VARCHAR is subject to the maximum row size (65,535 bytes, which is shared among all columns) and the character set used. See Section 10.4.7, “Limits on Table Column Count and Row Size”. If this is done, MySQL ...