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https://dev.mysql.com/doc/refman/8.4/en/key-space.html
This is for the worst case when all keys are inserted in sorted order and the table doesn't have any compressed keys. You can roughly calculate the size for the index file as (key_length+4)/0.67, summed over all keys. If the first index part is a ...
https://dev.mysql.com/doc/refman/8.4/en/keywords.html
Certain keywords, such as SELECT, DELETE, or BIGINT, are reserved and require special treatment for use as identifiers such as table and column names. This may also be true for the names of built-in functions. Some keywords which are otherwise ...
https://dev.mysql.com/doc/refman/8.4/en/limit-optimization.html
If you need only a specified number of rows from a result set, use a LIMIT clause in the query, rather than fetching the whole result set and throwing away the extra data. MySQL sometimes optimizes a query that has a LIMIT row_count clause and no ...
https://dev.mysql.com/doc/refman/8.4/en/load-xml.html
User variables can be especially useful when you want to insert data from an XML file into table columns whose names do not match those of the XML fields. The tagname in the optional ROWS IDENTIFIED BY clause must also be given as a literal string, ...
https://dev.mysql.com/doc/refman/8.4/en/log-destinations.html
INSERT, DELETE, and UPDATE cannot be used on a log table. MySQL Server provides flexible control over the destination of output written to the general query log and the slow query log, if those logs are enabled. Possible destinations for log ...
https://dev.mysql.com/doc/refman/8.4/en/mathematical-functions.html
ABS(X) Returns the absolute value of X, or NULL if X is NULL. An implication of this is that ABS(-9223372036854775808) produces an error because the result cannot be stored in a signed BIGINT value. mysql> SELECT ABS(2); -> 2 mysql> SELECT ABS(-32); ...
https://dev.mysql.com/doc/refman/8.4/en/monitor-alter-table-performance-schema.html
stage/innodb/alter table (insert): This stage is repeated for each index added by the ALTER TABLE operation. You can monitor ALTER TABLE progress for InnoDB tables using Performance Schema. There are seven stage events that represent different ...
https://dev.mysql.com/doc/refman/8.4/en/myisam-start.html
bulk_insert_buffer_size The size of the tree cache used in bulk insert optimization. The following options to mysqld can be used to change the behavior of MyISAM tables. Note This is a limit per thread! delay_key_write=ALL Don't flush key buffers ...
https://dev.mysql.com/doc/refman/8.4/en/myisamchk-repair-options.html
An option value of 0 disables updates to all indexes, which can be used to get faster inserts. --correct-checksum Command-Line Format --correct-checksum Correct the checksum information for the table. --data-file-length=len, -D len Command-Line ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-batch-commands.html
For this you can insert statements like this: SELECT '<info_to_display>' AS ' '; The statement shown outputs <info_to_display>. The mysql client typically is used interactively, like this: mysql db_name However, it is also possible to put your SQL ...