Search Results
https://dev.mysql.com/doc/refman/8.4/en/number-literals.html
Number literals include exact-value (integer and DECIMAL) literals and approximate-value (floating-point) literals. Numbers may be preceded by - or + to indicate a negative or positive value, respectively. Numbers represented in scientific notation ...
https://dev.mysql.com/doc/refman/8.4/en/obtaining-loadable-function-information.html
The Performance Schema user_defined_functions table contains information about the currently installed loadable functions: SELECT * FROM performance_schema.user_defined_functions; The mysql.func system table also lists installed loadable functions, ...
https://dev.mysql.com/doc/refman/8.4/en/open.html
OPEN cursor_name This statement opens a previously declared cursor. For an example, see Section 15.6.6, “Cursors”. ...
https://dev.mysql.com/doc/refman/8.4/en/optimize-blob.html
When storing a large blob containing textual data, consider compressing it first. Do not use this technique when the entire table is compressed by InnoDB or MyISAM. For a table with several columns, to reduce memory requirements for queries that do ...
https://dev.mysql.com/doc/refman/8.4/en/optimize-overview.html
Database performance depends on several factors at the database level, such as tables, queries, and configuration settings. These software constructs result in CPU and I/O operations at the hardware level, which you must minimize and make as ...
https://dev.mysql.com/doc/refman/8.4/en/optimizer-trace-implementation.html
A trace is started by creating an instance of Opt_trace_start; information is added to this trace by creating instances of Opt_trace_object and Opt_trace_array, and by using the add() methods of these classes.
https://dev.mysql.com/doc/refman/8.4/en/optimizing-innodb-ddl-operations.html
Many DDL operations on tables and indexes (CREATE, ALTER, and DROP statements) can be performed online. Online DDL support for adding secondary indexes means that you can generally speed up the process of creating and loading a table and associated ...
https://dev.mysql.com/doc/refman/8.4/en/optimizing-innodb-logging.html
Consider the following guidelines for optimizing redo logging: Increase the size of your redo log files. When InnoDB has written redo log files full, it must write the modified contents of the buffer pool to disk in a checkpoint. InnoDB tries to ...
https://dev.mysql.com/doc/refman/8.4/en/optimizing-innodb-many-tables.html
If you have configured non-persistent optimizer statistics (a non-default configuration), InnoDB computes index cardinality values for a table the first time that table is accessed after startup, instead of storing such values in the table. This ...
https://dev.mysql.com/doc/refman/8.4/en/optimizing-innodb-queries.html
To tune queries for InnoDB tables, create an appropriate set of indexes on each table. Follow these guidelines for InnoDB indexes: Because each InnoDB table has a primary key (whether you request one or not), specify a set of primary key columns ...