7.33 Statement Processing Configuration Metrics

Lists the Statement Processing configuration metrics and provides a brief description of each.

Table 7.33 Statement Processing Configuration Metrics

Name	Description
Auto Is Null Enabled	If this variable is set to 1, then after a statement that successfully inserts an automatically generated AUTO_INCREMENT value, you can find that value by issuing a statement of the following form: SELECT * FROM tbl_name WHERE auto_col IS NULL If the statement returns a row, the value returned is the same as if you invoked the LAST_INSERT_ID() function.
Big Selects Enabled	If set to 0, MySQL aborts SELECT statements that are likely to take a very long time to execute (that is, statements for which the optimizer estimates that the number of examined rows exceeds the value of max_join_size). This is useful when an inadvisable WHERE statement has been issued.
Buffer Result Enabled	If set to 1, sql_buffer_result forces results from SELECT statements to be put into temporary tables. This helps MySQL free the table locks early and can be beneficial in cases where it takes a long time to send results to the client.
Cte Max Recursion Depth	The common table expression (CTE) maximum recursion depth. The server terminates execution of any CTE that recurses more levels than the value of this variable.
Div Precision Increment	Indicates the number of digits by which to increase the scale of the result of division operations performed with the / operator.
Group Concat Max Len	The maximum permitted result length in bytes for the GROUP_CONCAT() function.
Internal Tmp Disk Storage Engine	The storage engine for on-disk internal temporary tables. Permitted values are MYISAM and INNODB.
Internal Tmp Mem Storage Engine	The storage engine for in-memory internal temporary tables. Permitted values are TempTable and MEMORY.
Max Digest Length	The maximum number of bytes available for computing statement digests. When this amount of space is used for computing the digest for a statement, no further tokens from the parsed statement are collected or figure into the digest value. Statements differing only after that many bytes of parsed statement tokens produce the same digest and are aggregated for digest statistics.
Max Error Count	The maximum number of error, warning, and note messages to be stored for display by the SHOW ERRORS and SHOW WARNINGS statements.
Max Execution Time	The execution timeout for SELECT statements, in milliseconds. If the value is 0, timeouts are not enabled.
Max Join Size	Do not permit statements that probably need to examine more than max_join_size rows (for single-table statements) or row combinations (for multiple-table statements) or that are likely to do more than max_join_size disk seeks.
Max Prepared Stmt Count	Limits the total number of prepared statements in the server.
Max Sp Recursion Depth	The number of times that any given stored procedure may be called recursively. Stored procedure recursion increases the demand on thread stack space. If you increase the value of max_sp_recursion_depth, it may be necessary to increase thread stack size by increasing the value of thread_stack at server startup.
Max Write Lock Count	After this many write locks, permit some pending read lock requests to be processed in between.
Notes Enabled	If set to 1 (the default), warnings of Note level increment warning_count and the server records them. If set to 0, Note warnings do not increment warning_count and the server does not record them.
Quote Show Create Enabled	If set to 1 (the default), the server quotes identifiers for SHOW CREATE TABLE and SHOW CREATE DATABASE statements. If set to 0, quoting is disabled.
Safe Updates Enabled	If set to 1, MySQL aborts UPDATE or DELETE statements that do not use a key in the WHERE clause or a LIMIT clause. This makes it possible to catch UPDATE or DELETE statements where keys are not used properly and that would probably change or delete a large number of rows.
Select Limit	The maximum number of rows to return from SELECT statements. The default value for a new connection is the maximum number of rows that the server permits per table.
Temptable Max Ram	Defines the maximum amount of memory (in bytes) that can be occupied by the TempTable storage engine before data is stored on disk.
Warnings Enabled	This variable controls whether single-row INSERT statements produce an information string if warnings occur.