Lists the Statement Processing configuration metrics and provides a brief description of each.
Table 5.29 Statement Processing Configuration Metrics
| Name | Description |
|---|---|
| Auto Is Null Enabled (Total) | 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 (Total) | 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 (Total) | 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. |
| Div Precision Increment (Total) | 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 (Total) | The maximum permitted result length in bytes for the GROUP_CONCAT() function. |
| Max Error Count (Total) | The maximum number of error, warning, and note messages to be stored for display by the SHOW ERRORS and SHOW WARNINGS statements. |
| Max Join Size (Total) | 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 (Total) | Limits the total number of prepared statements in the server. |
| Max Sp Recursion Depth (Total) | 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 (Total) | After this many write locks, permit some pending read lock requests to be processed in between. |
| Notes Enabled (Total) | 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 (Total) | 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 (Total) | 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 (Total) | 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. |
| Warnings Enabled (Total) | This variable controls whether single-row INSERT statements produce an information string if warnings occur. |