7.25 Optimizer Configuration Metrics

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

Table 7.25 Optimizer Configuration Metrics

Name	Description
End Markers In Json Enabled	Whether optimizer JSON output adds end markers.
Eq Range Index Dive Limit	Indicates the number of equality ranges in an equality comparison condition when the optimizer switches from using index dives to index statistics in estimating the number of qualifying rows.
Histogram Generation Max Mem Size	The maximum amount of memory available for generating histogram statistics.
Max Length For Sort Data	The maximum size of parameter values that can be sent with the mysql_stmt_send_long_data() C API function.
Max Seeks For Key	Limit the assumed maximum number of seeks when looking up rows based on a key.
Max Sort Length	The number of bytes to use when sorting data values. Only the first max_sort_length bytes of each value are used; the rest are ignored.
Prune Level Enabled	Controls the heuristics applied during query optimization to prune less-promising partial plans from the optimizer search space.
Range Alloc Block Size	The size of blocks (in bytes) that are allocated when doing range optimization.
Search Depth	The maximum depth of search performed by the query optimizer.
Switch Value	The optimizer_switch system variable enables control over optimizer behavior.
Trace	Controls how to enable optimizer tracing.
Trace Features	Enables or disables selected optimizer tracing features.
Trace Limit	The maximum cumulative size of stored optimizer traces.
Trace Max Mem Size	The maximum cumulative size of stored optimizer traces.
Trace Offset	The offset of optimizer traces to display.
Windowing Use High Precision Enabled	Whether to compute window operations without loss of precision. Default is ON.