Oracle 5.0 Reference Manual page 501

Controls the heuristics applied during query optimization to prune less-promising partial plans
from the optimizer search space. A value of 0 disables heuristics so that the optimizer performs an
exhaustive search. A value of 1 causes the optimizer to prune plans based on the number of rows
retrieved by intermediate plans. This variable was added in MySQL 5.0.1.
•
optimizer_search_depth
Version Introduced
Command-Line Format
Option-File Format
Option Sets Variable
Variable Name
Variable Scope
Dynamic Variable
The maximum depth of search performed by the query optimizer. Values larger than the number of
relations in a query result in better query plans, but take longer to generate an execution plan for
a query. Values smaller than the number of relations in a query return an execution plan quicker,
but the resulting plan may be far from being optimal. If set to 0, the system automatically picks a
reasonable value. If set to 63, the optimizer switches to the algorithm used in MySQL 5.0.0 (and
previous versions) for performing searches. This variable was added in MySQL 5.0.1.
• [481]
pid_file
Command-Line Format
Option-File Format
Option Sets Variable
Variable Name
Variable Scope
Dynamic Variable
The path name of the process ID (PID) file. This variable can be set with the
option.
• [481]
plugin_dir
Version Introduced
Command-Line Format
Option-File Format
Option Sets Variable
Variable Name
Variable Scope
Dynamic Variable
Server System Variables
[481]
5.0.1
--optimizer_search_depth[=#]
optimizer_search_depth
Yes,
optimizer_search_depth
optimizer_search_depth
Global, Session
Yes
Permitted Values
Type
numeric
Default
62
--pid-file=file_name
pid-file=file_name
Yes, [481]
pid_file
pid_file
Global
No
Permitted Values
Type
file name
5.0.67
--plugin_dir=path
plugin_dir
Yes, [481]
plugin_dir
plugin_dir
Global
No
481
[481]
--pid-file
[417]