SQL/MX 2.x Installation and Management Guide (G06.24+, H06.03+)

Managing Database Applications
HP NonStop SQL/MX Installation and Management Guide—523723-004
11-15
Recompiling a Module
If a plan requires automatic recompilation, you should explicitly recompile the module.
See Recompiling a Module on page 11-15.
Recompiling a Module
Periodically, depending on changes to the database or the occurrence of automatic
recompilation, you might need to recompile the modules of an application. Explicitly
recompiling modules generates optimal query execution plans and prevents the
performance cost of automatic recompilation.
Consider putting recompilation commands in a script file to automate the process of
recompiling modules.
For more information, see the SQL/MX Programming Manual for C and COBOL and
the SQL/MX Programming Manual for Java.
Migrating SQL/MX Nodes to Obtain Improved Query Plan
Performance
New releases of NonStop SQL/MX sometimes provide enhancements to query
execution plan performance over previous releases. To achieve these performance
enhancements on all the SQL/MX nodes in a distributed database, you must migrate
the nodes that contain an earlier release of NonStop SQL/MX to the new release.
For more information about the performance features of query execution plans, see the
SQL/MX Query Guide. For more information about migrating SQL/MX databases, see
Section 14, Migrating an SQL/MP Database to NonStop SQL/MX Release 2.1 or
Release 2.0.
Displaying and Analyzing Query Execution Plans
Use the EXPLAIN function to display the query execution plans of a module. For more
information, see the SQL/MX Programming Manual for C and COBOL, the SQL/MX
Programming Manual for Java, and the SQL/MX Reference Manual.
For details on how to analyze query execution plans and determine an optimal plan,
see the SQL/MX Query Guide.
Managing Modules
Topics in this subsection:
•
Producing Locally Placed Modules or Globally Placed Modules on page 11-16
•
Securing User Modules on page 11-17
•
Checking Module Dependencies With DISPLAY USE OF on page 11-20
•
Removing Modules on page 11-22
•
Converting Globally Placed Modules to Locally Placed Modules on page 11-23