HP 3000 Manuals HP 3000 Manuals
Analyzing Queries with GENPLAN The GENPLAN statement can be useful in determining the way to write a SELECT, UPDATE, or DELETE statement for maximum performance. GENPLAN lets you see the optimizer's access plan for one ALLBASE/SQL statement at a time. Issue the GENPLAN statement in ISQL, then simply do a SELECT on the temporary table SYSTEM.PLAN within the same transaction. A knowledgeable user may be able to use this information to formulate queries differently, make other design changes to improve performance,[REV BEG] or use the SETOPT statement to override the optimizer's access plan.[REV END] Whenever users have a performance concern about a query, they can use the GENPLAN statement to generate the access plan for the query and display the plan information by doing a SELECT on the temporary table SYSTEM.PLAN. By using GENPLAN and SELECT statements, users can easily investigate the performance question. Refer to the ALLBASE/SQL Advanced Application Programming Guide chapter, "Analyzing Queries with GENPLAN," and the ALLBASE/SQL Reference Manual for more information about the GENPLAN statement. [REV BEG]