The EXPLAIN facility provides the capability to capture and view detailed information about the access plan chosen for a particular SQL statement. This information includes performance data that can be used to identify poorly written or executing queries.
The EXPLAIN facility uses a special set of tables to store the information about the queries. These tables can be created by running the EXPLAIN.DDL script found in the sqllib/misc directory or by executing the SYSINSTALLOBJECTS procedure:
CALL SYSPROC.SYSINSTALLOBJECTS
('EXPLAIN', 'C', CAST (NULL AS VARCHAR (128)), 'DBA');
The following table showcases the different tools available within the Db2 Explain facility. The visual explain tool is a graphical interface provided through the IBM Data Server Manager (DSM) to view the access plans for a set of SQL statements. The db2exfmt...