EXPLAIN table changes in DB2 10
Before you can use EXPLAIN, you must create an EXPLAIN table to hold the captured information. Certain optimization tools depend on instances of EXPLAIN tables. You can create and maintain a set of EXPLAIN tables, or SQL optimization tools also create and maintain instances of EXPLAIN tables.
Tables of the correct format for DB2® 10 are created when you run the DSNTIJRT installation job. You can also view the SQL statements for creating EXPLAIN tables in the correct format for DB2 10 in member DSNTESC of the SDSNSAMP library.
Important: 
It
is best to convert EXPLAIN tables to DB2 10
format during migration, or soon after migration.
In DB2 10, the
EXPLAIN function supports tables that have only the DB2 10, DB2 9, or Version 8 formats. However, DB2 9 format and Version 8 format EXPLAIN tables are deprecated. If you
invoke EXPLAIN and DB2 9 or Version 8 tables are used, DB2 issues SQL code +20520. If
tables of an unsupported format are found, DB2 issues SQL code -20008 and the
EXPLAIN operation fails.
It
is best to convert EXPLAIN tables to DB2 10
format during migration, or soon after migration.
In DB2 10, the
EXPLAIN function supports tables that have only the DB2 10, DB2 9, or Version 8 formats. However, DB2 9 format and Version 8 format EXPLAIN tables are deprecated. If you
invoke EXPLAIN and DB2 9 or Version 8 tables are used, DB2 issues SQL code +20520. If
tables of an unsupported format are found, DB2 issues SQL code -20008 and the
EXPLAIN operation fails.All EXPLAIN tables must be encoded in UNICODE format to be compatible with DB2 10 new-function mode.
