IBM BPM, V8.0.1, All platforms > Tuning > Advanced tuning > Messaging tuning
Additional schema considerations for the messaging engines
After the SIB table DDL is generated, there are a few changes that should be considered depending on the message sizes. It could be beneficial to resize the page size of the SIB tables based on the physical row size, and then adjust the size as the average row size can be determined.
The following table suggests page sizes for the various SIB table spaces. Define the table spaces as Segmented with a SEGSIZE of 32 to take advantage of the efficient storage management logic provided by segmented table spaces.
SIB and messaging engine tables and table spaces Table name Table space name Page size Buffer pool Additional information SIB000 SIB000TS 32 BP32K Contains large varchar column SIB001 SIB001TS 32 BP32K Contains large varchar column SIB002 SIB002TS 32 BP32K Contains large varchar column SIBCLASSMAP MAPTS 32 BP32K Contains large varchar column SIBKEYS KEYTS 4 BP20 SIBLISTING LISTTS 4 BP20 SIBOWNER OWNERTS 4 BP20 SIBXACTS XACTSTS 4 BP20 SIB000AUX SIB100LS 32 BP32K 100M BLOB SIB001AUX SIB101LS 32 BP32K 100M BLOB SIB002AUX SIB102LS 32 BP32K 100M BLOB The "volatile" specification on the table declaration can cause DB2 for z/OS to select index access when accessing the data in the tables. The volatile attribute is suggested because the SIB tables are treated as queues where data is transient and does not persist long enough to provide meaningful table statistics. The volatile attribute tells DB2 the data is transient so DB2 will not use the existing table statistics to determine the SQL access path. With this attribute, DB2 favors index access. The DDL can be updated to include the volatile attribute, or the tables can be altered after they have been created to receive the volatile attribute.
ALTER TABLE SCHEMA.SIBOWNER VOLATILE; ALTER TABLE SCHEMA.SIBCLASSMAP VOLATILE; ALTER TABLE SCHEMA.SIBLISTING VOLATILE; ALTER TABLE SCHEMA.SIB000 VOLATILE; ALTER TABLE SCHEMA.SIB000AUX VOLATILE; ALTER TABLE SCHEMA.SIB001 VOLATILE; ALTER TABLE SCHEMA.SIB001AUX VOLATILE; ALTER TABLE SCHEMA.SIB002 VOLATILE; ALTER TABLE SCHEMA.SIB002AUX VOLATILE; ALTER TABLE SCHEMA.SIBXACTS VOLATILE; ALTER TABLE SCHEMA.SIBKEYS VOLATILE;