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BufferPool Performance Analysis Beyond the Basic Hit Ratio.....BufferPool Performance Analysis Beyond the Basic Hit Ratio.....855+*/********************************************************************/856+*/* IFC ID 0007 FOR RMID 10 RECORDS THE COMPLETION CODE AFTER */857+*/* THE READ I/O OPERATION */858+*/********************************************************************/859+*860+QW0007 DSECT IFCID(QWHS0007)861+QW0007MM DS F MEDIA MANAGER RETURN CODE - 0 SUCCESSFUL862+QW0007DB DS XL2 DATABASE ID (DBID)863+QW0007OB DS XL2 PAGESET OBID864+QW0007AC DS F ACE TOKEN OF ACTUAL REQUESTOR.865+* THIS MAY DIFFER FROM THE ACE TOKEN IN THE STANDARD866+* HEADER FOR THIS RECORD, EG IN SEQUENTIAL PREFETCH.867+QW0007NP DS H NUMBER OF PAGES READ
Notes:
The IFCID 7 record now must be matched with the 6 record, and shows how many pages were actually read into the bufferpool by the read request. Synchronous I/O is obvious at one page. However, Sequential, LP, and Dynamic may physically read anywhere from one through 32 pages into the pool....only those pages in the requested range that were not in the pool. The 6 & 7 records also contain the ACE (Application Control Element) that can be match to a user address space to determine the planname and/or authid. For prefetch, there are two ACEs involved, the actual requestor, and the ACE of the Database Manager Address Space.
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