Question & Answer
Question
In the BPOKWSNT executable in Expert Analysis, BP1, for example, shows up unexpectedly on the last panel even though the user-defined pattern does not include BP1 and the Expert Analysis did not recommend any objects to be assigned to it. Yet it appears in an "ALTER BUFFERPOOL" statement.
Cause
By default, the object placement tool does not process objects that did not have activity during the time the data collection was performed. The objects are therefore left in the buffer pool they are currently assigned to. In the last panel of the tool this can result in a buffer pool being listed although there is no rule to assign objects to that buffer pool.
Answer
Ideally you should collect data at a time where almost all database objects have activity. This is due to the prefetch versus synchronous fetch behavior of objects being very important in deciding their placement, and this information is not available if they have no activity. If this is not possible, concatenate several BPD files from different times where in total most objects can be expected to be active."
Alternately, if you wish to assign objects to buffer pools, regardless of their activity, ensuring that only the buffer pools which have rules in panel 2 will appear in the final placement, go to the object placement screen (screen page 2). Down at the bottom is a field called:
"Assign objects not accessed during data collection. (Only applicable to 'all' keyword)."
When checking this box, ensure that for each buffer pool at least one rule exists that contains the keyword 'ALL' in numerical fields, rather than absolute values. Otherwise inactive objects can not be assigned to these buffer pools. When you got to screen 4, Initial Buffer Pool Sizing, BP1 is no longer showing.
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Document Information
Modified date:
11 February 2021
UID
swg21179450