CICS LSR Buffer pool screens seem incorrect

Products

• SYSVIEW Performance Management

Issue/Introduction

I am reviewing our CICS LSR buffers and performing any tuning as required.   I wanted to use the SYSVIEW panels as an initial starting point to address those with the worst lookaside rates. However, as I look through the associated panels, the data seems inconsistent. For example, I have a single file defined to LSRPool2 in a region. LSRPools shows a lookaside PCT of 0, with 174K reads and 0 lookaside hits. I selected the Buffer display for the pool and I see 174K reads with 0 Lookasides. I select VSam to view the detail. This shows 457K reads with 174K DExcps. To me this means data is being incorrectly rolled up. These are the 3 displays: LSRPOOLs, LSRBUFF and VSAM File performance: 

Resolution

The REQUESTS column includes Retrieves, Updates, Inserts, Deletes, and Extends. The READS column represents Retrieves only. These statistics are the values taken since the file was opened.

The DExcp count is obtained directly from IBM VSAM control blocks for the dataset.   As noted in the online help screens, these are the DATA EXCP's,. Also, the IExcp shows the INDEX portion of the VSAM dataset. These are also real time values, unlike a LISTCAT would only provide stats from the last open or close on the file.
 
If you are reading data sequentially, you most likely will not get many Look Aside hits and you can also be flushing the buffers which would also result in lack of LkHits
 
Additional vsam tuning would be warranted.