Access paths no longer valid

540 pts.
Tags:
AS/400 Access Paths
iSeries performance
QRY
SQL
Ok, the plot thickens. I'm trying to identify and rebuild LFs that after an abnormal shutdown and normal ipl, are no longer being selected for SQL and QRY. These files are not damaged, but program response has taken a major hit due to these views not being selected. After researdhing one known file before and after rebuilding, the discrepancies that I find are that 1. access path valid field was set to "N" (MBINDX field is dspfd) 2. Index entry Count was = 0 3. Index size was miniscule These LFs have gone from heavy daily usage to *none. Recompiling the LF corrects the problem. How and why does the MBINDX field get set to "N"? What's considered a valid access path?

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I’m not sure what causes this to happen but if you change your logical files to rebuild the access paths during your IPL, you will not suffer the performance hit you describe. However, your IPL may take longer.

Here is an article that give and idea of what to do.

http://search400.techtarget.com/expert/KnowledgebaseAnswer/0,289625,sid3_gci837033_mem1,00.html

That sounds like what may have happened… After a power loss here ( before our UPS ) we had the same type of issue. On the IPL we bypassed the re-building of the LF’s and response time after the IPL was done was painfully slow.

The first time a logical file is accessed it rebuilds the index when the file opens.
A recompile will build it as part of the process by default.

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