As a DBA, I am often asked why is something performing slow, what and why statistics need to be updated or what will cause them to be “off”. My initial question to clients when they pose these questions to me is what changed on your end? Did the data change significantly and did the rebuild or reorganize index job run? Before I get into the answers to these questions from my clients, let me give you some background. So, just to clarify, for most of my clients, I work as a remote part-time DBA, that being said, I manage their database from every aspect including setting up servers, backups/restored, troubleshooting, managing their index’s, etc. and again remotely. So normally, I have setup a jobs that will manage their index’s ranging from a weekly rebuild or even sometimes I use one that I’ve designed that makes a choice to either rebuild or reorganize an index based on fragmentation level. The “general rule of thumb” is reorganize the index for fragmentation from 5% to 29% and rebuild when 30% plus. Those are pretty standard numbers I did not make them up.
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