I am running Ola Hallengren's maintenance script on a nightly basis and found that it is running 5 to 6 hours on a medium sized set of databases. When I looked into it, I found that it was due to the UPDATE STATs process. Looking at the stats it was updating I found that 90% were system created _WA_Sys stats. There are 82,000 _WA_Sys stats across my 10 databases. Some tables had one for every column.
I know these stats are created by SQL Server for execution plan optimization, but this seems excessive. Why is SQL Server creating so many of these and what can I do to get a handle on it? I assume that if I delete them they will just be recreated. I can't see creating an index for every column on the tables that have a _WA_Sys stat for every column.
Any suggestions?
Jim
