Without any changes in the database schema or the query, the execution time went from 10 seconds to about 2h30. The table has 1.04 million rows. Additional info: if executing a "SELECT *" against this table, it executed in around 15 seconds; if executing a "SELECT ColX", the execution time went up to 1 minute.
Updated the statistics, rebuilt the clustered PK, but no changes in the performance were seen.
The query was improved, and this version is no longer in use, but I still would like to know what was the cause of this huge performance degradation.
The server is a SQL Server 2008R2.
By LOliveira 1 asked Jun 30, 2015 at 10:01 AM