Hi Everyone,
I'm in the process of analyzing a sql 2008 database for performance reasons. I have discovered a significant number of DML query plans that seem to show a high operator cost for 'Clustered Index Update' as well for plans that have a 'Clustered Index Insert' operator. By high I mean the operator cost shows one for example of having an estimated cost of 0.030003 (912%). Is this something that I should be concerned about? I'm going to soon (hopefully this week) run 'SET STATISTICS PROFILE ON' to see if that helps explain what might be going on. This particular table's row count is approx 50K. The table has one clustered index on a uniqueidentifier (Random) and one unique non clustered index on a FK column which points to a table that has a row count of approx 260K. There is also a FK to another table with 24 million rows. Most other tables have a similar physical design (PK clustered on random uniqueidentifer surrogate column. FK to this other table with 24 million rows). The system is a OLTP system and is more read intensive than write intensive. About 5 users with write capability in the system at a time. About 10-15 users with read ability active at the same time. Some reports are written against this database.
The update statement does not attempt to update the clustered key column. It's possible it could update the non clustered key column though that typically never changes.
I could try to post the show query plan XML if needed if I can get it to fit into this thread.
Thank You.
Morgan
