Comments on: Rebuilding Indexes Will Reset Index Usage Statistics in SQL Server 2012

By: HASH Index - ???? ???????

HASH Index - ???? ??????? — Mon, 01 Jul 2024 09:33:45 +0000

[…] https://thomaslarock.com/2013/01/rebuilding-indexes-will-reset-index-usage-statistics-in-sql-server-… […]

By: Roni Vered Adar

Roni Vered Adar — Mon, 07 Jan 2013 11:28:00 +0000

We’re working on 2008, and I was just about to write a comment that rebuilding doesn’t reset the index usage statistics, until I’ve read the other comments 🙂

It’s a very important behavior change in 2012.

By: ThomasLaRock

ThomasLaRock — Mon, 07 Jan 2013 00:45:00 +0000

In reply to Marios Philippopoulos. Happy to help!

By: Marios Philippopoulos

Marios Philippopoulos — Sun, 06 Jan 2013 21:19:00 +0000

This is terrible news, we have to get Microsoft to fix this for SQL 2012.

I collect index stats every 12 hrs but I only archive this info after instance restarts! Looks like I should start archiving it after index rebuilds as well.

Thank you for this post,
Marios Philippopoulos

By: ThomasLaRock

ThomasLaRock — Sat, 05 Jan 2013 19:52:00 +0000

In reply to Feodor Georgiev. Oh yes, it makes perfect sense as to why it happens.

By: Feodor Georgiev

Feodor Georgiev — Sat, 05 Jan 2013 19:43:00 +0000

In reply to ThomasLaRock.

It only makes sense – the datatypes for the user_scans column from sys.dm_db_index_usage_stats is bigint, so as soon as the limit is reached, it will have to go back from the start.
Whether it is to the boundry of the negative numbers or to 0, the results of the DMVs will be skewed.
In other words, your post has a very good point – we can’t trust the DMVs over a very log periods of time.

By: ThomasLaRock

ThomasLaRock — Sat, 05 Jan 2013 16:09:00 +0000

In reply to Feodor Georgiev. No, I had not seen that for the index usage DMVs, but I have seen that behavior in other areas for SQL Server. IIRC, the GUI used to show a negative number for data file size in SQL 2005 once in a while. I haven't seen it in years though.