Some of our clients have very high forwarded record counts and aren’t aware of it until they run sp_BlitzFirst and get an alert about high Forwarded Records per Second. Some of these clients are using Ola Hallengren‘s IndexOptimize stored procedure to maintain their indexes. This brought up a question of whether or not rebuilding a…
Even with lots of monitoring in place, we should perform periodic checks of our SQL Servers. Think of this like “Spring Cleaning”, except I would recommend that it be more frequently than just once a year. Doing it monthly might be a bit ambitious due to our busy schedules, but quarterly could be achievable. Below are…
I hate rebuilding indexes There. I said it. It’s not fun. I don’t care all that much for reorgs, either. They’re less intrusive, but man, that LOB compaction stuff can really be time consuming. What I do like is updating statistics. Doing that can be the kick in the bad plan pants that you need…
Oh God, he’s talking about statistics again Yeah, but this should be less annoying than the other times. And much shorter. You see, I hear grousing. Updating statistics was bringin’ us down, man. Harshing our mellow. The statistics would just update, man, and it would take like… Forever, man. Man. But no one would actually…
Here’s a handy flowchart for whenever you find yourself worrying about fragmentation: *Talk to your doctor about whether fragmentation is a problem for you. Seek help for index maintenance lasting longer than four hours. Serious side effects may occur if all index maintenance is ignored completely. Brent says: pop quiz: what are you doing more…
Everybody wants to know about index fragmentation It is an inescapable vortex of malaise and confusion. Like that swamp in The Neverending Story that killed the horse. Sorry if you haven’t seen that movie. The horse wasn’t that cool, anyway. Neither is index fragmentation, but it’s not worth losing sleep over. Or a horse. I…
One of the blocking scenarios I find most interesting is related to online index rebuilds. Index rebuilds are only mostly online. In order to complete they need a very high level of lock: a schema modification lock (SCH-M). Here’s one way this can become a big problem: An online index rebuild starts against a large index A…
If you’re a production database administrator responsible for backups, corruption checking, and index maintenance on SQL Server, try Ola Hallengren’s free database maintenance scripts. They’re better than yours (trust me), and they give you more flexibility than built-in maintenance plans. However, the index maintenance defaults aren’t good for everyone. Here’s how they ship: The defaults on…
A while back, we posted about how SQL Server index fragmentation doesn’t matter. That blog post generated a lot of heated discussion and has served to make people aware that fragmentation may not be the source of their woes. Sometimes, though, there are data access patterns where fragmentation really does matter. Perpetual Fragmentation Some data…
Do you rely on index rebuilds to make queries run faster? Or do you always feel like statistics are “bad” and are the cause of your query problems? You’re not alone– it’s easy to fall into the trap of always blaming fragmentation or statistics. Learn why these two tools aren’t the answer to every problem…
I first knew something was up when I looked at the job history for a simple maintenance plan. It had two steps: Rebuild all the indexes in the database – this took 10 minutes each night. Update statistics – this took 2-3 hours each night. What was going on? Statistics in SQL Server are small,…
This question came up in the pre-show chat for our weekly webcast: when you rebuild a nonclustered index offline, does it impact only the nonclustered index? Or does it impact the entire table? Showing is more fun than telling! Let’s take a look. First I restore AdventureWorks to slow storage Sometimes slower storage is handy….
Are you still rebuilding all of your indexes every week – or heaven forbid, every night – and still having performance problems? Odds are, you’re not actually making things better – you’re making them worse! I explain why in this video: For more, read my post: Stop Worrying About Index Fragmentation.
Editors Note: this post was updated in June 2014 to link to an online index rebuild bug that can cause corruption. Once up on a time, there was a database server with 500GB of data and a heavy read workload of dynamic queries. Data was updated frequently throughout the day and index tuning was a…
I’ll never think “I’ve seen it all” when it comes to SQL Server– there’s just always someone waiting around the corner who’s found a weird new thing to do with it. But there are some things I really wish I could stop finding. One of those things I hate finding is bad fillfactor settings. Fillfactor…
I bet you’re worried about your index fragmentation. And I bet you’re wasting your time, missing the real point. What is Index Fragmentation and How It Happens Let’s take a step back for a second and pretend that your database is a phone book organized by last name, first name. As people move into your…
Last week, I blogged about the basics of SQL Server index fragmentation: why it happens, how to fix it, and how often people are fixing it. I left you with a cliffhanger: it seemed that the frequency of defrag jobs didn’t appear to affect fragmentation levels: Databases with no index defragmentation were an average of…
We asked the community for index fragmentation information for data mining purposes, and the results are in – and interesting. Over the next couple of weeks, I’ll talk about some of the results we found in the field. What Is SQL Server Fragmentation? SQL Server stores data in pages. To make things easy, think of…
