Index maintenance revisited

It’s almost a month since my post on index maintenance based on fragmentation, in which I attempted to show what can be done using simple script and some DMVs. There was some discussion on LinkedIn group SQLDBA about it and I would refer to it with few comments.

  1. The purpose of my script was purely to demonstrate the existence of sys.dm_db_index_physical_stats DMF, which in conjunction with other DMV yields very interesting results.
  2. The script presented by me was very simple, if not simplistic. It does not work well with partitioned indexes (my own findings), offline databases (as pointed out by Sten Westerback) and – what’s more important – it’s only criteria of operation is index fragmentation being completely unaware of size or other constraints. This does not make it a good candidate for running unmodified in production environments.
  3. As per another comment – indeed Microsoft provides very good example in Books Online regarding sys.dm_db_index_physical_stats, which deals with first two of points mentioned above.
  4. Finally, there is a fantastic maintenance tool developed by Ola Hallengren, which gives all kinds of options when it comes to database maintenance. It is successfully used by many DBAs all around world – if you need something to be working out-of-the-box, you might want to give it a try.

The reason why I’m writing this is that I don’t want to be blamed for taking a proof of concept (as my script was) and turning it into a primary maintenance solution. As usual – read, test, ask questions, adapt, share your findings, we all will benefit from that.


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