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Truncate before table drop


Truncate before table drop

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Daniel Fountain
Daniel Fountain
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Hi all,

I have come across some code that does this:

Truncate table Tablename
Drop table Tablename

I have never done a truncate before a drop. I have looked online for reasoning behind this (some people have suggested its quicker, but i have yet to see this proved), but most posts seem to break down into arguments over saying truncate isn't logged (it is!).

So has anyone found if this is actually quicker?

Dan
vijred
vijred
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I believe the performance gain with truncate before drop is minimal to no gain. This is what I could practically see while deleting large table!

-Vijred (http://vijredblog.wordpress.com)
Sean Lange
Sean Lange
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I would think that it is actually slower. Both truncate and drop will deallocate pages. These page deallocations are what is logged in a truncate and a drop. This basically means we have two implicit transactions instead of one. The first to deallocate all the pages and a second to drop the table. It would be interesting to see some stats or references where people claim that truncating and then dropping is faster.

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GilaMonster
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Doing that is pointless. Truncate deallocates all pages, Drop deallocates all pages and removes the metadata

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

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