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gregoryagu
Yak Posting Veteran
80 Posts |
 Posted - 2008-07-14 : 14:36:48
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| I have a table which uses as its primary key a uniqueidentifier (Guid). This column was indexed, but the table was a heap - ie no clustered index.So I turned the index into a clustered index and queries now run much faster.However, a co-worker says that this is not a good idea - that a GUID should not be a clustered index as it will cause page fragmentation over time as we are not using a seqential GUID.Is he correct? Is this not a good idea? I have done many tests and indeed having a clustered index improves the speed dramatically.The table is not an a high use table, many more reads than writes, a typical customer name address etc. In other words, there is not a lot of updates going on in the table.So, is there a downside to using the Guid as the clustered index?Greg |
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tkizer
Almighty SQL Goddess
38200 Posts |
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visakh16
Very Important crosS Applying yaK Herder
52326 Posts |
Posted - 2008-07-14 : 14:44:33
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| I've also heard that its not recommended to use GUID as clustered indexes. We are always told to use identity columns as clustered indexes. |
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gregoryagu
Yak Posting Veteran
80 Posts |
Posted - 2008-07-14 : 15:08:52
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| The following quote is all that I could find on searching SQLTeam on "UniqueIdentifier Clustered Index" Is there a better search phrase?"GUIDs are not good candidates for clustered indexes, especially on tables that have a lot of insert activity. But they are perfectly fine for non-clustered indexes."I agree that an indentity column would be better, but in this case, the database is already in production and I can't change that aspect of it. Also there is not a lot of insert activity on the table. The guid is used in almost all of the joins, so there I don't see a way around using it as a clustered index. The table in question is only two fields, the guid and an SQLVarient. Greg |
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UniqueIdentifier as Clustered Index