[postgis-devel] CLUSTER in 8.3

Kevin Neufeld kneufeld at refractions.net
Fri Dec 5 09:52:07 PST 2008

Mark Cave-Ayland wrote:
  > I think the GiST part is a red herring - there is no way that a "SELECT
> COUNT(*) FROM foo" can use an index in PostgreSQL. My suspicion is that 
> it's related to the use of ANALYZE/VACUUM/CLUSTER.

Maybe.  You're right that "SELECT ..." doesn't use the index, but the CLUSTER physically reorders the table based on the 
index.  If there is a bizzare bug in our GiST implementation that produces an empty traversal list some of the time, the 
table would be empty.

Never mind, I just saw Paul's post.  This is good news for us in that it's not related to our implementation of GiST ... 
  but it still could be related to PostgreSQL's implementation, no?

-- Kevin

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