RE: Index Skip Scan - Mailing list pgsql-hackers

From Floris Van Nee
Subject RE: Index Skip Scan
Date
Msg-id 105fd98b36dc4c0cb6b3dc41106b5556@opammb0562.comp.optiver.com
Whole thread Raw
In response to Re: Index Skip Scan  (Peter Geoghegan <pg@bowt.ie>)
Responses Re: Index Skip Scan  (Dmitry Dolgov <9erthalion6@gmail.com>)
Re: Index Skip Scan  (Peter Geoghegan <pg@bowt.ie>)
List pgsql-hackers
> Note in particular that index scans cannot return the same index tuple twice -
> - processing a page at a time ensures that that cannot happen.
> 
> Can a loose index scan return the same tuple (i.e. a tuple with the same heap
> TID) to the executor more than once?
> 

The loose index scan shouldn't return a tuple twice. It should only be able to skip 'further', so that shouldn't be a
problem.Out of curiosity, why can't index scans return the same tuple twice? Is there something in the executor that
isn'table to handle this?
 

-Floris


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