On Monday 26 September 2011 19:39, Marc Cousin wrote:
> Because Index Scans are sorted, not Bitmap Index Scans, which builds a
> list of pages to visit, to be then visited by the Bitmap Heap Scan step.
>
> Marc.
Where does this bitmap index scan come from? It seems to negate the advantages
of b-tree indexes described in the section "Indexes and ORDER BY" of the
manual. If I do "set enable_bitmapscan = off;" the query runs a bit faster
although with a larger time range it reverts to a sequential scan.
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