On 4 June 2016 at 14:10, Christophe Pettus <xof@thebuild.com> wrote:
> Something I've noticed frequently is that HashAggregate will, especially if the children are Append with one of the
nodesa non-seqscan, estimate 200 rows rather than a calculated vlaue. Where is that value coming from? The statistics
target,a hardwired constant, or something else?
Most likely from DEFAULT_NUM_DISTINCT in selfuncs.h. This is the
fallback, when nothing else can be used.
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