Re: Unused index influencing sequential scan plan

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On 18 October 2012 17:11, Thom Brown <thom@xxxxxxxxx> wrote:
> The estimate is down to almost a 10th of what it was before.  What's going on?

Even though the index isn't used, the pg_statistic entries that the
expression index would have made available are. It's as if you
materialised the expression into a column, analyzed and grouped by
that.

-- 
Peter Geoghegan       http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training and Services


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