On Sun, 2 Sep 2012, Peter Geoghegan wrote:
On 2 September 2012 16:26, Sergey Koposov <kopo...@ast.cam.ac.uk> wrote:
That's why we support altering that value with an ALTER TABLE...ALTER
COLUMN DDL statement. You might at least consider increasing the
statistics target for the column first though, to see if that will
make the n_distinct value better accord with reality.
Thanks, I've forgot about that possibility.
After fixing the n_distinct to the correct value the index scan became the
preferred option. and the row number estimate for the index scan became
more realistic
Sorry for the noise.
Sergey
*****************************************************
Sergey E. Koposov, PhD, Research Associate
Institute of Astronomy, University of Cambridge
Madingley road, CB3 0HA, Cambridge, UK
Tel: +44-1223-337-551 Web: http://www.ast.cam.ac.uk/~koposov/
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