"Frank Millman" <frank@chagford.com> writes:
> Pavel Stehule wrote:
>> 2017-09-12 8:45 GMT+02:00 Frank Millman <frank@chagford.com>:
>>> I am experimenting with optimising a SQL statement. One version uses 4 LEFT JOIN’s and a 5-way CASE statement in
thebody. The second moves the filtering into the JOIN section, and I end up with 16 LEFT JOIN’s and no CASE statements.
>> you can experimentally try increase FROM_COLLAPSE_LIMIT to some higher number 14 maybe 16
> I tried increasing FROM_COLLAPSE_LIMIT, but it made no difference.
For this you need to increase join_collapse_limit, not
from_collapse_limit. (Usually, though, there's little reason not to keep
them the same.)
regards, tom lane
--
Sent via pgsql-general mailing list (pgsql-general@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-general