"Frank Millman" <fr...@chagford.com> writes:
> Pavel Stehule wrote:
>> 2017-09-12 8:45 GMT+02:00 Frank Millman <fr...@chagford.com>:
>>> I am experimenting with optimising a SQL statement. One version uses 4
>>> LEFT JOIN’s and a 5-way CASE statement in the body. 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
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