effective_cache_size patch

On Thu, 2004-11-04 at 16:37, Simon Riggs wrote:

Also, another minor patch which prevents effective_cache_size and
random_page_cost from being set incorrectly: plancost.patch
- previously it was possible to set effective_cache_size to 0, which
would then be ignored and treated as 1 at run-time, so set minimum to 1
and remove test at run-time.

Ignore that part....the run-time test is still needed, of course.

--
Best Regards, Simon Riggs

Simon Riggs <simon@2ndquadrant.com> writes:

I enclose a doc patch for the effective_cache_size parameter in
runtime.sgml: efcdoc.patch

Applied after translation into English ;-)

Also, another minor patch which prevents effective_cache_size and
random_page_cost from being set incorrectly: plancost.patch
- previously it was possible to set effective_cache_size to 0, which
would then be ignored and treated as 1 at run-time, so set minimum to 1
and remove test at run-time.

I applied the guc.c change but did not remove the run-time test, just
to be on the safe side.

- previously it was possible to set random_page_cost as a fractional
value between 0 and 1, which screws up planner estimation, so set
minimum value of 1 (i.e. random cost same as sequential cost).

Did not apply this. People sometimes use random_cost < 1 to force the
planner to pick index scans. Ideally this shouldn't be necessary...

regards, tom lane

On Thu, 2004-11-04 at 19:13, Tom Lane wrote:

Simon Riggs <simon@2ndquadrant.com> writes:

I enclose a doc patch for the effective_cache_size parameter in
runtime.sgml: efcdoc.patch

Applied after translation into English ;-)

Yes, the most significant bit often seems to get flipped in en_GB to
en_US conversions in either direction. :->

--
Best Regards, Simon Riggs