| Lists: | pgsql-patches |
|---|
| From: | Simon Riggs <simon(at)2ndquadrant(dot)com> |
|---|---|
| To: | pgsql-patches(at)postgresql(dot)org |
| Subject: | effective_cache_size patch |
| Date: | 2004-11-04 16:37:49 |
| Message-ID: | 1099586269.4320.469.camel@localhost.localdomain |
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| Lists: | pgsql-patches |
I enclose a doc patch for the effective_cache_size parameter in
runtime.sgml: efcdoc.patch
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.
- 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).
--
Best Regards, Simon Riggs
| Attachment | Content-Type | Size |
|---|---|---|
| efcdoc.patch | text/x-patch | 1.9 KB |
| plancost.patch | text/x-patch | 1.9 KB |
| From: | Simon Riggs <simon(at)2ndquadrant(dot)com> |
|---|---|
| To: | pgsql-patches(at)postgresql(dot)org |
| Subject: | Re: effective_cache_size patch |
| Date: | 2004-11-04 18:57:29 |
| Message-ID: | 1099594649.4320.649.camel@localhost.localdomain |
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| Lists: | pgsql-patches |
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
| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Simon Riggs <simon(at)2ndquadrant(dot)com> |
| Cc: | pgsql-patches(at)postgresql(dot)org |
| Subject: | Re: effective_cache_size patch |
| Date: | 2004-11-04 19:13:05 |
| Message-ID: | 27927.1099595585@sss.pgh.pa.us |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Lists: | pgsql-patches |
Simon Riggs <simon(at)2ndquadrant(dot)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
| From: | Simon Riggs <simon(at)2ndquadrant(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | pgsql-patches(at)postgresql(dot)org |
| Subject: | Re: effective_cache_size patch |
| Date: | 2004-11-04 20:48:06 |
| Message-ID: | 1099601285.5682.11.camel@localhost.localdomain |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Lists: | pgsql-patches |
On Thu, 2004-11-04 at 19:13, Tom Lane wrote:
> Simon Riggs <simon(at)2ndquadrant(dot)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