| Lists: | pgsql-hackers |
|---|
| From: | Jeff Janes <jeff(dot)janes(at)gmail(dot)com> |
|---|---|
| To: | pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | effective_cache_size cannot be changed by a reload |
| Date: | 2014-03-19 17:34:36 |
| Message-ID: | CAMkU=1zTMNZsnUV6L7aMvfJZfzjKbzAtuML3N35wyYaia9MJAw@mail.gmail.com |
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| Lists: | pgsql-hackers |
In 9.4dev, if the server is started with effective_cache_size = -1, then it
cannot be changed away from that without a restart. If you change the
config file and do a reload or pg_reload_conf(), it ignores the change
without comment in the logs.
If you start the server with a value other than -1, then you can change the
value by editing the file and doing a reload. You can even change it to
-1, and then change it back away from -1 again.
It has been that way since at least 6b82f78ff95d7d4201d44359. Before that
it was broken in other ways, so I don't know what the behavior would have
been.
I don't know if bugs reports (without patches) against pre-release versions
are supposed to go to hackers or to bugs. If someone has a strong
preference, they might want to clarify this on the bug report form.
Cheers,
Jeff
| From: | Fujii Masao <masao(dot)fujii(at)gmail(dot)com> |
|---|---|
| To: | Jeff Janes <jeff(dot)janes(at)gmail(dot)com> |
| Cc: | pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: effective_cache_size cannot be changed by a reload |
| Date: | 2014-03-20 12:03:46 |
| Message-ID: | CAHGQGwGgFq+2NSjsq=XE+9MhOOeT6+u95OhqZ0sCt0vq_D1CHA@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Thu, Mar 20, 2014 at 2:34 AM, Jeff Janes <jeff(dot)janes(at)gmail(dot)com> wrote:
> In 9.4dev, if the server is started with effective_cache_size = -1, then it
> cannot be changed away from that without a restart. If you change the
> config file and do a reload or pg_reload_conf(), it ignores the change
> without comment in the logs.
>
> If you start the server with a value other than -1, then you can change the
> value by editing the file and doing a reload. You can even change it to -1,
> and then change it back away from -1 again.
I think that's a bug. Patch attached.
> I don't know if bugs reports (without patches) against pre-release versions
> are supposed to go to hackers or to bugs.
Either works at least for me.
Regards,
--
Fujii Masao
| Attachment | Content-Type | Size |
|---|---|---|
| bugfix.patch | text/x-diff | 645 bytes |
| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Fujii Masao <masao(dot)fujii(at)gmail(dot)com> |
| Cc: | Jeff Janes <jeff(dot)janes(at)gmail(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: effective_cache_size cannot be changed by a reload |
| Date: | 2014-03-20 15:35:40 |
| Message-ID: | 4809.1395329740@sss.pgh.pa.us |
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| Lists: | pgsql-hackers |
Fujii Masao <masao(dot)fujii(at)gmail(dot)com> writes:
> On Thu, Mar 20, 2014 at 2:34 AM, Jeff Janes <jeff(dot)janes(at)gmail(dot)com> wrote:
>> In 9.4dev, if the server is started with effective_cache_size = -1, then it
>> cannot be changed away from that without a restart.
> I think that's a bug. Patch attached.
PGC_S_FILE is at least as bogus as the previous choice; for one thing,
such a source setting implies there should be a file and line number
recorded.
I think PGC_S_DYNAMIC_DEFAULT is the right thing, but I've not absorbed
much caffeine yet today. Also, if that is the right thing, the section of
guc-file.l beginning at about line 284 needs to get taught about it; which
probably means that set_default_effective_cache_size needs a rethink so
that it can be applied and do something useful in that situation.
regards, tom lane