Обсуждение: GIN pending clean up is not interruptable
When a user backend (as opposed to vacuum or autoanalyze) gets burdened with cleaning up the GIN pending list, it does not call CHECK_FOR_INTERRUPTS().
Since cleaning does a lot of random IO, it can take a long time and it is not nice to be uninterruptable.
The attached patch adds an else branch to call CHECK_FOR_INTERRUPTS().
But I think we could instead just call vacuum_delay_point unconditionally. It calls CHECK_FOR_INTERRUPTS(), and if not in a throttled vacuum it does nothing else. (That is how ANALYZE handles it.)
This issue is in all branches.
Cheers,
Jeff
Вложения
On 2015-08-11 15:07:15 -0700, Jeff Janes wrote: > When a user backend (as opposed to vacuum or autoanalyze) gets burdened > with cleaning up the GIN pending list, it does not > call CHECK_FOR_INTERRUPTS(). > > Since cleaning does a lot of random IO, it can take a long time and it is > not nice to be uninterruptable. Agreed. > The attached patch adds an else branch to call CHECK_FOR_INTERRUPTS(). > > But I think we could instead just call vacuum_delay_point unconditionally. > It calls CHECK_FOR_INTERRUPTS(), and if not in a throttled vacuum it does > nothing else. (That is how ANALYZE handles it.) Hm, I find that not exactly pretty. I'd rather just add an unconditional CHECK_FOR_INTERRUPTS to the function. Greetings, Andres Freund
Andres Freund <andres@anarazel.de> writes: > On 2015-08-11 15:07:15 -0700, Jeff Janes wrote: >> The attached patch adds an else branch to call CHECK_FOR_INTERRUPTS(). >> >> But I think we could instead just call vacuum_delay_point unconditionally. >> It calls CHECK_FOR_INTERRUPTS(), and if not in a throttled vacuum it does >> nothing else. (That is how ANALYZE handles it.) > Hm, I find that not exactly pretty. I'd rather just add an unconditional > CHECK_FOR_INTERRUPTS to the function. CHECK_FOR_INTERRUPTS is very cheap. But I tend to agree that you should be using vacuum_delay_point. regards, tom lane
On Tue, Aug 11, 2015 at 5:27 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
Andres Freund <andres@anarazel.de> writes:
> On 2015-08-11 15:07:15 -0700, Jeff Janes wrote:
>> The attached patch adds an else branch to call CHECK_FOR_INTERRUPTS().
>>
>> But I think we could instead just call vacuum_delay_point unconditionally.
>> It calls CHECK_FOR_INTERRUPTS(), and if not in a throttled vacuum it does
>> nothing else. (That is how ANALYZE handles it.)
> Hm, I find that not exactly pretty. I'd rather just add an unconditional
> CHECK_FOR_INTERRUPTS to the function.
CHECK_FOR_INTERRUPTS is very cheap. But I tend to agree that you should
be using vacuum_delay_point.
Attached patch does it that way. There was also a free-standing CHECK_FOR_INTERRUPTS() which had no reason that I could see not be a vacuum_delay_point, so I changed that one as well.
With this patch, ctrl-C and 'pg_ctl stop -mf' both behave nicely.
Cheers,
Jeff
Вложения
On 2015-08-12 11:59:48 -0700, Jeff Janes wrote: > Attached patch does it that way. There was also a free-standing > CHECK_FOR_INTERRUPTS() which had no reason that I could see not be a > vacuum_delay_point, so I changed that one as well. I think we should backpatch this - any arguments against? Andres
On Thu, Sep 3, 2015 at 2:15 AM, Andres Freund <andres@anarazel.de> wrote: > On 2015-08-12 11:59:48 -0700, Jeff Janes wrote: >> Attached patch does it that way. There was also a free-standing >> CHECK_FOR_INTERRUPTS() which had no reason that I could see not be a >> vacuum_delay_point, so I changed that one as well. - if (vac_delay) - vacuum_delay_point(); + vacuum_delay_point(); If vac_delay is false, e.g., ginInsertCleanup() is called by the backend, vacuum_delay_point() should not be called. No? > I think we should backpatch this - any arguments against? +1 for backpatch. Regards, -- Fujii Masao
On 2015-09-03 12:45:34 +0900, Fujii Masao wrote: > On Thu, Sep 3, 2015 at 2:15 AM, Andres Freund <andres@anarazel.de> wrote: > > On 2015-08-12 11:59:48 -0700, Jeff Janes wrote: > >> Attached patch does it that way. There was also a free-standing > >> CHECK_FOR_INTERRUPTS() which had no reason that I could see not be a > >> vacuum_delay_point, so I changed that one as well. > > - if (vac_delay) > - vacuum_delay_point(); > + vacuum_delay_point(); > > If vac_delay is false, e.g., ginInsertCleanup() is called by the backend, > vacuum_delay_point() should not be called. No? No, that's the whole point of the change, we need a CHECK_FOR_INTERRUPTS() even when called by backends. I personally think it's rather ugly to rely on the the one in vacuum_delay_point, but Jeff and Tom think it's better, and I can live with that. Greetings, Andres Freund
On Thu, Sep 3, 2015 at 7:18 PM, Andres Freund <andres@anarazel.de> wrote: > On 2015-09-03 12:45:34 +0900, Fujii Masao wrote: >> On Thu, Sep 3, 2015 at 2:15 AM, Andres Freund <andres@anarazel.de> wrote: >> > On 2015-08-12 11:59:48 -0700, Jeff Janes wrote: >> >> Attached patch does it that way. There was also a free-standing >> >> CHECK_FOR_INTERRUPTS() which had no reason that I could see not be a >> >> vacuum_delay_point, so I changed that one as well. >> >> - if (vac_delay) >> - vacuum_delay_point(); >> + vacuum_delay_point(); >> >> If vac_delay is false, e.g., ginInsertCleanup() is called by the backend, >> vacuum_delay_point() should not be called. No? > > No, that's the whole point of the change, we need a > CHECK_FOR_INTERRUPTS() even when called by backends. I personally think > it's rather ugly to rely on the the one in vacuum_delay_point, Same here. > but Jeff > and Tom think it's better, and I can live with that. OK, probably I can live with that, too. Regards, -- Fujii Masao