Re: Do we need pre-allocate WAL files during end-of-recovery checkpoint?
| От | SATYANARAYANA NARLAPURAM |
|---|---|
| Тема | Re: Do we need pre-allocate WAL files during end-of-recovery checkpoint? |
| Дата | |
| Msg-id | CAHg+QDdzqphWqo_ijFiDE+XLdKuNG=BLuLHfOK+fXActKkVOJw@mail.gmail.com обсуждение исходный текст |
| Ответ на | Do we need pre-allocate WAL files during end-of-recovery checkpoint? (Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>) |
| Ответы |
Re: Do we need pre-allocate WAL files during end-of-recovery checkpoint?
Re: Do we need pre-allocate WAL files during end-of-recovery checkpoint? |
| Список | pgsql-hackers |
If the segment size is 16MB it shouldn't take much time but higher segment values this can be a problem. But again, the current segment has to be filled 75% to precreate new one. I am not sure how much we gain. Do you have some numbers with different segment sizes?
On Mon, Dec 6, 2021 at 4:51 AM Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com> wrote:
Hi,
The function PreallocXlogFiles doesn't get called during
end-of-recovery checkpoint in CreateCheckPoint, see [1]. The server
becomes operational after the end-of-recovery checkpoint and may need
WAL files. However, I'm not sure how beneficial it is going to be if
the WAL is pre-allocated (as PreallocXlogFiles just allocates only 1
extra WAL file).
Thoughts?
[1]
/*
* An end-of-recovery checkpoint is really a shutdown checkpoint, just
* issued at a different time.
*/
if (flags & (CHECKPOINT_IS_SHUTDOWN | CHECKPOINT_END_OF_RECOVERY))
shutdown = true;
else
shutdown = false;
/*
* Make more log segments if needed. (Do this after recycling old log
* segments, since that may supply some of the needed files.)
*/
if (!shutdown)
PreallocXlogFiles(recptr, checkPoint.ThisTimeLineID);
Regards,
Bharath Rupireddy.
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