What happens if checkpoint haven't completed until the next checkpoint interval or max_wal_size?

Started by Mohammad Sherafatalmost 7 years ago5 messages
#1Mohammad Sherafat
mhdsherafat@chmail.ir

In the name of god!

Hi,

What happens if checkpoint haven't completed until the next checkpoint
interval or max_wal_size?

thanks,

regards, Mohammad Sherafat.

#2Laurenz Albe
laurenz.albe@cybertec.at
In reply to: Mohammad Sherafat (#1)
Re: What happens if checkpoint haven't completed until the next checkpoint interval or max_wal_size?

Mohammad Sherafat wrote:

In the name of god!

It is not considered good style to hurt people's religious feelings
by using the name of god in vain.

What happens if checkpoint haven't completed until the next checkpoint
interval or max_wal_size?

Then you have two checkpoints active at the same time.

Yours,
Laurenz Albe

#3Robert Haas
robertmhaas@gmail.com
In reply to: Laurenz Albe (#2)
Re: What happens if checkpoint haven't completed until the next checkpoint interval or max_wal_size?

On Mon, Feb 4, 2019 at 2:50 PM Laurenz Albe <laurenz.albe@cybertec.at>
wrote:

Mohammad Sherafat wrote:

In the name of god!

It is not considered good style to hurt people's religious feelings
by using the name of god in vain.

I agree but...

What happens if checkpoint haven't completed until the next checkpoint

interval or max_wal_size?

Then you have two checkpoints active at the same time.

...not about this part. I think the next checkpoint just doesn't start
until the one already in progress completes.

...Robert

--

Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

#4Michael Paquier
michael@paquier.xyz
In reply to: Robert Haas (#3)
Re: What happens if checkpoint haven't completed until the next checkpoint interval or max_wal_size?

On Tue, Feb 05, 2019 at 04:11:55PM +0530, Robert Haas wrote:

...not about this part. I think the next checkpoint just doesn't start
until the one already in progress completes.

Yes, the requests are communicated from any backends to the
checkpointer with shared memory (see ckpt_flags in RequestCheckpoint),
and the backend signals the checkpointer to do the work, still it
won't do the work until the checkpoint currently running finishes.
--
Michael

#5Kyotaro HORIGUCHI
horiguchi.kyotaro@lab.ntt.co.jp
In reply to: Michael Paquier (#4)
Re: What happens if checkpoint haven't completed until the next checkpoint interval or max_wal_size?

At Tue, 5 Feb 2019 20:42:59 +0900, Michael Paquier <michael@paquier.xyz> wrote in <20190205114259.GH1882@paquier.xyz>

On Tue, Feb 05, 2019 at 04:11:55PM +0530, Robert Haas wrote:

...not about this part. I think the next checkpoint just doesn't start
until the one already in progress completes.

Yes, the requests are communicated from any backends to the
checkpointer with shared memory (see ckpt_flags in RequestCheckpoint),
and the backend signals the checkpointer to do the work, still it
won't do the work until the checkpoint currently running finishes.

And, requests for checkpoints are not queued. Multiple checkpoint
requests (both automatically and manually) made during a
checkpoint are finished at once at the end of the running
checkpoint.

regards.

--
Kyotaro Horiguchi
NTT Open Source Software Center