| Lists: | pgsql-committerspgsql-hackers |
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| From: | Peter Eisentraut <peter_e(at)gmx(dot)net> |
|---|---|
| To: | pgsql-committers(at)postgresql(dot)org |
| Subject: | pgsql: Use latch instead of select() in walreceiver |
| Date: | 2016-12-02 01:29:49 |
| Message-ID: | [email protected] |
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| Lists: | pgsql-committers pgsql-hackers |
Use latch instead of select() in walreceiver
Replace use of poll()/select() by WaitLatchOrSocket(), which is more
portable and flexible.
Also change walreceiver to use its procLatch instead of a custom latch.
From: Petr Jelinek <petr(at)2ndquadrant(dot)com>
Branch
------
master
Modified Files
--------------
src/backend/postmaster/pgstat.c | 3 +
.../libpqwalreceiver/libpqwalreceiver.c | 101 +++++----------------
src/backend/replication/walreceiver.c | 18 ++--
src/backend/replication/walreceiverfuncs.c | 6 +-
src/include/pgstat.h | 1 +
src/include/replication/walreceiver.h | 3 +-
6 files changed, 43 insertions(+), 89 deletions(-)
| From: | Michael Paquier <michael(dot)paquier(at)gmail(dot)com> |
|---|---|
| To: | Peter Eisentraut <peter_e(at)gmx(dot)net> |
| Cc: | pgsql-committers(at)postgresql(dot)org |
| Subject: | Re: pgsql: Use latch instead of select() in walreceiver |
| Date: | 2016-12-02 01:50:30 |
| Message-ID: | CAB7nPqRA_cO_r_PLmRvFUtpvrTUeeBooXst1+oDecTPmTckp5A@mail.gmail.com |
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On Fri, Dec 2, 2016 at 10:29 AM, Peter Eisentraut <peter_e(at)gmx(dot)net> wrote:
> Use latch instead of select() in walreceiver
>
> Replace use of poll()/select() by WaitLatchOrSocket(), which is more
> portable and flexible.
>
> Also change walreceiver to use its procLatch instead of a custom latch.
>
> From: Petr Jelinek <petr(at)2ndquadrant(dot)com>
+ ResetLatch(&MyProc->procLatch);
+ rc = WaitLatchOrSocket(&MyProc->procLatch,
+ WL_POSTMASTER_DEATH | WL_SOCKET_READABLE |
+ WL_LATCH_SET,
+ PQsocket(streamConn),
+ 0,
+ WAIT_EVENT_LIBPQWALRECEIVER_READ);
+ if (rc & WL_POSTMASTER_DEATH)
+ exit(1);
Hmm. We have always been very careful about not leaving immediately
from libpqwalreceiver.c which is an independent shared library so as
the WAL receiver can take cleanup actions. See here for more details:
https://www.postgresql.org/message-id/CAEepm=0hg_FX7kdUhosTpJ_kPsUZw6k-7nuQNy-dGAOaetn_tA@mail.gmail.com
--
Michael
| From: | Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com> |
|---|---|
| To: | Michael Paquier <michael(dot)paquier(at)gmail(dot)com> |
| Cc: | pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: [COMMITTERS] pgsql: Use latch instead of select() in walreceiver |
| Date: | 2016-12-04 01:16:12 |
| Message-ID: | [email protected] |
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| Lists: | pgsql-committers pgsql-hackers |
On 12/1/16 8:50 PM, Michael Paquier wrote:
> + if (rc & WL_POSTMASTER_DEATH)
> + exit(1);
> Hmm. We have always been very careful about not leaving immediately
> from libpqwalreceiver.c which is an independent shared library so as
> the WAL receiver can take cleanup actions. See here for more details:
> https://www.postgresql.org/message-id/CAEepm=0hg_FX7kdUhosTpJ_kPsUZw6k-7nuQNy-dGAOaetn_tA@mail.gmail.com
walreceiver.c does the same thing. The message you pointed out is not
exactly clear why that would be wrong.
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services