From: | heikki(at)postgresql(dot)org (Heikki Linnakangas) |
---|---|
To: | pgsql-committers(at)postgresql(dot)org |
Subject: | pgsql: Introduce latches. |
Date: | 2010-09-11 15:48:04 |
Message-ID: | 20100911154804.DC0187541E2@cvs.postgresql.org |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-committers pgsql-hackers |
Log Message:
-----------
Introduce latches. A latch is a boolean variable, with the capability to
wait until it is set. Latches can be used to reliably wait until a signal
arrives, which is hard otherwise because signals don't interrupt select()
on some platforms, and even when they do, there's race conditions.
On Unix, latches use the so called self-pipe trick under the covers to
implement the sleep until the latch is set, without race conditions. On
Windows, Windows events are used.
Use the new latch abstraction to sleep in walsender, so that as soon as
a transaction finishes, walsender is woken up to immediately send the WAL
to the standby. This reduces the latency between master and standby, which
is good.
Preliminary work by Fujii Masao. The latch implementation is by me, with
helpful comments from many people.
Modified Files:
--------------
pgsql:
configure (r1.685 -> r1.686)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/configure?r1=1.685&r2=1.686)
configure.in (r1.633 -> r1.634)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/configure.in?r1=1.633&r2=1.634)
pgsql/src/backend/access/transam:
twophase.c (r1.63 -> r1.64)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/transam/twophase.c?r1=1.63&r2=1.64)
xact.c (r1.298 -> r1.299)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/transam/xact.c?r1=1.298&r2=1.299)
pgsql/src/backend/port:
Makefile (r1.28 -> r1.29)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/port/Makefile?r1=1.28&r2=1.29)
pgsql/src/backend/replication:
walsender.c (r1.29 -> r1.30)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/replication/walsender.c?r1=1.29&r2=1.30)
pgsql/src/backend/storage/ipc:
ipci.c (r1.104 -> r1.105)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/storage/ipc/ipci.c?r1=1.104&r2=1.105)
procsignal.c (r1.7 -> r1.8)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/storage/ipc/procsignal.c?r1=1.7&r2=1.8)
pgsql/src/include/replication:
walsender.h (r1.4 -> r1.5)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/replication/walsender.h?r1=1.4&r2=1.5)
pgsql/src/tools/msvc:
Mkvcbuild.pm (r1.59 -> r1.60)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/tools/msvc/Mkvcbuild.pm?r1=1.59&r2=1.60)
Added Files:
-----------
pgsql/src/backend/port:
unix_latch.c (r1.1)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/port/unix_latch.c?rev=1.1&content-type=text/x-cvsweb-markup)
win32_latch.c (r1.1)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/port/win32_latch.c?rev=1.1&content-type=text/x-cvsweb-markup)
pgsql/src/include/storage:
latch.h (r1.1)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/storage/latch.h?rev=1.1&content-type=text/x-cvsweb-markup)
From | Date | Subject | |
---|---|---|---|
Next Message | Heikki Linnakangas | 2010-09-11 16:26:04 | pgsql: Add missing #includes, needed on some platforms. |
Previous Message | User Doudou586 | 2010-09-11 14:08:13 | press - pr: Release date changed. |
From | Date | Subject | |
---|---|---|---|
Next Message | Heikki Linnakangas | 2010-09-11 16:15:52 | Re: Interruptible sleeps (was Re: CommitFest 2009-07: Yay, Kevin! Thanks, reviewers!) |
Previous Message | Tom Lane | 2010-09-11 15:02:45 | Re: Interruptible sleeps (was Re: CommitFest 2009-07: Yay, Kevin! Thanks, reviewers!) |