exit. Without this, operations triggered during backend exit (such as
temp table deletions) won't be counted ... which given heavy usage of
temp tables can lead to pg_autovacuum falling way behind on the need
to vacuum pg_class and pg_attribute. Per reports from Steve Crawford
and others.
even uglier than it was already :-(. Also, on Windows only, use temporary
shared memory segments instead of ordinary files to pass over critical
variable values from postmaster to child processes. Magnus Hagander
returning a NULL pointer (some callers remembered to check the return
value, but some did not -- it is safer to just bail out).
Also, cleanup pgstat.c to use elog(ERROR) rather than elog(LOG) followed
by exit().
recommend that people go get Apache's rotatelogs program. Additional
benefits are that configuration is done through GUC, rather than
externally, and that the postmaster can monitor the log rotator and
restart it after failure (though we certainly hope that won't happen
often).
Andreas Pflug, some rework by Tom Lane.
performance front, but with feature freeze upon us I think it's time to
drive a stake in the ground and say that this will be in 7.5.
Alvaro Herrera, with some help from Tom Lane.
specified in just one place and adhered to exactly, rather than just more
or less. A side effect is to increase PGSTAT_ACTIVITY_SIZE (maximum
reported query length) from 256 to nearly 1000.
begin the shutdown checkpoint; there isn't anything left for them to do,
so we may as well ensure that they shut down sooner rather than later.
Per discussion.
place of time_t, as per prior discussion. The behavior does not change
on machines without a 64-bit-int type, but on machines with one, which
is most, we are rid of the bizarre boundary behavior at the edges of
the 32-bit-time_t range (1901 and 2038). The system will now treat
times over the full supported timestamp range as being in your local
time zone. It may seem a little bizarre to consider that times in
4000 BC are PST or EST, but this is surely at least as reasonable as
propagating Gregorian calendar rules back that far.
I did not modify the format of the zic timezone database files, which
means that for the moment the system will not know about daylight-savings
periods outside the range 1901-2038. Given the way the files are set up,
it's not a simple decision like 'widen to 64 bits'; we have to actually
think about the range of years that need to be supported. We should
probably inquire what the plans of the upstream zic people are before
making any decisions of our own.
than being random pieces of other files. Give bgwriter responsibility
for all checkpoint activity (other than a post-recovery checkpoint);
so this child process absorbs the functionality of the former transient
checkpoint and shutdown subprocesses. While at it, create an actual
include file for postmaster.c, which for some reason never had its own
file before.
about a third, make it work on non-Windows platforms again. (But perhaps
I broke the WIN32 code, since I have no way to test that.) Fold all the
paths that fork postmaster child processes to go through the single
routine SubPostmasterMain, which takes care of resurrecting the state that
would normally be inherited from the postmaster (including GUC variables).
Clean up some places where there's no particularly good reason for the
EXEC and non-EXEC cases to work differently. Take care of one or two
FIXMEs that remained in the code.
* removed a few redundant defines
* get_user_name safe under win32
* rationalized pipe read EOF for win32 (UPDATED PATCH USED)
* changed all backend instances of sleep() to pg_usleep
- except for the SLEEP_ON_ASSERT in assert.c, as it would exceed a
32-bit long [Note to patcher: If a SLEEP_ON_ASSERT of 2000 seconds is
acceptable, please replace with pg_usleep(2000000000L)]
I added a comment to that part of the code:
/*
* It would be nice to use pg_usleep() here, but only does 2000 sec
* or 33 minutes, which seems too short.
*/
sleep(1000000);
Claudio Natoli
It works on the principle of turning sockets into non-blocking, and then
emulate blocking behaviour on top of that, while allowing signals to
run. Signals are now implemented using an event instead of APCs, thus
getting rid of the issue of APCs not being compatible with "old style"
sockets functions.
It also moves the win32 specific code away from pqsignal.h/c into
port/win32, and also removes the "thread style workaround" of the APC
issue previously in place.
In order to make things work, a few things are also changed in pgstat.c:
1) There is now a separate pipe to the collector and the bufferer. This
is required because the pipe will otherwise only be signalled in one of
the processes when the postmaster goes down. The MS winsock code for
select() must have some kind of workaround for this behaviour, but I
have found no stable way of doing that. You really are not supposed to
use the same socket from more than one process (unless you use
WSADuplicateSocket(), in which case the docs specifically say that only
one will be flagged).
2) The check for "postmaster death" is moved into a separate select()
call after the main loop. The previous behaviour select():ed on the
postmaster pipe, while later explicitly saying "we do NOT check for
postmaster exit inside the loop".
The issue was that the code relies on the same select() call seeing both
the postmaster pipe *and* the pgstat pipe go away. This does not always
happen, and it appears that useing WSAEventSelect() makes it even more
common that it does not.
Since it's only called when the process exits, I don't think using a
separate select() call will have any significant impact on how the stats
collector works.
Magnus Hagander
initialization of stats process under EXEC_BACKEND.
[A cleaner, rationalized approach to stat/backend/SSDataBase child
processes under EXEC_BACKEND is on my TODO list. However this patch
takes care of immediate concerns (ie. stats test now passes under
win32)]
Claudio Natoli
whereToSendOutput instead because they are really inquiring about
the correct client communication protocol. Update some comments.
This is pointing towards supporting regular FE/BE client protocol
in a standalone backend, per discussion a month or so back.
PostmasterPid variable, which gets set (early) in PostmasterMain
getppid would not be the postmaster?
[fork/exec] Implements processCancelRequest by keeping an array of
pid/cancel_key structs in shared mem
[fork/exec] Moves AttachSharedMemoryAndSemaphores call for backends into
SubPostmasterMain
[win32] Implements reaper/waitpid by keeping an arrays of children
pids,handles in postmaster local mem
- this item is largely untested, for reasons which should be
obvious, but appears sound
[win32/all] Added extern for pgpipe in Win32 case, and changed the second
pipe call (which seems to have been missed earlier) to pgpipe
[win32] #define'd ftruncate to chsize in the Win32 case
[win32] PG_USLEEP for Win32 has a misplaced paren. Fixed.
[win32] DLLIMPORT handling for MingW case
Claudio Natoli
BackendFork/SSDataBase/pgstat) startup, to allow fork/exec calls to
closely mimic (the soon to be provided) Win32 CreateProcess equivalent
calls.
Claudio Natoli