Обсуждение: resource leak in 7.2

There was a bug in 7.1.2 that was fixed in 7.1.3 that may be back in
7.2.

I downloaded 7.2 yesterday morning and started testing it.  I left some
procedures running overnight performing random updates in a table.
Looking at task manager this morning, the three backend processes are
each consuming about 1.5e6 handles.

I'd report this to the bug system but can't get there from here this
morning.

"Tom Pfau" <T.Pfau@emCrit.com> writes:
> There was a bug in 7.1.2 that was fixed in 7.1.3 that may be back in
> 7.2.
> I downloaded 7.2 yesterday morning and started testing it.  I left some
> procedures running overnight performing random updates in a table.
> Looking at task manager this morning, the three backend processes are
> each consuming about 1.5e6 handles.

I see nothing in the CVS logs to make me think that any file-handle-leakage
bug was fixed between 7.1.2 and 7.1.3; and even less to make me think
that 7.1.3 contains any fixes that weren't also applied to the 7.2 line.

You're going to have to be a great deal more specific.

            regards, tom lane

We were initially using 7.1.2.  Some overnight tests of our application
revealed that the backends were not releasing handles according to task
manager.  We upgraded to 7.1.3 and the problem went away.

My initial testing of 7.2 shows the same symptom although I don't know
that it's the same cause.  I just noted that we have seen the problem
before so that if anyone was aware of the prior problem, they might be
able to check that it hadn't been lost in the new version.  I don't know
exactly what got changed between 7.1.2 and 7.1.3 to cause the problem to
go away.

In any case, if I run my test procedure which just performs updates to a
random column of a random row of a 1000 row table, I can watch the
handle usage continue to rise on the backend process.

Looking a bit more closely now, a single process doesn't seem to cause a
problem.  Running two or more copies simultaneously causes the backends
to continuously consume handles.  If I stop one of the processes, the
other stops losing handles.

I'm attaching the test procedure.  BTW, the file it reads for data
contains a log of a vacuum session that has been reformatted slightly.
The lines are between 3 and 76 bytes.

-----Original Message-----
From: Tom Lane [mailto:tgl@sss.pgh.pa.us]
Sent: Tuesday, February 05, 2002 11:21 AM
To: Tom Pfau
Cc: pgsql-bugs@postgresql.org; pgsql-cygwin@postgresql.org
Subject: Re: [BUGS] resource leak in 7.2


"Tom Pfau" <T.Pfau@emCrit.com> writes:
> There was a bug in 7.1.2 that was fixed in 7.1.3 that may be back in
> 7.2.
> I downloaded 7.2 yesterday morning and started testing it.  I left
some
> procedures running overnight performing random updates in a table.
> Looking at task manager this morning, the three backend processes are
> each consuming about 1.5e6 handles.

I see nothing in the CVS logs to make me think that any
file-handle-leakage
bug was fixed between 7.1.2 and 7.1.3; and even less to make me think
that 7.1.3 contains any fixes that weren't also applied to the 7.2 line.

You're going to have to be a great deal more specific.

            regards, tom lane

"Tom Pfau" <T.Pfau@emCrit.com> writes:
> In any case, if I run my test procedure which just performs updates to a
> random column of a random row of a 1000 row table, I can watch the
> handle usage continue to rise on the backend process.
> Looking a bit more closely now, a single process doesn't seem to cause a
> problem.  Running two or more copies simultaneously causes the backends
> to continuously consume handles.  If I stop one of the processes, the
> other stops losing handles.

Unsurprisingly, I don't see any such problem under Unix (HPUX to be
specific, but I'd be astonished to see PG on any Unix do that,
considering that each backend manages its open files independently).

I think you must be looking at some misbehavior of the Cygwin layer.
If the problem really did go away in 7.1.3, perhaps some fix was applied
by the Cygwin packager and not contributed back to the main code base.
But it's got to be a Cygwin bug anyway; the most we could do is find
some workaround to avoid triggering it.

            regards, tom lane