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Hi PostgreSQL developers!

Jacek Drobiecki recently sent me a patch which stops postgresql to
actively violate the system limit of maximum open files
(RLIMIT_NOFILE) in src/backend/storage/file/fd.c, function
count_usable_fds().=20

This avoids irritating kernel logs (if system overstep violations are
enabled) and also the grsecurity alert when starting PostgreSQL.

Can you please adopt this patch?

Currently the modifications are only enabled when postgresql is
compiled with -DCHECK_RLIMIT_NOFILE. Of course you can also use it
unconditionally.

Thanks for considering and have a nice day!

Martin

--=20
Martin Pitt Debian GNU/Linux Developer
martin (AT) piware (DOT) de mpitt (AT) debian (DOT) org
http://www.piware.de http://www.debian.org

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diff -ruN postgresql-7.4.2-old/src/backend/storage/file/fd.c postgresql-7.4=
..2/src/backend/storage/file/fd.c
--- postgresql-7.4.2-old/src/backend/storage/file/fd.c 2004-02-24 00:03:43.=
000000000 +0100
+++ postgresql-7.4.2/src/backend/storage/file/fd.c 2004-05-17 13:31:44.0000=
00000 +0200
@@ -50,6 +50,9 @@
#include "storage/fd.h"
#include "storage/ipc.h"
=20
+#ifdef CHECK_RLIMIT_NOFILE
+#include <sys/resource.h>
+#endif
=20
/* Filename components for OpenTemporaryFile */
#define PG_TEMP_FILES_DIR "pgsql_tmp"
@@ -272,15 +275,28 @@
int used =3D 0;
int highestfd =3D 0;
int j;
+#ifdef CHECK_RLIMIT_NOFILE
+ struct rlimit rlim;
+#endif
=20
size =3D 1024;
fd =3D (int *) palloc(size * sizeof(int));
=20
+#ifdef CHECK_RLIMIT_NOFILE
+ getrlimit(RLIMIT_NOFILE, &rlim);
+#endif
+
/* dup until failure ... */
for (;
{
int thisfd;
=20
+#ifdef CHECK_RLIMIT_NOFILE
+ /* Don't go beyond RLIMIT_NOFILE */
+ if (highestfd >=3D rlim.rlim_cur - 1)
+ break;
+#endif
+
thisfd =3D dup(0);
if (thisfd < 0)
{

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We have already fixed this in CVS and the fix will be in 7.5:

revision 1.107
date: 2004/02/23 20:45:59; author: tgl; state: Exp; lines: +145 -88
Do a direct probe during postmaster startup to determine the maximum
number of openable files and the number already opened. This eliminates
depending on sysconf(_SC_OPEN_MAX), and allows much saner behavior on
platforms where open-file slots are used up by semaphores.


---------------------------------------------------------------------------

Martin Pitt wrote:
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--
Bruce Momjian | http://candle.pha.pa.us
pgman (AT) candle (DOT) pha.pa.us | (610) 359-1001
+ If your life is a hard drive, | 13 Roberts Road
+ Christ can be your backup. | Newtown Square, Pennsylvania 19073

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Bruce Momjian <pgman (AT) candle (DOT) pha.pa.us> writes:
I don't think that the previous changes address what the complainant
seems to really want, viz not even *try* to exceed RLIMIT_NOFILE.

However the patch certainly must be rejected since (a) it appears
unaware of the post-7.4 work in this area, (b) it has not been made
portable (eg, it will fail to compile on machines without getrlimit),
and (c) we do not like patches that add random manual configuration
symbols to the code ... especially undocumented ones.

If this issue seems important to you then please rework the patch to be
up-to-date and properly autoconfiscated, and resubmit.

regards, tom lane

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TIP 7: don't forget to increase your free space map settings