From: | Horak Daniel <horak(at)mmp(dot)plzen-city(dot)cz> |
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To: | "'Tom Lane'" <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | "'pgsql-hackers(at)postgreSQL(dot)org'" <pgsql-hackers(at)postgreSQL(dot)org> |
Subject: | RE: [HACKERS] backend freezeing on win32 fixed (I hope ;-) ) |
Date: | 1999-08-17 14:26:12 |
Message-ID: | 2E7F82FAC1FCD2118E1500A024B3BF907DED41@exchange.mmp.plzen-city.cz |
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Lists: | pgsql-hackers |
> How do you know it has no negative effects? The problem that it was
> intended to fix only showed up with large numbers of backends
> (ie, more
> than the system limit on number of semaphores, which is depressingly
> small on many old-line Unixes). Perhaps cygipc has no limit on number
> of semaphores, or perhaps it tries to be a faithful imitation
> of SysV ;-)
> Have you checked?
There is a static limit on the max number of semaphores, it can cause the
same problems as on Unix.
this is part of sys/sem.h:
#define SEMMNI 128 /* ? max # of semaphore identifiers */
#define SEMMSL 32 /* <= 512 max num of semaphores per id */
?? should be 32 sems per id (DH)
#define SEMMNS (SEMMNI*SEMMSL) /* ? max # of semaphores in system */
#define SEMOPM 32 /* ~ 100 max num of ops per semop call */
#define SEMVMX 32767 /* semaphore maximum value */
But I have thought no negative effects on other ports.
Dan
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