From: Tom Lane Date: Mon, 18 Apr 2016 17:33:07 +0000 (-0400) Subject: Further reduce the number of semaphores used under --disable-spinlocks. X-Git-Tag: REL9_2_17~19 X-Git-Url: http://git.postgresql.org/gitweb/?a=commitdiff_plain;h=b24f7e2800be7a5d9c29677b8ef35f61c925d0d4;p=postgresql.git Further reduce the number of semaphores used under --disable-spinlocks. Per discussion, there doesn't seem to be much value in having NUM_SPINLOCK_SEMAPHORES set to 1024: under any scenario where you are running more than a few backends concurrently, you really had better have a real spinlock implementation if you want tolerable performance. And 1024 semaphores is a sizable fraction of the system-wide SysV semaphore limit on many platforms. Therefore, reduce this setting's default value to 128 to make it less likely to cause out-of-semaphores problems. --- diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index 5e2ae6f88e7..00b381ea88a 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -62,7 +62,7 @@ * may improve performance, but supplying a real spinlock implementation is * probably far better. */ -#define NUM_SPINLOCK_SEMAPHORES 1024 +#define NUM_SPINLOCK_SEMAPHORES 128 /* * Define this if you want to allow the lo_import and lo_export SQL