From 75c24d0f7491f77dfbc0acdf6c18439f288353ef Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Mon, 18 Apr 2016 13:33:06 -0400 Subject: [PATCH] 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. --- src/include/pg_config_manual.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index ef895211da5..8d5a3783876 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -57,7 +57,7 @@ * may improve performance, but supplying a real spinlock implementation is * probably far better. */ -#define NUM_SPINLOCK_SEMAPHORES 1024 +#define NUM_SPINLOCK_SEMAPHORES 128 /* * When we have neither spinlocks nor atomic operations support we're