postgres.git / summary / log / commit / refs

commit    75c24d0f7491f77dfbc0acdf6c18439f288353ef
Author:   Tom Lane <tgl@sss.pgh.pa.us>
Date:     Mon Apr 18 17:33:06 2016 +0000
First released in: 9.6.0, 9.2.17, 9.3.13, 9.4.8, 9.5.3

    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


[parent: 8ce8307bd4d6]