shared_buffers and shmmax

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hi,
I'm trying to understand what the documentation means by bytes per increment, what is the increment supposed to be bytes, MB, or Kb.  I have my shared_buffers set to 577 MB(4 instances) and I'm multiplying by 8400 bytes.  I would think I would want to keep everything in bytes and not mulitply bytes times MB, but this is what table 17-2 implies.  If I convert 577 to bytes and multiply, my calculator goes exponential on me. I'm going through this table and adding up to see what my shmmax should be (it's 7.5 GB) out of a total memory of 16 GB with 1000 max_connections right now.  What should I use as the "increment" value in regards to shared buffers, 577, 590848 or 605028352 ?
 
a) 577 MB (This seems too small)
b) 590,848 Kb (this seems just right)
c) 605,028,352 bytes  (this seems too big, I hope it's not c)
 
Thanks,
~DjK
 
Table 17-2. Configuration parameters affecting PostgreSQL's shared memory usage
Name Approximate multiplier (bytes per increment) as of 8.3
max_connections 1800 + 270 * max_locks_per_transaction
autovacuum_max_workers 1800 + 270 * max_locks_per_transaction
max_prepared_transactions 770 + 270 * max_locks_per_transaction
shared_buffers 8400 (assuming 8 kB BLCKSZ)
wal_buffers 8200 (assuming 8 kB XLOG_BLCKSZ)
max_fsm_relations 70
max_fsm_pages 6
Fixed space requirements 770 kB



Stay in touch when you're away with Windows Live Messenger. IM anytime you're online.

[Index of Archives]     [KVM ARM]     [KVM ia64]     [KVM ppc]     [Virtualization Tools]     [Spice Development]     [Libvirt]     [Libvirt Users]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite Questions]     [Linux Kernel]     [Linux SCSI]     [XFree86]

  Powered by Linux