On 07/01/2014 01:08 PM, Andres Freund wrote:
Hi,
Over at -performance Mark Kirkwood tested a recent version of this
(http://archives.postgresql.org/message-id/53B283F3.7020005%40catalyst.net.nz)
. I thought it's interesting to add the numbers to this thread:
Test: pgbench
Options: scale 500
read only
Os: Ubuntu 14.04
Pg: 9.3.4
Pg Options:
max_connections = 200
shared_buffers = 10GB
maintenance_work_mem = 1GB
effective_io_concurrency = 10
wal_buffers = 32MB
checkpoint_segments = 192
checkpoint_completion_target = 0.8
Results
Clients | 9.3 tps 32 cores | 9.3 tps 60 cores
--------+------------------+-----------------
6 | 70400 | 71028
12 | 98918 | 129140
24 | 230345 | 240631
48 | 324042 | 409510
96 | 346929 | 120464
192 | 312621 | 92663
So we have anti scaling with 60 cores as we increase the client connections.
Ouch! A level of urgency led to trying out Andres's 'rwlock' 9.4 branch [1]
- cherry picking the last 5 commits into 9.4 branch and building a package
from that and retesting:
Clients | 9.4 tps 60 cores (rwlock)
--------+--------------------------
6 | 70189
12 | 128894
24 | 233542
48 | 422754
96 | 590796
192 | 630672
Now, this is a bit of a skewed comparison due to 9.4 vs. 9.3 but still
interesting.
It looks like the issue I reported here:
http://www.postgresql.org/message-id/5190e17b.9060...@vmware.com
fixed by this commit:
http://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=b03d196be055450c7260749f17347c2d066b4254.
So, definitely need to compare plain 9.4 vs patched 9.4, not 9.3.
- Heikki
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