Hello,
>Updated patches addressing all those things are attached.
Below are some performance numbers using latest patch 20141219_fpw_compression_v9 . Compression looks promising with reduced impact on CPU usage, tps and runtime.
pgbench command : pgbench -c 16 -j 16 -r -t 250000 -M prepared
To ensure that data is not highly compressible, empty filler columns were altered using
alter table pgbench_accounts alter column filler type text using
gen_random_uuid()::text
checkpoint_segments = 1024
checkpoint_timeout = 5min
fsync = on
Compression On Off
WAL generated 24558983188(~24.56 GB) 35931217248 (~ 35.93GB)
Runtime 5987.0 s 5825.0 s
TPS tps = 668.05 tps = 686.69
Latency average 23.935 ms 23.211 ms
Latency stddev 80.619 ms 80.141 ms
CPU usage(user) 916.64s 614.76s
CPU usage(system) 54.96s 64.14s
IO(average writes to disk) 10.43 MB . 12.5 MB
IO(total writes to disk) 64268.94 MB 72920 MB
Reduction in WAL is around 32 %. Reduction in total IO writes to disk is around 12%. Impact on runtime , tps and latency is very less.
CPU usage when compression is on is increased by 49% which is lesser as compared to earlier measurements.
Server specifications:
Processors:Intel® Xeon ® Processor E5-2650 (2 GHz, 8C/16T, 20 MB) * 2 nos
RAM: 32GB
Disk : HDD 450GB 10K Hot Plug 2.5-inch SAS HDD * 8 nos
1 x 450 GB SAS HDD, 2.5-inch, 6Gb/s, 10,000 rpm
Thank you,
Rahila Syed
