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Hi, One of our PG server is experiencing extreme slowness and
there are hundreds of SELECTS building up. I am not sure if heavy context
switching is the cause of this or something else is causing it. Is this pretty much the final word on this issue? http://archives.postgresql.org/pgsql-performance/2004-04/msg00249.php procs
memory
swap
io
system cpu r b swpd
free buff cache si
so bi bo in cs us
sy id wa 2 0 20 2860544 124816
8042544 0 0
0 0 0 0
0 0 0 0 2 0 20 2860376 124816
8042552 0 0
0 24 157 115322 13 10 76 0 3 0 20 2860364 124840
8042540 0 0
0 228 172 120003 12 10 77 0 2 0 20 2860364 124840
8042540 0 0
0 20 158 118816 15 10 75 0 2 0 20 2860080 124840
8042540 0 0
0 10 152 117858 12 11 77 0 1 0 20 2860080 124848
8042572 0 0
0 210 202 114724 14 10 76 0 2 0 20 2860080 124848
8042572 0 0
0 20 169 114843 13 10 77 0 3 0 20 2859908 124860
8042576 0 0
0 188 180 115134 14 11 75 0 3 0 20 2859848 124860
8042576 0 0
0 20 173 113470 13 10 77 0 2 0 20 2859836 124860
8042576 0 0
0 10 157 112839 14 11 75 0 The system seems to be fine on iowait/memory side, except
the CPU being busy with the CS. Here’s the top output: 11:54:57 up 59 days, 14:11, 2 users, load
average: 1.13, 1.66, 1.52 282 processes: 281 sleeping, 1 running, 0 zombie, 0 stopped CPU states: cpu
user nice system irq
softirq iowait idle
total 13.8% 0.0% 9.7%
0.0% 0.0% 0.0% 76.2%
cpu00 12.3% 0.0% 10.5%
0.0% 0.0% 0.1% 76.8%
cpu01 12.1% 0.0%
6.1% 0.0% 0.0%
0.1% 81.5%
cpu02 10.9% 0.0%
9.1% 0.0% 0.0%
0.0% 79.9% cpu03
19.4% 0.0% 14.9%
0.0% 0.0% 0.0% 65.6%
cpu04 13.9% 0.0% 11.1%
0.0% 0.0% 0.0% 74.9%
cpu05 14.9% 0.0%
9.1% 0.0% 0.0%
0.0% 75.9%
cpu06 12.9% 0.0% 8.9% 0.0%
0.0% 0.0% 78.1%
cpu07 14.3% 0.0%
8.1% 0.0% 0.1%
0.0% 77.3% Mem: 12081720k av, 9273304k used, 2808416k
free, 0k shrd, 126048k buff
4686808k actv, 3211872k in_d, 170240k in_c Swap: 4096532k av, 20k used,
4096512k
free
8044072k cached PostgreSQL 7.4.7 on i686-redhat-linux-gnu Red Hat Enterprise Linux AS release 3 (Taroon Update 5) Linux vl-pe6650-004 2.4.21-32.0.1.ELsmp This is a Dell Quad XEON. Hyperthreading is turned on, and I
am planning to turn it off as soon as I get a chance to bring it down. WAL is on separate drives from the OS and database. Appreciate any inputs please…. Thanks, |
