Re: Article about PostgreSQL and RAID in Brazil - Mailing list pgsql-performance

From Qing Zhao
Subject Re: Article about PostgreSQL and RAID in Brazil
Date
Msg-id 224B107D-0821-11D9-B278-000A95AB8896@supplyfx.com
Whole thread Raw
In response to Re: Article about PostgreSQL and RAID in Brazil  (Josh Berkus <josh@agliodbs.com>)
Responses Re: Question about PG on OSX
List pgsql-performance
Hi, there,

I am running PostgreSQL 7.3.4 on MAC OS X G5 with dual processors and
8GB memory. The shared buffer was set as 512MB.

The database has been running great until about 10 days ago when our
developers decided to add some indexes to some tables to speed up
certain uploading ops.

Now the CPU usage reaches 100% constantly when there are a few users
accessing their information by SELECT tables in databases. If I REINEX
all the indexes, the database performance improves a bit but before
long,
it goes back to bad again.

My suspicion is that since  now a few indexes are added, every ops are
run by PostgreSQL with the indexes being used when calculating cost.
This leads to the downgrade of performance.

What do you think of this? What is the possible solution?

Thanks!

Qing

The following is the output from TOP command:

Processes:  92 total, 4 running, 88 sleeping... 180 threads
13:09:18
Load Avg:  2.81, 2.73, 2.50     CPU usage:  95.2% user, 4.8% sys, 0.0%
idle
SharedLibs: num =  116, resident = 11.5M code, 1.66M data, 4.08M
LinkEdit
MemRegions: num = 12132, resident =  148M + 2.82M private,  403M shared
PhysMem:   435M wired, 5.04G active, 2.22G inactive, 7.69G used,  316M
free
VM: 32.7G + 81.5M   5281127(13) pageins, 8544145(0) pageouts

   PID COMMAND      %CPU   TIME   #TH #PRTS #MREGS RPRVT  RSHRD  RSIZE
VSIZE
27314 postgres    92.2%  2:14.75   1     9    49  12.8M+  396M  75.0M+
849M
26099 postgres    91.1% 19:28.04   1     9    67  15.9M+  396M   298M+
850M
24754 top          2.8%  4:48.33   1    29    26   272K   404K   648K
27.1M
     0 kernel_tas   1.9%  2:12:05  40     2  8476  67.1M     0K   281M
1.03G
   294 hwmond       0.5%  2:26:34   8    75    57   240K   544K  1.09M
31.0M
   347 lookupd      0.3%  1:52:28   2    35    73  3.05M   648K  3.14M
33.6M
    89 configd      0.1% 53:05.16   3   126   151   304K   644K   832K
29.2M
26774 servermgrd   0.1%  0:02.93   1    10    40   344K- 1.17M+ 1.86M
28.2M
   170 coreservic   0.1%  0:09.04   1    40    93   152K   532K  2.64M
28.5M
   223 DirectoryS   0.1% 19:42.47   8    84   135   880K+ 1.44M  4.60M+
37.1M+
   125 dynamic_pa   0.0%  0:26.79   1    12    17    16K   292K    28K
17.7M
    87 kextd        0.0%  0:01.23   2    17    21     0K   292K    36K
28.2M
   122 update       0.0% 14:27.71   1     9    15    16K   300K    44K
17.6M
     1 init         0.0%  0:00.03   1    12    16    28K   320K    76K
17.6M
     2 mach_init    0.0%  3:36.18   2    95    18    76K   320K   148K
18.2M
    81 syslogd      0.0%  0:19.96   1    10    17    96K   320K   148K
17.7M





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