RE: Oracle & pagefaults (solaris)
- From: "Johnson, William L (TEIS)" <WLJohnson@xxxxxx>
- To: "przemolicc@xxxxxxxxx" <przemolicc@xxxxxxxxx>, "oracle-l@xxxxxxxxxxxxx" <oracle-l@xxxxxxxxxxxxx>
- Date: Mon, 13 Aug 2012 10:35:17 -0400
You may want to have a peak at the /tmp directory and make sure someone is not
dumping large files into the /tmp directory and impacting memory.
Applications (and sometimes Oracle) will place files under /tmp that can have a
very negative impact on overall memory performance on a Solaris server.
Just a thought...
Bill
-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of przemolicc@xxxxxxxxx
Sent: Monday, August 13, 2012 10:27 AM
To: oracle-l@xxxxxxxxxxxxx
Subject: Oracle & pagefaults (solaris)
Hi all,
we have been facing performance problems on our Solaris 10 Sparc based server
with several Oracle databases running on it.
It started 2 months ago and gradually is increasing. There is always high level
of syscalls when we face these problems:
09:20:03 25 8 0 68
09:30:02 22 7 0 70
09:40:03 23 8 0 70
09:50:03 23 7 0 69
10:00:03 22 9 0 69
10:10:03 25 34 0 41
10:20:03 28 28 0 44
10:30:03 27 24 0 49
10:40:02 24 8 0 68
10:50:03 27 19 0 54
11:00:02 31 27 0 41
11:10:21 29 48 0 23
11:20:03 36 56 0 9
11:30:05 32 51 0 18
11:40:03 37 43 0 20
11:50:06 28 59 0 14
12:00:06 32 61 0 7
12:10:03 38 26 0 36
12:20:02 34 9 0 57
12:30:02 35 8 0 58
12:40:03 35 9 0 56
Normal level of syscalls is about 7-10%. But when something is happening it
increases to over 50%.
Using DTrace I can find that kernel is working in 'pagefault' function:
......
unix`page_freelist_coalesce+0x894 [***]
0x1fe0000
unix`page_get_mnode_freelist+0x398
unix`page_get_freelist+0x428
unix`page_alloc_pages+0x110
genunix`anon_map_getpages+0x348
genunix`segvn_fault_anonpages+0x32c
genunix`segvn_fault+0x530
genunix`as_fault+0x4c8
unix`pagefault+0x68
unix`trap+0xd50
unix`utl0+0x4c
29062
unix`cpu_halt+0x10c
unix`cpu_halt+0x104
unix`idle+0x128
unix`thread_start+0x4
719133
(this is just part of the image - there are much more pagefaults then listed
above).
So natural is to check on behalf of which application kernel is working in
pagefaults:
[ High syscalls ]
CPU ID FUNCTION:NAME
96 85656 :tick-5sec
nscd 1
top 1
dtrace 5
perl 122
emagent 124
tnslsnr 1569
oracle 5538
[ Low (normal) syscalls ]
CPU ID FUNCTION:NAME
20 85656 :tick-5sec
nscd 1
dtrace 5
emagent 41
sh 91
perl 93
emdctl 243
tnslsnr 320
oracle 2466
When I watch which Oracle's PID are generating these high syscalls using 'ps'
most of them don't exists (!). Are they short lived processes ?
Our DBA claims that this is not a problem of Oracle but DTrace shows that
system is working on behalf of Oracle. Can you shed some light where our DBAs
should
look for any solution ? When I analyzed number of connections in listener log
they don't
differ much between low and high system calls.
Can you help me please ? I don't feel comfortable because my feeling is that I
am doing
DBAs homework but they claim that AWR report is the same as before so there is
nothing
they could do.
Best regards
Przemek
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