RE: Database sloowww...trying to figure out why...
- From: Chris Stephens <ChrisStephens@xxxxxxxxxx>
- To: "'oracle-l@xxxxxxxxxxxxx'" <oracle-l@xxxxxxxxxxxxx>
- Date: Tue, 30 Mar 2004 15:49:55 -0600
I thought that was a possibility too.
The buffer cache is over a gig...the entire database is around 50 gig.
...I haven't seen any swapping on the machine.
-----Original Message-----
From: Goulet, Dick [mailto:DGoulet@xxxxxxxx]
Sent: Tuesday, March 30, 2004 3:40 PM
To: oracle-l@xxxxxxxxxxxxx
Subject: RE: Database sloowww...trying to figure out why...
Shot from the hip here, but it would sound like your vendor has the buffer
cache up way too high in the first place. Sure the swapper isn't having a
field day?
Dick Goulet
Senior Oracle DBA
Oracle Certified 8i DBA
-----Original Message-----
From: Chris Stephens [mailto:ChrisStephens@xxxxxxxxxx]
Sent: Tuesday, March 30, 2004 4:24 PM
To: oracle-l@xxxxxxxxxxxxx
Subject: Database sloowww...trying to figure out why...
Well, what can I say...more performance problems in our apps environment.
The outsourcing company is suggesting things like increasing buffer cache
(seriously!).
This time I've successfully campaigned to alteast get perfstat installed on
the prod db. Here is what I've found so far.
After taking several snapshots it appears we have a cpu issue (sort
of...it's weird because the slowaris box doesn't look stressed for cpa AT
ALL!). As much as 80% of the response time is due to cpu usage. ...of that
cpu usage the majority of it is 'other cpu'. Absolutely everything I try
to do in there is slow (mostly look ups on the data dictionary to try and
figure out what's wrong). Without the ability to trace user sessions, I
thought I would trace my own. Executing statspack.snap takes as much as 25
seconds!!! So I enable 10046 trace and formatted the trace file through
tkprof. The database is 9203. The biggest waits in the trace file are due
to the execute phase. Here is an example:
INSERT into stats$sql_summary
( snap_id
, dbid
, instance_number
, text_subset
, sharable_mem
, sorts
, module
, loaded_versions
, fetches
, executions
, loads
, invalidations
, parse_calls
, disk_reads
, buffer_gets
, rows_processed
, command_type
, address
, hash_value
, version_count
, cpu_time
, elapsed_time
, outline_sid
, outline_category
, child_latch
)
select :b9
, :b8
, :b7
, substrb(sql_text,1,31)
, sharable_mem
, sorts
, module
, loaded_versions
, fetches
, executions
, loads
, invalidations
, parse_calls
, disk_reads
, buffer_gets
, rows_processed
, command_type
, address
, hash_value
, version_count
, cpu_time
, elapsed_time
, outline_sid
, outline_category
, child_latch
from stats$v$sqlxs
where is_obsolete = 'N'
and ( buffer_gets > :b6
or disk_reads > :b5
or parse_calls > :b4
or executions > :b3
or sharable_mem > :b2
or version_count > :b1
)
call count cpu elapsed disk query current
rows
------- ------ -------- ---------- ---------- ---------- ----------
----------
Parse 1 0.07 0.07 0 0 0
0
Execute 1 5.27 5.27 0 398 2738
6041
Fetch 0 0.00 0.00 0 0 0
0
------- ------ -------- ---------- ---------- ---------- ----------
----------
total 2 5.34 5.35 0 398 2738
6041
Misses in library cache during parse: 1
Optimizer goal: CHOOSE
Parsing user id: 266 (recursive depth: 1)
Rows Row Source Operation
------- ---------------------------------------------------
6041 VIEW (cr=0 r=0 w=0 time=4815086 us)
6041 FILTER (cr=0 r=0 w=0 time=4805641 us)
30284 SORT GROUP BY (cr=0 r=0 w=0 time=4760583 us)
33809 FIXED TABLE FULL X$KGLCURSOR (cr=0 r=0 w=0 time=3106069 us)
Elapsed times include waiting on following events:
Event waited on Times Max. Wait Total
Waited
---------------------------------------- Waited ----------
------------
control file sequential read 24 0.00 0.00
db file sequential read 4 0.00 0.00
async disk IO 2 0.00 0.01
db file single write 2 0.00
0.00
control file parallel write 4 0.00 0.00
rdbms ipc reply 2 0.00 0.00
I'm not so good at looking at raw trace files so I'm not sure what part of
that is relevant and what's not.
I guess what I'm asking is that now that I know that much of our database
time is spent on cpu and it appears (at least in my case) that much of that
is the execute phase where should I go from hear? ...I would imagine
there's a plethora of info in the raw trace file that I'm not privi to due
to ignorance. ...in my defense, I did try getting the miracle 10046
doohickey to work but have given up because I'm on hp not red hat and I
can't figure out what the equivalent of 'ls -l --time=atime *' is in ksh.
...and then it's not guaranteed to work because of possible differences in
trace file format between red hat and hp.
If anyone would like to see the full trace file, I have attached that.
Thanks for any help.
Anyone know of a 10046 parser that works in an hp environment?
Chris
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