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Did performance problems happen overnight, or did they sneak up on you? Any clue what caused the performance problems (e.g. loading 20K users into .LRN)
Is the file system out of space? Is the machine swapping to disk constantly?
Isolating and solving database problems.
Without daily internal maintenance, most databases slowly degrade in performance. For PostGreSQL, see the section called “Vacuum Postgres nightly”. For Oracle, "gather schema stats" (more info?).
You can track the exact amount of time each database query on a page takes:
Go to Main Site : Site-Wide Administration : Install Software
Click on "Install New Application" in "Install from OpenACS Repository"
Choose "ACS Developer Support">
After install is complete, restart the server.
Browse to Developer Support, which is automatically mounted at /ds.
Turn on Database statistics
Browse directly to a slow page and click "Request Information" at the bottom of the page.
This should return a list of database queries on the page, including the exact query (so it can be cut-paste into psql or oracle) and the time each query took.
Identify a runaway Oracle query: first, use ps aux or top to get the UNIX process ID of a runaway Oracle process.
Log in to SQL*Plus as the admin:
[service0 ~]$ svrmgrl
Oracle Server Manager Release 3.1.7.0.0 - Production
Copyright (c) 1997, 1999, Oracle Corporation. All Rights Reserved.
Oracle8i Enterprise Edition Release 8.1.7.3.0 - Production
With the Partitioning option
JServer Release 8.1.7.3.0 - Production
SVRMGR> connect internal
Password:See all of the running queries, and match the UNIX PID:
select p.spid -- The UNIX PID
,s.sid ,s.serial#
,p.username as os_user
,s.username ,s.status
,p.terminal ,p.program
from v$session s ,v$process p
where p.addr = s.paddr
order by s.username ,p.spid ,s.sid ,s.serial# ;See the SQL behind the oracle processes:
select s.username
,s.sid ,s.serial#
,sql.sql_text
from v$session s, v$sqltext sql
where sql.address = s.sql_address
and sql.hash_value = s.sql_hash_value
--and upper(s.username) like 'USERNAME%'
order by s.username ,s.sid ,s.serial# ,sql.piece ;To kill a troubled process:
alter system kill session 'SID,SERIAL#'; --substitute values for SID and SERIAL#