Database slow on startup

Question

Hi,
I am a new administrator and am facing an issue with my Oracle 8.1.6 database.I have encountered a problem where somedays my Oracle becomes extemely slow after startup.Almost it goes into a hung kind of state wheneever any reports etc are accessed from the application.After waiting for abt half an hour or so everything goes back to normal.
Has anyone faced a similar kind of problem .Has it got something to do with the recovery process taking place during startup.Can you please help me find a solution to this.
Regards,
Dinesh

Answer 1

in order to be sure you may watch the operating system cpu, disk, memory and network load and catch the top consuming proceses - you can use sar iostat vmstat and netstat for unix -
After match them from v$ views to find out the sql query, what they are waiting etc. - you can use this query to identify what is going on behind -
-- who is doing what
SELECT sq.sql_text,
se.status,
se.username,
se.osuser,
se.terminal,
se.machine,
'ALTER SYSTEM KILL SESSION ''' || se.sid || ', ' || se.serial# ||
''' IMMEDIATE ;',
se.sid,
se.serial#,
pr.spid,
se.saddr,
se.schemaname,
se.program,
se.logon_time,
sq.hash_value,
sq.address,
sq.buffer_gets,
sq.disk_reads,
sq.executions,
sq.fetches,
sq.rows_processed,
io.block_gets,
io.consistent_gets,
io.physical_reads,
io.block_changes,
io.consistent_changes,
se.module,
se.action,
se.client_info,
sw.event,
sw.p1text,
sw.p1,
sw.p2text,
sw.p2,
pr.pga_used_mem,
pr.pga_alloc_mem,
pr.pga_freeable_mem,
pr.pga_max_mem,
'exec dbms_support.start_trace_in_session(' || se.sid || ', ' || se.serial# || ', ' ||
'waits => TRUE' || ', ' || 'binds => TRUE);',
'exec dbms_support.stop_trace_in_session(' || se.sid || ', ' || se.serial# || ');'
FROM v$session se, v$sqlarea sq, v$process pr, v$session_wait sw, v$sess_io io
WHERE status IN ('ACTIVE', 'KILLED', ' INACTIVE', ' CACHED', ' SNIPED')
AND se.sql_hash_value = sq.hash_value(+)
AND se.sql_address = sq.address(+)
AND se.paddr = pr.addr
AND se.sid = sw.sid
AND se.sid = io.sid
ORDER BY sq.sql_text, se.username, se.schemaname, se.osuser, se.program, se.sid
You need to match the top consumer os processes' id with the "pr.spid" column, then you might look at the other columns of that row for details.
Also the database runs a number of jobs - backups, etc. these may be the problems.