DB server has a rest cyclically

From: Ko mi jung <gorgeous_at_ccs.sogang.ac.kr>
Date: Fri, 5 Dec 2003 16:34:01 +0900
Message-ID: <bqpb7l$q1$1@ccsun2.sogang.ac.kr>

We have problem that DB server has a rest cyclically when connected by many concurrent users.
We need help of someone who has a similar experience. Please see below.

Configuration of WEB server : SUN Fire 6800, CPU : 12, Memory : 24GB, OS : SUN OS 5.8 Web Server : Apache 1.3.26, Application Program : CGI, HTML
Configuration of DB server : SUN Fire 6800 CPU : 4 Memory : 8GB OS : SUN OS 5.8 DBS : ORACLE 9.2.0.4
Environment of DB server : ORACLE 9.2.0.4 Server = DEDICATED Process = 1024 session = 1131

System construction is that if users request services in Web browser, users receive answer
that comes from WEB server through DB server.( We don't use Web Application Server )
We have Web server and DB server inner same firewall

When 1000users send requests from WEB server to DB server at same times, DB server has a rest
at regular intervals ( ex. 10 ~ 20 seconds ) after DB server processes in some requests ( ex. 200requests )
and then processes and has a rest ..... repeatedly.

We monitored system when DB server has a rest. The result is that used part of CPU is less then 10%,
and there is no request processing.
And at this time we saw 'established service = 200' at DB server command < lsnrctl services >.
The result is that 200 requests is established and the rest requests don't still pass Listener.
Alert log and Listener log of DB server have no error

We are very curious about the reason that DB server doesn't service continuously.
We don't konw the problem is DB server , Network, or Firewall at all. We are waiting for reply anxiously.
( E-mail : albert07_at_sogang.ac.kr albert_at_ccs.sogang.ac.kr gorgeous_at_ccs.sogang.ac.kr )
Thanks for reading.

[ P.S. The result of test ]

test sql

sqlplus sguser/xxx_at_ORA9<<EOF
SELECT COUNT(*) FROM sguser.temp_test_log where cheorija = 'test1'; INSERT INTO temp_test_log (nyeondo, hakgi, test_num, cheori_ilja, cheorija)

                SELECT '2003','2',COUNT(*),SYSDATE,'test1' FROM HAKB_SUGANG;

COMMIT;
EOF

case 1 : We run 500 test sqls at the same time ( WEB server --> DB server : remote )

Result) process and then rest repeatedly. Process well 350, the rest died (time out)
case 2 : We run 500 test sqls ( DB server --> DB server : local )

Result) process all
case 3 : We run 500 test sqls in order ( WEB server --> DB server : remote )

Result) process all Received on Fri Dec 05 2003 - 01:34:01 CST