Slow to connect to oracle w/ JDBC & SQLPLUS over network

Posted on 2002-04-03
Last Modified: 2008-02-07
We're having a problem where it takes up to 12 seconds to establish a new connection over network to a Oracle Database (running on a 16 processor HP box). The Client runs on Win2k. Both JDBC and SQLPLUS takes 8-12 seconds to connect to Oracle, but after the connection is established, the queries are lightning fast (so the problem is solely in the connect area).

I assume it can be the TNS listner. Running tcp sniffers we can see the connection is trying to be established. The client sends a TCP message "ACK TOO LONG" then Oracle responds with keep alive. Nothing happens for about 6-10 seconds before Oracle asks to retransmit and at that time a new connect is sent.

Does anyone know what can be wrong? Could it help to setup a seperate TNSListner for this? Is there an ultimate setup? Could it be something else than the TNS listner?

Any help would be appriciated greatly!

- Morten
Question by:mortenmo

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are you using the oracle MTS - the shared server mode for the DB connections, if that is the case then inital connection takes a bit longer than the dedicated server mode (which is oracle default)

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As arun04 suggested above, if you are using the MTS or even connection pooling, you will experience delays in connecting. The "ultimate" setup for you would be to have dedicated connections and do away with MTS. But obviously you would need more resources on the server to manage this. Alternatively you can create a separate entry in tnsnames file for dedicated connections and use them for "special" cases.



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Few things:

If you login the HP box, connect to database there using sql*plus (sqlplus usrname/passwd@tns_alias), does the connection show similar pattern of slowness?

Can you post the version of your
OS (HP-UX 11?) and Oracle (8.1.7?). Also
if the OS is 64bit and Oracle is 32bit?

Can you check if /etc/hosts has the
permission -rw-r--r--?

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Are you using names resolution using an Oracle names server or DNS etc? Use a plain IP address in your tnsnames.ora file and see if that helps.

Is the network you mentioned a LAN or a WAN

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k_murli_krishna earned 300 total points
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1) Decrease the number of existing connections i.e. the number of schemas or the clients configured to connect to existing schemas. This will decrease connection time a lot.

2) For connection pooling use oci8 and not thin drivers.

3) As the previous experts mentioned dedicated server mode which is default should be retained.

4) Make sure clients either oracle or middle end application servers disconnect as soon as work is over.

5) The CPU, primary and secondary memory of clients, servers and network load other than oracle also matter a lot.

6) If connections are made and closed within a method which are multi-threaded, make sure the methods are not synchronized.

7) If it is a MAN/WAN, the oracle server should be a proxy/firewall OR direct IP's should be configured which will be faster than a VPN secure connections based oracle connection.

8) Remove all extra objects, jobs etc. running on the server.

9) Try to see available protocols and viability and speed in your network.

10) Make sure number of client windows/connections are kept the minimum and restart services and database to check if open/inconsistent connections termination can improve connectivity.

--- k_murli_krishna

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Please close this question if you are through.

--- k_murli_krishna

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Finalized by Moondancer - EE Moderator

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