TKProf Output: SQL*Net message from client

Question

I am currently in the process of debugging a database performance issue. I have run extended trace on the suffering oracle box to obtain a trace file which I have analyzed using tkprof.

One thing that caught my eye straight away was the following output;

  Elapsed times include waiting on following events:
  Event waited on                             Times   Max. Wait  Total Waited
  ----------------------------------------   Waited  ----------  ------------
  SQL*Net message to client                       4        0.00          0.00
  SQL*Net message from client                     4      109.06        141.31

I have run the relate query manually via a SQL client an it executes in a timely fashion. So I don't think its cause directly by the query.

Can some one clarify what exactly "SQL*Net message from client" means ?

Does anyone have any idea what could be causing such large wait times ?

Thanks in advance

Karl

Solution 1

SQL*Net message from client means the time taken by oracle waiting for input from the client that you are connecting with. It's often thought to be an "idle" event, so nothing to worry about; however, this link disagrees. You might find that your client is the one taking the time so you could optimise your application not the queries it uses.

http://oracletoday.blogspot.com/2005/09/sqlnet-message-from-client.html

Also, another good link is http://www.dba-oracle.com/m_sql_net_message_to_client.htm

Solution 2

There is really good post talking about "Oracle: Network Waits"

Link:https://sites.google.com/site/embtdbo/wait-event-documentation/oracle-network-waits

Contents

1 Introduction
2 SQL*Net Wait Events
    2.1 SQL*Net message from client
    2.2 SQL*Net message to client 
    2.3 SQL*Net more data to client 
    2.4 SQL*Net more data from client
    2.5 SQL*Net break/reset to client
    2.6 DBLINK SQL*Net Waits
3 Analysis and Tuning
    3.1 SDU
    3.2 RECV_BUF_SIZE and SEND_BUF_SIZE