I used tcpdum tool on windows run the command tcpdump host databaseserver On Fri, Jun 20, 2008 at 5:29 PM, Desai, Bhavik (MLITS) <Bhavik_Desai@xxxxxx> wrote: > *Hi,* > > * * > > *Can I request you to show how did you take tcpdump for a query ?* > > * * > > -----Original Message----- > *From:* oracle-l-bounce@xxxxxxxxxxxxx [mailto: > oracle-l-bounce@xxxxxxxxxxxxx] *On Behalf Of *qihua wu > *Sent:* Friday, June 20, 2008 2:44 PM > *To:* oracle-l > *Subject:* 3 round trips over network for simply "select sysdate from > dual" > > > > Hi, all > > When using tcpdump to check what happen over the network when do a simple > query as > SQL> select sysdate from dual; > > SYSDATE > --------- > 20-JUN-08 > > The tcpdump is as following, 3 round trips between the server and client. > Why so many trips? Don't we only need to 1 round trip as client send the > query and the server reply? > > 16:56:13.354672 IP host1 > host2.1580: . 7898:8 054(156) ack 6755 win 32768 > 16:56:13.354683 IP host2.1580 > host1: . 6755:6 836(81) ack 8054 win 32768 > 16:56:13.521731 IP host1 > host2.1580: . 8054:8 126(72) ack 6836 win 32768 > 16:56:13.521744 IP host2.1580 > host1: . 6836:6 853(17) ack 8126 win 32768 > 16:56:13.688967 IP host1 > host2.1580: . 8126:8 141(15) ack 6853 win 32768 > 16:56:13.688980 IP host2.1580 > host1: . 6853:6 874(21) ack 8141 win 32768 > > > And the expert says below: one additional roundtrip to initiate the query. > Don't quite understand why we need additional roundtrip to initiate. > http://www.adp-gmbh.ch/ora/sqlplus/arraysize.html > > Thanks, > Qihua > ------------------------------ > This message w/attachments (message) may be privileged, confidential or > proprietary, and if you are not an intended recipient, please notify the > sender, do not use or share it and delete it. Unless specifically indicated, > this message is not an offer to sell or a solicitation of any investment > products or other financial product or service, an official confirmation of > any transaction, or an official statement of Merrill Lynch. Subject to > applicable law, Merrill Lynch may monitor, review and retain > e-communications (EC) traveling through its networks/systems. The laws of > the country of each sender/recipient may impact the handling of EC, and EC > may be archived, supervised and produced in countries other than the country > in which you are located. This message cannot be guaranteed to be secure or > error-free. This message is subject to terms available at the following > link: http://www.ml.com/e-communications_terms/. By messaging with Merrill > Lynch you consent to the foregoing. > ------------------------------ > >