Re: SQL*Net more data from client description

On Jan 26, 12:10 pm, "Steve Howard" <stevedhow..._at_gmail.com> wrote:
> Does the description in the standard docs make any sense to anyone
> besides me?
>
> http://download-east.oracle.com/docs/cd/B19306_01/server.102/b14237/w...
>
> /*********************
> ***************************************************************/
>
> SQL*Net more data from client
>
> The server is performing another send to the client. The previous
> operation was also a send to the client.
>
> Wait Time: The time waited depends on the time it took to receive the
> data (including the waiting time).
>
> Parameters:
>
> driver id
>
> See "driver id" on page A-8.
>
> #bytes
>
> The number of bytes received from the client.
>
> /*********************
> ***************************************************************/
>
> SQL*Net more data to client
>
> The server process is sending more data/messages to the client. The
> previous operation to the client was also a send.
>
> Wait Time: The actual time it took for the send to complete.
>
> /*********************
> ***************************************************************/
>
> When does the server ever *receive* anything?
>
> Thanks,
>
> Steve

The description make sense to me.

If the amount of data that Oracle must transmit to the client exceeds the MTU (maximum transmission unit) size for a single packet, the data will be broken up into multiple packets. Depending on the setting that determines the number of such packets that may be transmitted before a confirmation packet is received from the client (that allows delayed ACKs), Oracle may be able to send one to twenty (or some arbitrary number) packets before pausing for the confirmation packet. Once the confirmation packet is received, Oracle may send the next group of packets. This wait event is likely close to meaningless on a LAN (unless there is a mismatch between client and server settings for delayed ACKs), but with high latencies that are common with WAN connections, this may be an important wait event, which might signify that the client is requesting large data sets and performing filtering of data locally, rather than allowing the database server to pre-filter the data sets.

Charles Hooper
PC Support Specialist
K&M Machine-Fabricating, Inc. Received on Fri Jan 26 2007 - 12:41:45 CST