Re: SQLNET overhead query

Fuzz wrote in message <373b6218.1022345_at_news.ibm.net.il>...

>Anyone knows what's the SQLNET overhead : if I pass through it say a
>5 k data, how many k's would be the output??

That also depends on the IP packet sizes that are created. There's somewhere a setting in SQL*Net that allows you to set a rowsize/packet size buffer. Microsoft's ODBC driver for Oracle for example allows you to set this settings. By default the packet size is something like 256 bytes (from some sniff traces I ran last year). You can bump up the size to about 1.4KB and really get a good and fast thruput.

The only way to get an accurate estimate of network size overheads on SQL statements, is to sniff the traffic from a client to a server. Microsoft ships network sniffers with NT Server (or is that Enterprise Server only?) and with their SMS product. You also get free sniffers for Linux - some of them real hacker tools for getting passwords and stuff too... ;-)

Also, if the client uses Microsoft database access libraries (ODBC, ADO, Jet Engine, or whatever other flavours they have), be exceptionally careful. Certain of these "methods" can cause -huge- overheads in the traffic that is generated as a lot of SQLs are created and executed by the driver software itself to get a "feel" for the database. The wrong db access method in Visual Basic to Oracle... I've personally run sniffer traces where the VB traffic was up to 20x more than the native traffic (e.g. SQL*Plus or Delphi) ito of number of packets.

regards,
Billy Received on Fri May 14 1999 - 03:20:29 CDT