First webservice call with UTL_HTTP is slow

Question

Hi,
When i do several webservice calls with the utl_http methods, the first webservice call takes a lot of time (sometimes more than 10-20 seconds). Every other webservice call (after this one) goes very fast (not even a second).
Any ideas to make that first call faster?
Thx.

Answer 1

Davy wrote:
When i do several webservice calls with the utl_http methods, the first webservice call takes a lot of time (sometimes more than 10-20 seconds). Every other webservice call (after this one) goes very fast (not even a second).Don't see how this is an Oracle problem.
Oracle creates a tcp socket and makes a socket call using the http application protocol. If this is slow, then there is either a performance issue at networking level, or a performance issue at the remote server that accepts and services the tcp connection.
Network level - as Sybrand mentioned, it can be DNS related. You make the call using a hostname. That hostname needs to be resolved into an IP address. The network layer is slow (because of a problematic DNS server for example) to resolve that hostname into an IP address. Similar thing can be happening on the web server side. Reverse DNS lookup is used to determine what the hostname of the Oracle server is, using the IP address of the incoming connection.
The web server/service can be slow - the 1st request may make a lot of physical I/O calls. The kernel buffers the data. Subsequent I/O from this web service servicing new calls finds the data in the file cache via must faster logical I/O.
So you need to isolate and monitor these layers, the network and the web server, to determine what the reason is for the 1st call to be seemingly slow and subsequent calls not.