Re: XMLSERVICE with .Net

From: Alan Seiden
since XMLCGI communicates via a web server and CGI  jobs,
it probably won't be as fast as calling XMLSERVICE with stored 
procedures, such as through the ibm_db2 or odbc transports ...

Actually, I've done several comparisons between CGI vs. QZDASOINIT interfaces and performance is nearly identical with respect to socket communications, database retrieval, and generating formatted response streams. ODBC  is quite comparable to the HTTP protocol in terms of the size of request and response headers.

However, using ODBC to return a result set of say 6 fields per record only adds something like 13 to 24 bytes per record, while an XML response may add something like 100 to 150 bytes per record.

Getting a connection, querying an IBM i database, and generating a formatted output stream using both CGI and QZDASOINIT performs great. The point where you take a big performance hit is on the receiving end, where a client parses a formatted result stream and maps it to some client object.

For example, when connecting to a QZDASOINIT job and downloading a 2,450 record table from an IBM i database to a Visual Foxpro table, a formatted result set is returned over a LAN in less than 100 milliseconds. You can measure that with a tool like Wire Shark. But parsing it, and loading it into a local Foxpro table takes something like 8 seconds.

Where's the performance hit? It's on the client!

-Nathan.