Filtering & Request Level Logging

[justin_willey]

Request level logging can be very useful in seeing what is actually happening in a live database, but the higher levels of logging (eg SQL, PLAN etc) do involve a fair degree of server load - especially with many hundred simultaneous users. Ideally one could just log a single connection but the way the docs read:

Output to the request log can be filtered to include only requests from a specific connection or from a specific database, using the sa_server_option system procedure.

everything (ie for all connections / databases) is being collected (with the consequent server load) but the output is being filtered down to a single user.

Am I reading too much into the word "filtered" or is that the correct interpretation?

[VolkerBarth]

If my understanding of the docs is correct, you should be able to collect only RLL data for a specified connection via

CALL sa_server_option( 'RequestFilterConn', connection-id );


To cite:

RequestFilterConn

Filter the request logging information so that only information for a particular connection is logged. This can help reduce the size of the request log file when monitoring a database server with many active connections or multiple databases. 

So in my humble opinion that would mean the data collecion is already filtered, not the later RLL output. - Note, that's just another WAG for today:)

[justin_willey]

It isn't absolutely clear is it? The word "logged" could be taken as meaning "only data for a particular connection is written to the log" rather than "only data for a particular connection is collected"

It talks about keeping down the log file size but doesn't mention the server load.

Mmmm.. I may be being paranoid but it doesn't mean they aren't out to get me!

[VolkerBarth]

Yes, after reading the "About Request logging" page I thought it could also be meant as you have expected... - "Suck it and see" is not your preferred choice here, correct?

[justin_willey]

Not with 700 users all beavering away- no 🙂 It's hard to tell on a quiet system and too late to find out on a busy one when it crashes!

[Breck_Carter]

This is an Occam's Razor moment, methinks, as in "take the simple interpretation of 'only information for a particular connection is logged'".