Re: Prepared statements, parameters and logging

[Oliver Jowett <oliver(at)opencloud(dot)com>]

Csaba Nagy wrote:

> Before I was using prepareThreshold='1', and I was seeing only such
> entries in the server log:
>
> duration: 5437.499 ms  statement: EXECUTE <unnamed>  [PREPARE:  SELECT
> ... ]
>
> Note the <unnamed> in the log entry, it was always there for each
> statement.

I believe that's logging execution of an unnamed portal, not an unnamed 
statement. I'm not sure whether the current server logging actually lets 
you tell whether a named statement was used/reused or not (at least that 
was one of my complaints about early versions of it -- haven't checked 
what current versions do).

If the statement name is logged, it'd be something like "S_12345".

> After setting prepareThreshold='0', I started getting 2 kinds of log
> entries, the ones like above, and the likes:
>
> duration: 2200.570 ms  statement: EXECUTE C_220047  [PREPARE:  SELECT
> ... ]
>
> Note the C_220047, that's what's changed...

C_.... are portals ("cursors")

If you're using setFetchSize() to avoid pulling in the whole resultset 
at once, the driver has to use a named statement and named portal 
regardless of the prepare-threshold setting (because portals are closed 
when their creating statement is closed, and the unnamed statement gets 
closed when reused)

-O