Re: timeout implementation issues

Jessica Perry Hekman wrote:
> On Mon, 1 Apr 2002, Tom Lane wrote:
>
> > On the other hand, we do not have anything in the backend now that
> > applies to just one statement and then automatically resets afterwards;
> > and I'm not eager to add a parameter with that behavior just for JDBC's
> > convenience. It seems like it'd be a big wart.
>
> Does that leave us with implementing query timeouts in JDBC (timer in the
> driver; then the driver sends a cancel request to the backend)?

No, I think we have to find a way to do this in the backend; just not
sure how yet.

I see the problem Tom is pointing out, that SET is ignored if the
transaction has already aborted:

test=> begin;
BEGIN
test=> lkjasdf;
ERROR: parser: parse error at or near "lkjasdf"
test=> set server_min_messages = 'log';
WARNING: current transaction is aborted, queries ignored until end of
transaction block
*ABORT STATE*
test=>

so if the transaction aborted, the reset of the statement_timeout would
not happen. The only way the application could code this would be with
this:

BEGIN WORK;
query;
SET statement_timeout = 4;
query;
SET statement_timeout = 0;
query;
COMMIT;
SET statement_timeout = 0;

Basically, it does the reset twice, once assuming the transaction
doesn't abort, and another assuming it does abort. Is this something
that the JDBC and ODBC drivers can do automatically?

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