Re: timeout implementation issues - Mailing list pgsql-hackers

From Hiroshi Inoue
Subject Re: timeout implementation issues
Date
Msg-id 3CB24AB2.D2BDD33B@tpf.co.jp
Whole thread Raw
In response to Re: timeout implementation issues  (Bruce Momjian <pgman@candle.pha.pa.us>)
Responses Re: timeout implementation issues  (Bruce Momjian <pgman@candle.pha.pa.us>)
List pgsql-hackers
Bruce Momjian wrote:
> 
> Hiroshi Inoue wrote:
> > Bruce Momjian wrote:
> > >
> > > Hiroshi Inoue wrote:
> > > > Bruce Momjian wrote:
> >
> > > > > > > They want the timeout for only the one statement, so they have to set it
> > > > > > > to non-zero before the statement, and to zero after the statement.
> > > > > >
> > > > > > Does setQueryTimeout() issue a corresponding SET QUERY_TIMEOUT
> > > > > > command immediately in the scenario ?
> > > > >
> > > > > Yes.  If we don't make the SET rollback-able, we have to do all sorts of
> > > > > tricks in jdbc so aborted transactions get the proper SET value.
> > > >
> > > > In my scenario, setQueryTimeout() only saves the timeout
> > > > value and issues the corrsponding SET QUERY_TIMEOUT command
> > > > immediately before each query if necessary.
> > >
> > > Yes, we can do that,
> >
> > Something like my scenario is needed because there could be
> > more than 1 statement objects with relatively different
> > query timeout at the same time in theory.
> 
> Yes, if you want multiple timeouts, you clearly could go in that
> direction.  Right now, we are considering only single-statement timing
> and no one has asked for multiple timers.

I don't ask multiple timers. ODBC driver would be able
to handle multiple timeouts without multiple timers in
my scenario.

> > > but it requires an interface like odbc or jdbc.  It
> > > is hard to use for libpq or psql.
> >
> > We shouldn't expect too much on psql in the first place
> > because it isn't procedural. I don't expect too much on
> > libpq either because it's a low level interface. However
> > applications which use libpq could do like odbc or jdbc
> > does. Or libpq could also provide a function which encap-
> > sulates the query timeout handling if necessary.
> 
> I certainly would like _something_ that works in psql/libpq,

Please don't make things complicated by sticking to such
low level interfaces.

regards,
Hiroshi Inoue


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