Re: Small question - Mailing list pgsql-general

From Jan Wieck
Subject Re: Small question
Date
Msg-id 200203221911.g2MJBHl16196@saturn.janwieck.net
Whole thread Raw
In response to Re: Small question  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Small question
List pgsql-general
Tom Lane wrote:
> Jan Wieck <janwieck@yahoo.com> writes:
> > Joep deVocht wrote:
> >> Is there a way to determine whether a transaction
> >> is started and not ended yet?
>
> >     I think it's time to add  a  little  boolean  function,  that
> >     actually  returns IsTransactionBlock(), and have a libpq side
> >     wrapper around PQfn() calling it.
>
> If you're in TRANSACTION ABORT state, I do not think that will work.

    Sort  of,  because  that's  the  only moment when PQfn() will
    result in something different than PGRES_COMMAND_OK :-)


>
> Offhand this seems more of a protocol issue.  A straightforward solution
> would be to add a status indicator (with three states: out of
> transaction, in transaction, in aborted transaction) to the
> ReadyForQuery message, but we can't do that without a protocol change,
> which is probably more trouble than it's worth.
>
> It seems like it might be possible for libpq (or other clients) to keep
> track of the transaction state by paying attention to BEGIN, COMMIT,
> ABORT command-completion tags and ERROR messages, but I haven't worked
> through the details.

        PQexec(c, "BEGIN; SELECT now()");

    Will there even be a BEGIN command tag sent?


Jan

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