Re: php with postgres

Marcus B?rger wrote:
> >> BM> I don't see why you wouldn't just do BEGIN;COMMIT;RESET ALL; when you
> >> BM> pass the connection to a new client.
> >>
> >>
> >> Bruce you said RESET ALL is available since 7.2. I am currently checking for
> >> the lib version but it would be more correct to check something on the server.
> >> So the question what do i check?
>
> BM> We usually use SELECT version().
>
>
> ATM i have a patch doing the following:
> Connect:
> If PQprotocolVersion() is available and >= 3 PQparameterStatus() is available
> then i check the server version. Else i check the lib version (*).
> If the version to check is >= 7.2 ido one of the following:
> - If one of PQprotocolVersion() and PQtransactionStatus() is unavailable or
> protocol version < 3:
> "BEGIN;COMMIT;RESET ALL;"

I believe this should be BEGIN;ROLLBACK;RESET ALL; because our default
for a client that disconnects is to abort the transaction.

> - If protocol version >= 3 and transaction status == PQTRANS_IDLE:
> "RESET ALL;"
> - If protocol version >= 3 and transaction status != PQTRANS_IDLE:
> "COMMIT;RESET ALL;"

Should be "ROLLBACK;RESET ALL;".

Nice version test code, sounds good.

>
> Disconnect:
> - When PQprotocolVersion() And PQtransactionStatus() are available then
> i check whether status is PQTRANS_IDLE. If so i do:
> "ROLLBACK;"
> - If the functions are not available in the client libs i do:
> "BEGIN;ROLLBACK;"
>
> Does this sound the correct behavior?

I am confused why you are doing stuff on connect and disconnect. Seems
it should all be done on disconnect so you don't leave open transactions
in the pooled connections --- it will keep locks around too long and
reduce the usefulness of vacuum. If we clean up everything on
disconnect, aren't we sure that the connection status will be fine?

> And would "select split_part(version(), ' ', 2);" be too much of a slowdown to
> do the version detection in the startup sequence completely correct?

Seems fine. Since you are doing pooled connections, you shouldn't be
doing this too often anyway.

--
Bruce Momjian | http://candle.pha.pa.us
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