[pgpool-hackers: 1651] Re: kind does not match error in pgpool

[Muhammad Usama]

On Wed, Jun 22, 2016 at 7:47 AM, Tatsuo Ishii <ishii at postgresql.org> wrote:

> > On Tue, Jun 21, 2016 at 6:11 AM, Tatsuo Ishii <ishii at postgresql.org>
> wrote:
> >
> >> > Hi Ishii-San
> >> >
> >> > Can you please have a look at the attached patch, It try to solve this
> >> > "Kind does not match .." problem by ignoring the notice messages while
> >> > reading the backend response in read_kind_from_backend() function
> >>
> >> Doesn't this patch simply ignore important messages like this?
> >>
> >
> > Basically patch only ignores the notice log messages and these messages
> are
> > important, especially ones with severity level of WARNING and NOTICE, to
> > inform the user about some critical issue.
> > I may be wrong, but I don't think these log message are important in
> terms
> > of PG protocol flow. i.e. notice (kind = 'N') message only contains the
> log
> >  and is delivered to frontend (pgpool-II in our case) depending on
> > *client_min_messages* settings in postgresql.conf.
> > So I think it should be safe to ignore these.
>
> Is it possible to send the NOTICE message (kind = N) to frontend,
> rather than discard it? By the time when read_kind_from_backend() gets
> called, all the messages are sent to frontend and it should be in the
> message boundary (i.e. not in the middle of the message packet), I
> guess it should be safe.
>

This is a good idea, But since notice messages (packet kind = N) can
contain a log for severity level ranging from DEBUG to WARNING
so instead of forwarding all notice type messages to frontend we should
only froward the messages with severity >= WARNING or may be consider
pgpool's *client_min_messages* config parameters and if the message
received from backend has severity >= client_min_messages only then forward
it to the frontend



> Best regards,
> --
> Tatsuo Ishii
> SRA OSS, Inc. Japan
> English: http://www.sraoss.co.jp/index_en.php
> Japanese:http://www.sraoss.co.jp
>
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