Re: GUC_REPORT for protocol tunables was: Re: Optimize binary serialization format of arrays with fixed size elements

On Mon, Jan 23, 2012 at 9:59 AM, Marko Kreen <markokr(at)gmail(dot)com> wrote:
> On Sun, Jan 22, 2012 at 11:47 PM, Mikko Tiihonen
> <mikko(dot)tiihonen(at)nitorcreations(dot)com> wrote:
>> * introduced a new GUC variable array_output copying the current
>>  bytea_output type, with values "full" (old value) and
>>  "smallfixed" (new default)
>> * added documentation for the new GUC variable
>
> If this variable changes protocol-level layout
> and is user-settable, shouldn't it be GUC_REPORT?
>
> Now that I think about it, same applies to bytea_output?
>
> You could say the problem does not appear if the
> clients always accepts server default.  But how can
> the client know the default?  If the client is required
> to do "SHOW" before it can talk to server then that
> seems to hint those vars should be GUC_REPORT.
>
> Same story when clients are always expected to set
> the vars to their preferred values.  Then you get
> clients with different settings on one server.
> This breaks transaction-pooling setups (pgbouncer).
> Again, such protocol-changing tunables should be
> GUC_REPORT.

Probably so. But I think we need not introduce quite so many new
threads on this patch. This is, I think, at least thread #4, and
that's making the discussion hard to follow.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company