Re: [PATCHES] libpq type system 0.9a - Mailing list pgsql-hackers

From Andrew Dunstan
Subject Re: [PATCHES] libpq type system 0.9a
Date
Msg-id 47FCB5B7.7050202@dunslane.net
Whole thread Raw
In response to Re: [PATCHES] libpq type system 0.9a  (Andrew Chernow <ac@esilo.com>)
List pgsql-hackers

Andrew Chernow wrote:
> Andrew Dunstan wrote:
>>
>>
>> Merlin Moncure wrote:
>>> However, due to libpq limitations, if any datatype must
>>> return text the entire result must be text (resultFormat)...this is 
>>
>> I'm surprised you didn't try to address that limitation.
>>
>>
>
> That would change the existing behavior of resultFormat, although not 
> terribly.  Currently, the server will spit back an error if you use 
> binary results but some type hasn't implemented a send/recv.  Instead 
> of an error, the server could "fallback" to the type's in/out routines 
> and mark the column as text format.
>
> I think the "fallback" approach is more intelligent behavior but such 
> a change could break libpq clients.  They might be blindly ASSuming if 
> the exec worked with resultFormat=1, that everything returned by 
> PQgetvalue will be binary (I'm guilty of this one, prior to libpqtypes).
>
> Our patch would work with no changes because it supports text and 
> binary results.  So, each type handler already toggles itself based on 
> PQfformat.

That makes it sound more like a protocol limitation, rather than a libpq 
limitation. Or am I misunderstanding?

cheers

andrew


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