patch: assign result of query to psql variable - Mailing list pgsql-hackers

---------- Forwarded message ----------
From: Pavel Stehule <pavel.stehule@gmail.com>
Date: 2012/10/12
Subject: Re: [HACKERS] proposal - assign result of query to psql variable
To: Shigeru HANADA <shigeru.hanada@gmail.com>
Kopie: David Fetter <david@fetter.org>, Tom Lane <tgl@sss.pgh.pa.us>,
PostgreSQL Hackers <pgsql-hackers@postgresql.org>


Hello

here is updated version of gset patch.

* merge Shigeru's doc patch
* rename psql regression test from "psql" to "psql_cmd"

Regards

Pavel Stehule


2012/9/27 Pavel Stehule <pavel.stehule@gmail.com>:
> Hello
>
> 2012/9/21 Shigeru HANADA <shigeru.hanada@gmail.com>:
>> Hi Pavel,
>>
>> (2012/09/21 2:01), Pavel Stehule wrote:
>>>> - Is it intentional that \gset can set special variables such as
>>>> AUTOCOMMIT and HOST?  I don't see any downside for this behavior,
>>>> because \set also can do that, but it is not documented nor tested at all.
>>>>
>>>
>>> I use a same "SetVariable" function, so a behave should be same
>>
>> It seems reasonable.
>>
>>>> Document
>>>> ========
>>>> - Adding some description of \gset command, especially about limitation
>>>> of variable list, seems necessary.
>>>> - In addition to the meta-command section, "Advanced features" section
>>>> mentions how to set psql's variables, so we would need some mention
>>>> there too.
>>>> - The term "target list" might not be familiar to users, since it
>>>> appears in only sections mentioning PG internal relatively.  I think
>>>> that the feature described in the section "Retrieving Query Results" in
>>>> ECPG document is similar to this feature.
>>>> http://www.postgresql.org/docs/devel/static/ecpg-variables.html
>>>
>>> I invite any proposals about enhancing documentation. Personally I am
>>> a PostgreSQL developer, so I don't known any different term other than
>>> "target list" - but any user friendly description is welcome.
>>
>> How about to say "stores the query's result output into variable"?
>> Please see attached file for my proposal.  I also mentioned about 1-row
>> limit and omit of variable.
>
> should be
>
>>
>>>> Coding
>>>> ======
>>>> The code follows our coding conventions.  Here are comments for coding.
>>>>
>>>> - Some typo found in comments, please see attached patch.
>>>> - There is a code path which doesn't print error message even if libpq
>>>> reported error (PGRES_BAD_RESPONSE, PGRES_NONFATAL_ERROR,
>>>> PGRES_FATAL_ERROR) in StoreQueryResult.  Is this intentional?  FYI, ecpg
>>>> prints "bad response" message for those errors.
>>>
>>> yes - it is question. I use same pattern like PrintQueryResult, but
>>> "bad response" message should be used.
>>>
>>> I am sending updated patch
>>
>> It seems ok.
>>
>> BTW, as far as I see, no psql backslash command including \setenv (it
>> was added in 9.2) has regression test in core (I mean src/test/regress).
>>  Is there any convention about this issue?  If psql backslash commands
>> (or any psql feature else) don't need regression test, we can remove
>> psql.(sql|out).
>> # Of course we need to test new feature by hand.
>
> It is question for Tom or David - only server side functionalities has
> regress tests. But result of some backslash command is verified in
> other regress tests. I would to see some regression tests for this
> functionality.
>
>>
>> Anyway, IMO the name psql impresses larger area than the patch
>> implements.  How about to rename psql to psql_cmd or backslash_cmd than
>> psql as regression test name?
>>
>
> I have no idea - psql_cmd is good name
>
> Regards
>
> Pavel
>
>> --
>> Shigeru HANADA