Re: proposal: schema PL session variables - Mailing list pgsql-hackers

From Pavel Stehule
Subject Re: proposal: schema PL session variables
Date
Msg-id CAFj8pRDxbiKXguX0uOHyaS9Jou_RxBDKOcO4CAU04OaMgWSyAg@mail.gmail.com
Whole thread Raw
In response to Re: proposal: schema PL session variables  (Marko Tiikkaja <marko@joh.to>)
Responses Re: proposal: schema PL session variables
List pgsql-hackers


2016-02-09 15:32 GMT+01:00 Marko Tiikkaja <marko@joh.to>:
On 08/02/16 14:16, Pavel Stehule wrote:
2016-02-08 13:53 GMT+01:00 Marko Tiikkaja <marko@joh.to>:

Yeah, and that's exactly what I don't want, because that means that CREATE
SCHEMA VARIABLE suddenly breaks existing code.


theoretically yes, but this conflict can be 100% detected - so no quiet bug
is possible, and plpgsql_check can find this issue well. If you don't use
schema variable, then your code will be correct. You have to explicitly
create the variable, and if there will be any problem, then the problem
will be only in PL functions in one schema. And you can identify it by
statical analyse.

I'm sorry, but I think you've got your priorities completely backwards.  You're saying that it's OK to add a footgun because blown-off pieces of feet can be found by using a third party static analyzer barely anyone uses.  And at best, that footgun is only a very minor convenience (though I'd argue that omitting it actually hurts readability).

I don't block the integration plpgsql_check to upstream. I spent hundreds hours for it.

Can we look on this problem with different side? What I can do it for safe using proposed schema variables.

The possible ways:

1. requirement prefix like : or @. I don't prefer it because a) hard to find a agreement - Oracle fans like ":", MSSQL like @, other maybe $, b) with any currently unsupported syntax I have to fix SQL lexer, parser

2. requirement to use qualified name everywhere - it can works, but I don't prefer it, because sometimes can be unfunny to write long qualified identifiers. There are not aliases on schema in PLpgSQL. Possible solved by variable aliases. But it requires alias.

3. plpgsql GUC where schema variables are: a) disabled, b) enabled, c) only qualified names are allowed - it is similar to #variable_conflict option

I prefer @3 with "c" as default, but I can live with @2, and dislike @1 due mentioned reasons.

Can you be satisfied by any mentioned variant?

Regards

Pavel
 

That makes absolutely no sense to me at all.


.m

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