Re: Why does the PL/pgSQL compiler do this?

I'm still a bit confused. If I replace the ROLLBACK; command with ELEPHANT;
the result is a syntax error. Why doesn't ROLLBACK; produce the same error
since it is not valid in the LANGUAGE plpgsql. I understand that "ROLLBACK
TO SAVEPOINT" IS valid. But it's not the same thing.

On Mon, Oct 31, 2016 at 3:55 PM, Michael Moore <michaeljmoore(at)gmail(dot)com>
wrote:

> Cool, thanks David, I'll give it a read.
>
>
> On Mon, Oct 31, 2016 at 3:24 PM, David G. Johnston <
> david(dot)g(dot)johnston(at)gmail(dot)com> wrote:
>
>> On Mon, Oct 31, 2016 at 3:13 PM, Michael Moore <michaeljmoore(at)gmail(dot)com>
>> wrote:
>>
>>> Here is the complete function, but all you need to look at is the
>>> exception block. (I didn't write this code) :-) I will ask the question
>>> after the code.
>>> ​[...]​
>>>
>>> RETURN TRUE;
>>>
>>> EXCEPTION WHEN OTHERS THEN
>>>
>>> RAISE EXCEPTION '% %', SQLERRM, SQLSTATE;
>>>
>>> ROLLBACK;
>>>
>>> RETURN FALSE;
>>>
>>> END;
>>>
>>> $BODY$
>>>
>>> LANGUAGE plpgsql VOLATILE
>>>
>>> COST 100;
>>>
>>>
>>> So, here is the question. Why does the compiler not catch:
>>>
>>> 1) ROLLBACK; is not a valid PL/pgSQL command
>>>
>>
>> R
>> ​eading section ​41.10.2 at the linked page should answer this part.
>>
>> https://www.postgresql.org/docs/current/static/plpgsql-imple
>> mentation.html
>>
>>
>>> 2) ROLLBACK; and RETURN FALSE; can never be reached
>>>
>>>
>>>
>> Similar to the above - though "static analysis" is yet a step beyond even
>> what the syntax checking skipping covered above would reveal.
>>
>> ​David J.​
>>
>>
>