Re: Curing plpgsql's memory leaks for statement-lifespan values

On 22 July 2016 at 07:02, Tom Lane <tgl@sss.pgh.pa.us> wrote:

In
https://www.postgresql.org/message-id/tencent_5C738ECA65BAD6861AA43E8F@qq.com
it was pointed out that you could get an intra-function-call memory leak
from something like

        LOOP
          BEGIN
            EXECUTE 'bogus command';
          EXCEPTION WHEN OTHERS THEN
          END;
        END LOOP;

...
 

Another answer is to invent a third per-function memory context intended
to hold statement-lifespan variables.

I've wanted this in the past and been surprised we don't have it, so +1 from me. 

I don't think a few MemoryContextAlloc's are too ugly.

I suggest that in cassert builds, or maybe just CACHE_CLOBBER_ALWAYS, the context is reset after each call even when not cleaning up after an error. That'll help catch mistakes and leaks.