[Haskell-cafe] Possibility to implant Haskell GC into PostgreSQL interesting?

Nick Rudnick joerg.rudnick at t-online.de
Wed Feb 23 01:25:10 CET 2011

Dear all,

recently, at an email conversation with pgsql hackers I had a quick 
shot, asking about their position to somebody replacing their palloc GC 
-- having roughly in mind that either here or on a Mercury mailing list 
(where there's a similar case with a pure declarative language and a 
Boehm GC), where there was a conclusion a non-pure GC would be a major 
hindrance to deeper interaction.

Ok, I found the answer worth a discussion here; as far as I understood, 
they don't oppose the idea that the PostgreSQL GC might be a candidate 
for an update. I see three issues:

(a) The most open question to me is the gain from the Haskell 
perspective; most critical: Would a Haskell GC inside PostgreSQL mean a 
significant change or rather a drop in the bucket? Once this may be 
answered optimistically, there comes the question about possible 
applications -- i.e., what can be done with such a DBMS system. Knowing 
about efforts like (http://groups.inf.ed.ac.uk/links/) I would like to 
let this open for discussion.

Let me please drop here a quote that I believe their object relational 
efforts seem to have gotten stuck at PostgreSQL due to the conceptual 
clash of OO with the relational algebra underlying PostgreSQL -- which 
in turn seems to harmonize much better with Hindley-Milner & Co. (System 

(b) The question I personally can say least about are the expenditures 
to be expected for a such project. I would be very interested in some 
statements. I have limited knowledge about the PostgreSQL GC and would 
assume it is much simpler than, e.g. the GHC GC.

(c) Gain from PostgreSQL perspective: This IMO should be answered 
easiest, hoping the Haskell GC experts to be able to answer easily how 
much is the overhead to be payed for pure declarativity, and the chances 
(e.g. parallelism, multi cores??), too.

Besides it might be interesting to see inhowfar a considerable overhead 
problem may be alleviated by a 'plugin' architecture allowing future 
PostgreSQL users to switch between a set of GCs.

I would be very interested about any comments, Cheers, Nick

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