On 14 August 2015 at 17:42, Tom Lane <t...@sss.pgh.pa.us> wrote:
> The simplest fix for this would be to give up on the idea that DO blocks > use private simple_eval_estates, and make them use the shared one. > However, that would result in intra-transaction memory bloat for > transactions executing large numbers of DO blocks; see commit c7b849a89, > which installed that arrangement to begin with. Since that change was > based on a user complaint, this answer doesn't seem appetizing. > ... > Or we could change things so that DO blocks use private cast_hash > hashtables along with their private simple_eval_estates. This would > give up some efficiency (since a DO block would then always need to do > its own cast lookups) but it would be a simple and reliable fix. > > I'm kind of inclined to go with the last choice, but I wonder if anyone > wants to argue differently, or sees another feasible solution. > Not everyone uses large numbers of DO blocks, but casts apply everywhere, right? If the choice is efficiency or memory bloat, can't we choose a point where we switch from one to the other? i.e. use private structures after N uses of the shared structures. -- Simon Riggs http://www.2ndQuadrant.com/ <http://www.2ndquadrant.com/> PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
