On Tue, Sep 6, 2016 at 2:46 PM, Peter Geoghegan <p...@heroku.com> wrote: > Feel free to make a counter-proposal for a cap. I'm not attached to > 500. I'm mostly worried about blatant waste with very large workMem > sizings. Tens of thousands of tapes is just crazy. The amount of data > that you need to have as input is very large when workMem is big > enough for this new cap to be enforced.
If tuplesort callers passed a hint about the number of tuples that would ultimately be sorted, and (for the sake of argument) it was magically 100% accurate, then theoretically we could just allocate the right number of tapes up-front. That discussion is a big can of worms, though. There are of course obvious disadvantages that come with a localized cost model, even if you're prepared to add some "slop" to the allocation size or whatever. -- Peter Geoghegan -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
