On Sat, Sep 17, 2016 at 9:41 AM, Heikki Linnakangas <hlinn...@iki.fi> wrote: > Ok. I'll probably read through it myself once more some time next week, and > also have a first look at your actual parallel sorting patch. Have a good > trip!
Thanks! It will be good to get away for a while. I'd be delighted to recruit you to work on the parallel CREATE INDEX patch. I've already explained how I think this preread patch of yours works well with parallel tuplesort (as proposed) in particular. To reiterate: while what you've come up with here is technically an independent improvement to merging, it's much more valuable in the overall context of parallel sort, where disproportionate wall clock time is spent merging, and where multiple passes are the norm (one pass in each worker, plus one big final pass in the leader process alone -- logtape.c fragmentation becomes a real issue). The situation is actually similar to the original batch memory preloading patch that went into 9.6 (which your new patch supersedes), and the subsequently committed quicksort for external sort patch (which my new patch extends to work in parallel). Because I think of your preload patch as a part of the overall parallel CREATE INDEX effort, if that was the limit of your involvement then I'd still think it fair to credit you as my co-author. I hope it isn't the limit of your involvement, though, because it seems likely that the final result will be better still if you get involved with the big patch that formally introduces parallel CREATE INDEX. -- Peter Geoghegan -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers