On Tuesday 17 June 2014 at 02:37:16, Edward Shishkin wrote: > > [...] > > Yup, blocknr sets minimize memory consumption and are unsortable... > > I think that the cleanest option will be using lists (instead of blocknr > sets) for > the delete sets, if the discard is turned on. It will reduce memory > consumption > by 20%. Indeed, every entry in a blocknr_set occupies ~8 bytes (assuming > that everything is pretty fragmented because of txmod=wa), whereas a list > entry occupies 32 bytes (start, length, plus 2 pointers for the link). > > In this option we'll need to join lists (instead of merging blocknr > sets) during > atoms fusion and apply the list (instead of blocknr set) to the COMMIT > BITMAP > at pre_commit_hook(). I think it won't be a problem, since the lists are > simpler > than blocknr sets. That's a neat approach. I think I'll use unions and do the decision at runtime. -- Ivan Shapovalov / intelfx / > > The next option is to leave everything as is.
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