* Tom Lane ([EMAIL PROTECTED]) wrote: > "Luke Lonergan" <[EMAIL PROTECTED]> writes: > > I would only suggest that we replace the existing algorithm with one that > > will work regardless of (reasonable) memory requirements. Perhaps we can > > agree that at least 1MB of RAM for external sorting will always be available > > and proceed from there? > > If you can sort indefinitely large amounts of data with 1MB work_mem, > go for it.
It seems you two are talking past each other and I'm at least slightly confused. So, I'd like to ask for a bit of clarification and perhaps that will help everyone. #1: I'm as much a fan of eliminating unnecessary code as anyone #2: There have been claims of two-pass improving things 400% #3: Supposedly two-pass requires on the order of sqrt(total) memory #4: We have planner statistics to estimate size of total #5: We have a work_mem limitation for a reason So, if we get a huge performance increase, what's wrong with: if [ sqrt(est(total)) <= work_mem ]; then two-pass-sort(); else tape-sort(); fi ? If the performance isn't much different and tape-sort can do it with less memory then I don't really see any point in removing it. If the intent is to remove it and then ask for the default work_mem to be increased- I doubt going about it this way would work very well. :) Thanks, Stephen
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