Peter, Thanks for your feedback. I'm happy to change the name of the tunable or to update the man page in any way. I have already posted an updated patch with changes to the man page which I think may address your concerns there, but please let me know if that still needs more work. It looks like Kyotaro already did some exploration, and tuning the min/max for the WAL size won't solve this problem. Just let me know if there is anything else here which you think I should look into.
Thanks again, Jerry On Tue, Jul 17, 2018 at 1:12 PM, Peter Eisentraut < peter.eisentr...@2ndquadrant.com> wrote: > On 17.07.18 00:04, Jerry Jelinek wrote: > > There have been quite a few comments since last week, so at this point I > > am uncertain how to proceed with this change. I don't think I saw > > anything concrete in the recent emails that I can act upon. > > The outcome of this could be multiple orthogonal patches that affect the > WAL file allocation behavior somehow. I think your original idea of > skipping recycling on a COW file system is sound. But I would rather > frame the option as "preallocating files is obviously useless on a COW > file system" rather than "this will make things mysteriously faster with > uncertain trade-offs". > > The actual implementation could use another round of consideration. I > wonder how this should interact with min_wal_size. Wouldn't > min_wal_size = 0 already do what we need (if you could set it to 0, > which is currently not possible)? Should the new setting be something > like min_wal_size = -1? Or even if it's a new setting, it might be > better to act on it in XLOGfileslop(), so these things are kept closer > together. > > -- > Peter Eisentraut http://www.2ndQuadrant.com/ > PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services >
