On Tue, May 5, 2020 at 12:50:01PM -0500, Justin Pryzby wrote: > On Tue, May 05, 2020 at 01:18:09PM -0400, Bruce Momjian wrote: > > > |Release date: 2020-05-03 > > > => Should say 2020-XX-XX, before someone like me goes and installs it > > > everywhere in sight. > > > > Agreed! > > > > > |These triggers cannot change the destination partition. > > > => Maybe say "cannot change which partition is the destination" > > Looks like you copied my quote mark :(
I kind of liked it, but OK, removed. ;-) > > > | Allow hash aggregation to use disk storage for large aggregation result > > > sets (Jeff Davis) > > > | Previously, hash aggregation was not used if it was expected to use > > > more than work_mem memory. This is controlled by enable_hashagg_disk. > > > => enable_hashagg_disk doesn't behave like other enable_* parameters. > > > As I understand, disabling it only "opportunisitically" avoids plans > > > which are > > > *expected* to overflow work_mem. I think we should specifically say > > > that, and > > > maybe suggest recalibrating work_mem. > > > > I went with "avoided": > > > > Previously, hash aggregation was avoided if it was expected to use more > > than work_mem memory. This is controlled by enable_hashagg_disk. > > I think we should expand on this: > > |Previously, hash aggregation was avoided if it was expected to use more than > |work_mem memory, but it wasn't enforced, and hashing could still exceed > |work_mem. To get back the old behavior, increasing work_mem. I think work_mem has too many other effects to recommend just changing it for this. > |The parameter enable_hashagg_disk controls whether a plan which is *expected* > |to spill to disk will be considered. During execution, an aggregate node > which > |exceeding work_mem will spill to disk regardless of this parameter. > > I wrote something similar here: > https://www.postgresql.org/message-id/20200407223900.GT2228%40telsasoft.com I think this kind of information should be in our docs, not really the release notes. > > > | This is controlled by GUC wal_skip_threshold. > > > I think you should say that's a size threshold which determines which > > > strategy > > > to use (WAL or fsync). > > > > I went with: > > The WAL write amount where this happens is controlled by > > wal_skip_threshold. > > > > They can use the doc link if they want more detail. > > I guess I would say "relations larger than wal_skip_threshold will be fsynced > rather than copied to WAL" How is this? Relations larger than wal_skip_threshold will have their files fynsced rather than writing their WAL records. -- Bruce Momjian <br...@momjian.us> https://momjian.us EnterpriseDB https://enterprisedb.com + As you are, so once was I. As I am, so you will be. + + Ancient Roman grave inscription +
