Should I forget about getting such a patch in? I am up for implementing alternative solutions if the current one is considered unacceptable. As I tried to demonstrate in my last email, previous attempts also failed.
On Tue, Sep 3, 2019 at 12:14 PM Swen Kooij <swenko...@gmail.com> wrote: > > I read two previous proposals for something similar. > > First one is from 2013 [0]. It proposed a OS and filesystem specific > implementation. Which was then changed to a patch that adds a > config option to specify shell commands that postgres should use > for copying files and dirs. This was after commentary that such a > feature is better suited for an extension. Which is what I am trying to do. > > What was true in 2013 (when the other patch was proposed) is still > true. There's no good way at the moment to hook into how postgres > copies files and directories. > > The second thread I found from 2018 [1] proposes filesystem specific > changes (BTRFS, APFS and XFS) that operate on a file level. Really > nice patch actually, but much more invasive than what I am proposing. > > > Both patches make rather invasive and significant changes specific > to the features they're trying to build. The general sentiment I got > from reading those two threads is that building in support for these > kind of features is hard and is probably better first done as an extension. > > I understand that the patch I proposed is not an ideal interface, > but it gets the job done without having to built this kind of > functionality into postgres. I am not proposing any filesystem > or OS specific hooks/changes in postgres to make this work. > > I tried to override the copydir() function without any hooks > and I haven't gotten it to work yet. If it does, I'd still prefer the > hook. It's more predictable and probably more portable. > > [0] https://www.postgresql.org/message-id/511b5d11.4040...@socialserve.com > [1] > https://www.postgresql.org/message-id/bc9ca382-b98d-0446-f699-8c5de2307ca7%402ndquadrant.com > > On Tue, Sep 3, 2019 at 9:48 AM Peter Eisentraut > <peter.eisentr...@2ndquadrant.com> wrote: > > > > On 2019-09-02 22:16, Swen Kooij wrote: > > > Is there anything that I am missing? My early experiments have been > > > very promising but my experience with Postgres internals is limited. Any > > > help or feedback would be much appreciated. > > > > You might want to review several previous threads that were > > contemplating doing some reflink stuff with btrfs during database > > creation. Not exactly what you are doing, but related. > > > > Also, wouldn't it work if your extension just defined its own copydir() > > in the .so? That should then be used over the built-in one -- maybe. > > > > -- > > Peter Eisentraut http://www.2ndQuadrant.com/ > > PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
