On Wed, Mar 6, 2019 at 11:02 AM Alvaro Herrera <alvhe...@2ndquadrant.com> wrote:
> On 2019-Mar-06, Robert Haas wrote: > > > On Wed, Mar 6, 2019 at 12:13 PM Alvaro Herrera <alvhe...@2ndquadrant.com> > wrote: > > > I want your dictating software. > > > > I'm afraid this is just me and a keyboard, but sadly for me you're not > > the first person to accuse me of producing giant walls of text. > > Well, I don't have a problem reading long texts; my problem is that I'm > unable to argue as quickly. > > I do buy your argument, though (if reluctantly); in particular I was > worried to offer a parameter (to turn off zero-filling of segments) that > would enable dangerous behavior, but then I realized we also have > fsync=off of which the same thing can be said. So I agree we should > have two GUCs, properly explained, with a warning where appropriate. > > -- > Álvaro Herrera https://www.2ndQuadrant.com/ > PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services > It sounds like everyone is in agreement that I should get rid of the single COW GUC tunable and provide two different tunables instead. I will update the patch to go back to the original name (wal_recycle) for the original WAL recycling behavior. The default value of that will be true to provide the existing behavior. This matches my original proposal from last year. I will add a new tunable (wal_init_zero) which will control the zero-fill behavior for the WAL file. Again, the default value will be true and provide the existing behavior. Both of these could (should) be set to false for a COW filesystem like ZFS. If anyone objects to this new approach, let me know, otherwise I'll start preparing an updated patch. Thanks for all of the feedback, Jerry
