On Tue, Nov 3, 2015 at 6:37 AM, Simon Riggs <simon@2ndquadrant.com> wrote: > On 3 November 2015 at 15:23, Amit Kapila <amit.kapila16@gmail.com> wrote: >> >> On Fri, Oct 23, 2015 at 6:29 AM, Simon Riggs <simon@2ndquadrant.com> >> wrote: >>> >>> On 21 October 2015 at 13:31, Jeff Janes <jeff.janes@gmail.com> wrote: >>> >>>> Index-only scans will visit the heap for each tuple until the first >>>> VACUUM is done. >>>> >>>> The first vacuum will read the entire table, but not need to write it >>>> anymore. And will create the _vm file. >>>> >>>> I think we really want to create _vm file as well as set PD_ALL_VISIBLE, >>>> but I don't know the best way to do that. Set a flag somewhere and then >>>> create it in bulk at the end of the transaction? Set it bit by bit as the >>>> pages are extended and initialized? >>> >>> >>> Easy enough to do it at the end of the COPY FREEZE in one step. >> >> >> Here, we might want to consider that setting bit in visibility map >> will generate WAL log whereas Copy Freeze otherwise skip WAL >> when wal_level is less than archive. This can lead to extra disk >> writes which can slow down Copy Freeze, but OTOH that might >> be acceptable. > > > I'm building the map as I go, in the latest version of this patch I'm > working on.
Hi Simon,
Is this still on your radar? If you would like someone else to pick it up, can you post the WIP patch you have?
