Horton

Re: COPY FREEZE and setting PD_ALL_VISIBLE/visibility map bits

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: Pavan Deolasee <pavan.deolasee@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>, Jeff Janes <jeff.janes@gmail.com>, Simon Riggs <simon@2ndquadrant.com>, Tomas Vondra <tomas.vondra@2ndquadrant.com>
Date: 2019-04-04T21:45:20Z
Lists: pgsql-hackers 
Hi,

On 2019-04-04 12:23:08 -0700, Andres Freund wrote:
> Also, how is this code even close to correct?
> CheckAndSetPageAllVisible() modifies the buffer in a crucial way, and
> there's no WAL logging? Without even a comment arguing why that's OK (I
> don't think it is)?

Peter Geoghegan just reminded me over IM that there's actually logging
inside log_heap_visible(), called from visibilitymap_set(). Still lacks
a critical section though.

I still think this is the wrong architecture.

Greetings,

Andres Freund

PS: We're going to have to revamp visibilitymap_set() soon-ish - the
fact that it directly calls heap routines inside is bad, means that
additional AMs e.g. zheap has to reimplement that routine.

Commits

  1. Fix COPY FREEZE with CLOBBER_CACHE_ALWAYS

  2. Set PD_ALL_VISIBLE and visibility map bits in COPY FREEZE

  3. docs: client certificates are always sent to the server

  4. Mark commit and abort WAL records with XLR_SPECIAL_REL_UPDATE.

  5. docs: land height is "elevation", not "altitude"

  6. Improve the internal implementation of ereport().