Horton

Re: storing an explicit nonce

Neil Chen <carpenter.nail.cz@gmail.com>

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From: Neil Chen <carpenter.nail.cz@gmail.com>
To: Bruce Momjian <bruce@momjian.us>
Cc: Robert Haas <robertmhaas@gmail.com>, Stephen Frost <sfrost@snowman.net>, Andres Freund <andres@anarazel.de>, Alvaro Herrera <alvherre@alvh.no-ip.org>, Masahiko Sawada <sawada.mshk@gmail.com>, Tom Kincaid <tomjohnkincaid@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>, Thomas Munro <thomas.munro@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>, Masahiko Sawada <masahiko.sawada@2ndquadrant.com>
Date: 2021-05-27T09:45:21Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Rethink method for assigning OIDs to the template0 and postgres DBs.

  2. pg_upgrade: Preserve database OIDs.

  3. pg_upgrade: Preserve relfilenodes and tablespace OIDs.

  4. Fix for new Boolean node

  5. Improve error handling of HMAC computations

  6. Add macro RelationIsPermanent() to report relation permanence

  7. Enhance nbtree index tuple deletion.

Greetings,

On Thu, May 27, 2021 at 4:52 PM Bruce Momjian <bruce@momjian.us> wrote:

> >
> > I am confused why checksums, which are widely used, acceptably require
> > wal_log_hints, but there is concern that file encryption, which is
> > heavier, cannot acceptably require wal_log_hints.  I must be missing
> > something.
> >
> > Why can't checksums also throw away hint bit changes like you want to do
> > for file encryption and not require wal_log_hints?
>
>
I'm really confused about it, too. I read the above communication, not sure
if my understanding is correct... What we are facing is not only the change
of flag such as *pd_flags*, but also others like pointer array changes in
btree like Robert said. We don't need them to write a WAL record.

I have an immature idea, could we use LSN+blkno+checksum as the nonce when
the checksum enabled? And when the checksum disabled, we just use a
global counter to generate a number as the fake checksum value... Then we
also use LSN+blkno+fake_checksum as the nonce. Is there anything wrong with
that?

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