Re: [PATCH] Compression dictionaries for JSONB

On Wed, 17 Jan 2024 at 19:52, Aleksander Alekseev
<aleksander@timescale.com> wrote:
>
> Hi Shubham,
>
> > > > 8272749e added a few more arguments to CastCreate(). Here is the rebased patch.
> > >
> > > After merging afbfc029 [1] the patch needed a rebase. PFA v10.
> > >
> > > The patch is still in a PoC state and this is exactly why comments and
> > > suggestions from the community are most welcome! Particularly I would
> > > like to know:
> > >
> > > 1. Would you call it a wanted feature considering the existence of
> > > Pluggable TOASTer patchset which (besides other things) tries to
> > > introduce type-aware TOASTers for EXTERNAL attributes? I know what
> > > Simon's [2] and Nikita's latest answers were, and I know my personal
> > > opinion on this [3][4], but I would like to hear from the rest of the
> > > community.
> > >
> > > 2. How should we make sure a dictionary will not consume all the
> > > available memory? Limiting the amount of dictionary entries to pow(2,
> > > 16) and having dictionary versions seems to work OK for ZSON. However
> > > it was pointed out that this may be an unwanted limitation for the
> > > in-core implementation.
> > >
> > > [1]:
https://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=c727f511;hp=afbfc02983f86c4d71825efa6befd547fe81a926
> > > [2]: https://www.postgresql.org/message-id/CANbhV-HpCF852WcZuU0wyh1jMU4p6XLbV6rCRkZpnpeKQ9OenQ%40mail.gmail.com
> > > [3]:
https://www.postgresql.org/message-id/CAJ7c6TN-N3%3DPSykmOjmW1EAf9YyyHFDHEznX-5VORsWUvVN-5w%40mail.gmail.com
> > > [4]:
https://www.postgresql.org/message-id/CAJ7c6TO2XTTk3cu5w6ePHfhYQkoNpw7u1jeqHf%3DGwn%2BoWci8eA%40mail.gmail.com
> >
> > I tried to apply the patch but it is failing at the Head. It is giving
> > the following error:
>
> Yes it does for a while now. Until we reach any agreement regarding
> questions (1) and (2) personally I don't see the point in submitting
> rebased patches. We can continue the discussion but mark the CF entry
> as RwF for now it will be helpful.

Thanks. I have updated the status to "Returned with feedback". Feel
free to create a new entry after we agree on the approach to take it
forward.

Regards,
Vignesh