Re: [PATCH] Compression dictionaries for JSONB

On Wed, Jan 17, 2024 at 4:16 PM Aleksander Alekseev
<aleksander(at)timescale(dot)com> wrote:
>
> Hi hackers,
>
> > 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:
patching file src/test/regress/expected/dict.out
patching file src/test/regress/expected/oidjoins.out
patching file src/test/regress/expected/opr_sanity.out
patching file src/test/regress/parallel_schedule
Hunk #1 FAILED at 111.
1 out of 1 hunk FAILED -- saving rejects to file
src/test/regress/parallel_schedule.rej
patching file src/test/regress/sql/dict.sql
Please send the Re-base version of the patch.

Thanks and Regards,
Shubham Khanna.