Horton

Re: WIP: a way forward on bootstrap data

John Naylor <jcnaylor@gmail.com>

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From: John Naylor <jcnaylor@gmail.com>
To: Mark Dilger <hornschnorter@gmail.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2018-05-06T19:08:43Z
Lists: pgsql-hackers 
On 5/7/18, Mark Dilger <hornschnorter@gmail.com> wrote:
> Hackers,
>
> Have you already considered and rejected the idea of having
> genbki.pl/Catalog.pm define constants that can be used in
> the catalog .dat files?  I'm mostly curious if people think
> the resulting .dat files are better or worse using constants
> of this sort.  For example:
...
> +               # pg_cast constants for castcontext
> +               use constant IMPLICIT => 'i';
> +               use constant ASSIGNMENT => 'a';
> +               use constant EXPLICIT => 'e';

The comment refers to pg_cast, but these constants apply globally.
It's also not the right place from a maintainability perspective, and
if it was, now these values have different macros defined in two
places. This is not good.

> -  castcontext => 'a', castmethod => 'f' },
> +  castcontext => ASSIGNMENT, castmethod => FUNCTION },

For one, this breaks convention that the values are always
single-quoted. If you had a use case for something like this, I would
instead use the existing lookup infrastructure and teach genbki.pl to
parse the enums (or #defines as the case might be) in the relevant
header file. You'd need some improvement in readability to justify
that additional code, though. I don't think this example quite passes
(it's pretty obvious locally what the letters refer to), but others
may feel differently.

-John Naylor

Commits

  1. Clarify handling of special-case values in bootstrap catalog data.

  2. Replace our traditional initial-catalog-data format with a better design.

  3. Faster partition pruning

  4. Minor cleanup in genbki.pl.

  5. Trivial adjustments in preparation for bootstrap data conversion.

  6. Remove hard-coded schema knowledge about pg_attribute from genbki.pl

  7. Minor edits to catalog files and scripts

  8. Hide most variable-length fields from Form_pg_* structs