Horton

Re: making the backend's json parser work in frontend code

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: David Steele <david@pgmasters.net>
Cc: Andres Freund <andres@anarazel.de>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2020-01-16T20:44:37Z
Lists: pgsql-hackers 
On Thu, Jan 16, 2020 at 1:58 PM David Steele <david@pgmasters.net> wrote:
> To do page-level incrementals (which this feature is intended to enable)
> the user will need to be able to associate full and incremental backups
> and the only way I see to do that (currently) is to read the manifests,
> since the prior backup should be stored there.  I think this means that
> parsing the manifest is not really optional -- it will be required to do
> any kind of automation with incrementals.

My current belief is that enabling incremental backup will require
extending the manifest format either not at all or by adding one
additional line with some LSN info.

If we could foresee a need to store a bunch of additional *per-file*
details, I'd be a lot more receptive to the argument that we ought to
be using a more structured format like JSON. And it doesn't seem
impossible that such a thing could happen, but I don't think it's at
all clear that it actually will happen, or that it will happen soon
enough that we ought to be worrying about it now.

It's possible that we're chasing a real problem here, and if there's
something we can agree on and get done I'd rather do that than argue,
but I am still quite suspicious that there's no actually serious
technical problem here.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

Commits

  1. Add jsonapi.c to Mkvcbuild.pm's @pgcommonallfiles.

  2. Move jsonapi.c and jsonapi.h to src/common.

  3. Move some code from jsonapi.c to jsonfuncs.c.

  4. Adjust pg_parse_json() so that it does not directly ereport().

  5. Remove jsonapi.c's lex_accept().

  6. Split JSON lexer/parser from 'json' data type support.

  7. Rationalize code placement between wchar.c, encnames.c, and mbutils.c.

  8. Move wchar.c and encnames.c to src/common/.

  9. Update header comments for wchar.c and encnames.c.

  10. Make StringInfo available to frontend code.

  11. Use SASLprep to normalize passwords for SCRAM authentication.