Horton

Re: POC PATCH: copy from ... exceptions to: (was Re: VLDB Features)

jian he <jian.universality@gmail.com>

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From: jian he <jian.universality@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Daniel Gustafsson <daniel@yesql.se>, Damir <dam.bel07@gmail.com>, torikoshia <torikoshia@oss.nttdata.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>, Andres Freund <andres@anarazel.de>, anisimow.d@gmail.com, HukuToc@gmail.com, Andrey Lepikhov <a.lepikhov@postgrespro.ru>, Alena Rybakina <lena.ribackina@yandex.ru>
Date: 2023-11-16T00:00:00Z
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. doc: Fix COPY ON_ERROR option syntax synopsis.

  2. Disallow specifying ON_ERROR option without value.

  3. Rename COPY option from SAVE_ERROR_TO to ON_ERROR

  4. Fix spelling in notice

  5. Add new COPY option SAVE_ERROR_TO

On Thu, Nov 9, 2023 at 4:12 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> Daniel Gustafsson <daniel@yesql.se> writes:
> >> On 8 Nov 2023, at 19:18, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> >> I think an actually usable feature of this sort would involve
> >> copying all the failed lines to some alternate output medium,
> >> perhaps a second table with a TEXT column to receive the original
> >> data line.  (Or maybe an array of text that could receive the
> >> broken-down field values?)  Maybe we could dump the message info,
> >> line number, field name etc into additional columns.
>
> > I agree that the errors should be easily visible to the user in some way.  The
> > feature is for sure interesting, especially in data warehouse type jobs where
> > dirty data is often ingested.
>
> I agree it's interesting, but we need to get it right the first time.
>
> Here is a very straw-man-level sketch of what I think might work.
> The option to COPY FROM looks something like
>
>         ERRORS TO other_table_name (item [, item [, ...]])
>
> where the "items" are keywords identifying the information item
> we will insert into each successive column of the target table.
> This design allows the user to decide which items are of use
> to them.  I envision items like
>
> LINENO  bigint          COPY line number, counting from 1
> LINE    text            raw text of line (after encoding conversion)
> FIELDS  text[]          separated, de-escaped string fields (the data
>                         that was or would be fed to input functions)
> FIELD   text            name of troublesome field, if field-specific
> MESSAGE text            error message text
> DETAIL  text            error message detail, if any
> SQLSTATE text           error SQLSTATE code
>

just
SAVE ERRORS

automatically create a table to hold the error. (validate
auto-generated table name uniqueness, validate create privilege).
and the table will have the above related info. if no error then table
gets dropped.