Horton

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

Danil Anisimow <anisimow.d@gmail.com>

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From: Danil Anisimow <anisimow.d@gmail.com>
To: Damir Belyalov <dam.bel07@gmail.com>
Cc: torikoshia <torikoshia@oss.nttdata.com>, "a.lepikhov@postgrespro.ru" <a.lepikhov@postgrespro.ru>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2022-12-09T14:25:34Z
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

Hi!

I have looked at your patch and have a few questions.

110: static bool SafeCopying(CopyFromState cstate, ExprContext *econtext,
111: TupleTableSlot *myslot);
---
636: bool
637: SafeCopying(CopyFromState cstate, ExprContext *econtext,
TupleTableSlot *myslot)

Why is there no static keyword in the definition of the SafeCopying()
function, but it is in the function declaration.

675: MemoryContext cxt =
MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
676:
677: valid_row = NextCopyFrom(cstate, econtext, myslot->tts_values,
myslot->tts_isnull);
678: tuple_is_valid = valid_row;
679:
680: if (valid_row)
681: sfcstate->safeBufferBytes += cstate->line_buf.len;
682:
683: CurrentMemoryContext = cxt;

Why are you using a direct assignment to CurrentMemoryContext instead of
using the MemoryContextSwitchTo function in the SafeCopying() routine?

1160: /* Standard copying with option "safe copying" enabled by
IGNORE_ERRORS. */
1161: if (!SafeCopying(cstate, econtext, myslot))
1162: break;

I checked with GDB that the CurrentMemoryContext changes when SafeCopying
returns. And the target context may be different each time you do a COPY in
psql.

1879: cstate->sfcstate->safe_cxt = AllocSetContextCreate(oldcontext,
1880: "Safe_context",
1881: ALLOCSET_DEFAULT_SIZES);

When you initialize the cstate->sfcstate structure, you create a
cstate->sfcstate->safe_cxt memory context that inherits from oldcontext.
Was it intended to use cstate->copycontext as the parent context here?

On Wed, Nov 2, 2022 at 11:46 AM Damir Belyalov <dam.bel07@gmail.com> wrote:

> Updated the patch:
> - Optimized and simplified logic of IGNORE_ERRORS
> - Changed variable names to more understandable ones
> - Added an analogue of MAX_BUFFERED_BYTES for safe buffer
>
>
> Regards,
> Damir Belyalov
> Postgres Professional
>

Regards,
Daniil Anisimov
Postgres Professional