Horton

Re: [BUG]Update Toast data failure in logical replication

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Dilip Kumar <dilipbalaut@gmail.com>, Euler Taveira <euler@eulerto.com>, Michael Paquier <michael@paquier.xyz>, Alvaro Herrera <alvherre@alvh.no-ip.org>, Petr Jelinek <petr.jelinek@enterprisedb.com>, Peter Eisentraut <peter.eisentraut@enterprisedb.com>, Tomas Vondra <tomas.vondra@enterprisedb.com>, Kuntal Ghosh <kuntalghosh.2007@gmail.com>, "tanghy.fnst@fujitsu.com" <tanghy.fnst@fujitsu.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2022-02-05T23:34:45Z
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. WAL log unchanged toasted replica identity key attributes.

  2. Add new wal_level, logical, sufficient for logical decoding.

  3. Add the notion of REPLICA IDENTITY for a table.

Hi,

On 2022-02-04 17:45:36 +0530, Amit Kapila wrote:
> diff --git a/contrib/test_decoding/expected/toast.out b/contrib/test_decoding/expected/toast.out
> index cd03e9d..a757e7d 100644
> --- a/contrib/test_decoding/expected/toast.out
> +++ b/contrib/test_decoding/expected/toast.out
> @@ -77,7 +77,7 @@ SELECT substr(data, 1, 200) FROM pg_logical_slot_get_changes('regression_slot',
>   table public.toasted_key: INSERT: id[integer]:1 toasted_key[text]:'1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123
>   COMMIT
>   BEGIN
> - table public.toasted_key: UPDATE: id[integer]:1 toasted_key[text]:unchanged-toast-datum toasted_col1[text]:unchanged-toast-datum toasted_col2[text]:'987654321098765432109876543210987654321098765432109
> + table public.toasted_key: UPDATE: old-key: toasted_key[text]:'123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678

Hm. This looks weird. What happened to the the change to toasted_col2 that was
in the "removed" line?

This corresponds to the following statement I think:
-- test update of a toasted key without changing it
UPDATE toasted_key SET toasted_col2 = toasted_col1;
which previously was inserted as:
INSERT INTO toasted_key(toasted_key, toasted_col1) VALUES(repeat('1234567890', 200), repeat('9876543210', 200));

so toasted_col2 should have changed from NULL to repeat('9876543210', 200)


Am I misreading something?


Greetings,

Andres Freund