Re: Regression in COPY FROM caused by 9f8377f7a2 - Mailing list pgsql-hackers

From Andrew Dunstan
Subject Re: Regression in COPY FROM caused by 9f8377f7a2
Date
Msg-id b815e4b1-8d8c-1822-ddd0-0a3c8b56c768@dunslane.net
Whole thread Raw
In response to Re: Regression in COPY FROM caused by 9f8377f7a2  (Laurenz Albe <laurenz.albe@cybertec.at>)
Responses Re: Regression in COPY FROM caused by 9f8377f7a2
List pgsql-hackers


On 2023-09-25 Mo 04:59, Laurenz Albe wrote:
On Mon, 2023-09-25 at 09:54 +0200, Laurenz Albe wrote:
In v16 and later, the following fails:

CREATE TABLE boom (t character varying(5) DEFAULT 'a long string');

COPY boom FROM STDIN;
ERROR:  value too long for type character varying(5)

In PostgreSQL v15 and earlier, the COPY statement succeeds.

The error is thrown in BeginCopyFrom in line 1578 (HEAD)

  defexpr = expression_planner(defexpr);

Bisecting shows that the regression was introduced by commit 9f8377f7a2,
which introduced DEFAULT values for COPY FROM.


Oops :-(


I suggest the attached fix, which evaluates default values only if
the DEFAULT option was specified or if the column does not appear in
the column list of COPY.


Patch looks reasonable, haven't tested yet.


cheers


andrew

--
Andrew Dunstan
EDB: https://www.enterprisedb.com

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