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 677f2d81-13b2-6f82-c0b4-4163c753c72f@dunslane.net
Whole thread Raw
In response to Re: Regression in COPY FROM caused by 9f8377f7a2  (Andrew Dunstan <andrew@dunslane.net>)
Responses Re: Regression in COPY FROM caused by 9f8377f7a2
List pgsql-hackers


On 2023-09-25 Mo 11:06, Andrew Dunstan wrote:


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.




Thinking about this a little more, wouldn't it be better if we checked at the time we set the default that the value is actually valid for the given column? This is only one manifestation of a problem you could run into given this table definition.


cheers


andrew

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

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