Em Fri, 03 Apr 2009 04:23:10 -0300, Itagaki Takahiro <itagaki.takah...@oss.ntt.co.jp> escreveu:
Vlad Arkhipov <arhi...@dc.baikal.ru> wrote:

Is it possible to print which key value is duplicated when 'Duplicate
key value violates unique constraint' occurs? Foreign key violation
error reports such kind of information.

I think it is not difficult from a technical standpoint.
The attached patch adds DETAIL messages to duplicate key value error:

    postgres=# INSERT INTO tbl(pk1, pk2) VALUES ('A', 1);
    ERROR:  duplicate key value violates unique constraint "tbl_pkey"
    DETAIL:  Key (pk1,pk2)=(A,1) already exists.

If no objection, I'd like to submit the patch to the next commit-fest (8.5).

Hi Takahiro, i'm the reviewer of your patch, and the following are my comments about it:

The patch was applied totalty clean to CVS HEAD and compiled in Ubuntu 8.04, Ubuntu 8.10 and AIX 5.3, but failed in follow tests:

src/test/regress/expected/uuid.out
src/test/regress/expected/constraints.out
src/test/regress/expected/create_index.out
src/test/regress/expected/inherit.out
src/test/regress/expected/transactions.out
src/test/regress/expected/arrays.out
src/test/regress/expected/plpgsql.out
src/test/regress/expected/alter_table.out
src/test/regress/expected/tablespace.out

Would be good to modify the outputs to expect a new "DETAIL:" line.

Another comment is that the patch isn't in the standart context form, but unified.

About the feature, it work as expected when I've INSERTed in both single and compound-key or UPDATEd the key values to violates the constraint, also in concurrently transactions. As expected too, when i INSERT or UPDATE the key with a value thath overflow the 512 bytes i'm getting the output as follow:

---
guedes=# INSERT INTO test_dup_char_key VALUES (repeat('x',1024), 'qq');
ERROR: duplicate key value violates unique constraint "test_dup_char_key_pkey"
DETALHE:  Key (...)=(...) already exists.
---

I'm thinking if could be better to shows Key (my_key)=(...) instead Key (...)=(...) -- well, i don't know how much people uses a key with more 512B and how often it is to they don't know wich key it is, (just reading a log, for example) to we consider this important.

On the other hand there is a comment by Tom [1] about "to refactor this so it's not btree-specific, but could be used by other index AMs", so could be better trying to think about this in a way to find another alternative, if it is possible.

[1] http://archives.postgresql.org/pgsql-hackers/2009-04/msg00234.php

Thanks for your patch!

[]s
Dickson S. Guedes
http://pgcon.postgresql.org.br
http://www.postgresql.org.br

--
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers

Reply via email to