Re: uniqueness not always correct

This bug appears to still exist in 7.0:

    test=> create table test (zone int4, net cidr, unique(zone, net));
    NOTICE:  CREATE TABLE/UNIQUE will create implicit index 'test_zone_key'
    for table 'test'
    CREATE
    test=> insert into test (zone, net) values (1, '1.2.3/24');
    INSERT 22157 1
    test=> insert into test (zone, net) values (1, '2.3.4/24');
    INSERT 22158 1
    test=> select * from test;
     zone |   net
    ------+----------
        1 | 1.2.3/24
        1 | 2.3.4/24
    (2 rows)

    test=> insert into test (zone, net) values (1, '2.3.4/24');
    INSERT 22159 1
    test=>


> Solaris 2.6/sparc; postgres 6.5.1
>
> dns=> create table test (zone int4, net cidr, unique(zone, net));
> NOTICE:  CREATE TABLE/UNIQUE will create implicit index 'test_zone_key' for table 'test'
> CREATE
> dns=> insert into test (zone, net) values (1, '1.2.3/24');
> INSERT 21750 1
> dns=> insert into test (zone, net) values (1, '2.3.4/24');
> INSERT 21751 1
> dns=> insert into test (zone, net) values (1, '1.2.3/24');
> INSERT 21752 1
> dns=> insert into test (zone, net) values (1, '2.3.4/24');
> ERROR:  Cannot insert a duplicate key into a unique index
> dns=> select * from test;
> zone|net
> - ----+--------
>    1|1.2.3/24
>    1|2.3.4/24
>    1|1.2.3/24
> (3 rows)
>
>
> Once a unique error is reported, uniqueness seems to be maintained.
> Also, if you enter 4 values, then try a duplicate, it all works.
>
> The threshold seems to be 3.
>
> A select before the duplicate add also seems to fix it.
>
> ~f
>
>
>
> ************
>
>


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