"Roberto Caravani" <JFanatiker@gmx.at> writes:
> I have a little problem with a unique constraint:
> create table meta_data (
> id serial primary key,
> type int not null,
> data bytea not null,
> unique (type, data)
> );
> data can be quite large (a few hundred kilo bytes). The unique constraint automatically creates a btree index as I
learnedfrom the documentation. The problem is that I get an error when inserting data, that the index is to large.
You mean that an index entry is too large, because you have a wide
"data" value?
The usual hack for that is to put a unique index on some hash of the
wide column, trusting that you won't get hash collisions. So for
instance
create unique index meta_data_unique on meta_data (type, md5(data));
regards, tom lane
