Question

I’m running:
PostgreSQL 9.0.3 (Last Debian stable)

This query:

SELECT * FROM sis.thread_categories
stc, sis.threads st WHERE
st.id_thread_categories=stc.id

=> throws:

ERROR: volatile EquivalenceClass has
no sortref State SQL: XX000

Same problem occured when I’ve tried it using JOIN. Does anybody know what am I doing wrong?

Answer 1

I think you might have a corrupted database, that is not supposed to happen. From backend/optimizer/path/pathkeys.c in the PostgreSQL source:

List *
convert_subquery_pathkeys(PlannerInfo *root, RelOptInfo *rel,
                                                  List *subquery_pathkeys)
{
    /*...*/
            if (sub_eclass->ec_sortref == 0)        /* can't happen */
                elog(ERROR, "volatile EquivalenceClass has no sortref");

That error message shows up in two other places in the source but the triggering condition, ec_sortref == 0, is the same and the same “can’t happen” comments appears in all three places.

So either your database is corrupt or you have found a bug in PostgreSQL.