Unexpected Query hang

When running the query below via the JDBC driver the query hangs unexpectedly.

If the field  dmaj_class is removed from the query data is returned immediately.

If the  AND dcm_mstr.dcm__log01 = 1 portion is removed from the query where clause data is returned immediately.

These are not mutually exclusive either one of the above can be removed or both and the query will resolve.

Note that dmaj_class is not part of any index on table dmaj_mstr.

Note that dcm_mstr.dcm__log01 is not part of any index on dcm_mstr table.

SELECT
 dmaj_class,
 dmaj_source
FROM misc.pub.dcm_mstr
INNER JOIN pub.ad_mstr ON ad_mstr.ad_domain = 'DBWAUS' AND ad_mstr.ad_addr = dcm_mstr.dcm_site
INNER JOIN pub.code_mstr ON dcm_source = code_mstr.code_value
INNER JOIN misc.pub.dmaj_mstr ON dcm_group = dmaj_mstr.dmaj_group
WHERE
 code_mstr.code_domain = 'DBWAUS'
 AND code_mstr.code_fldname = 'dcm_source'
 AND dcm_mstr.dcm__log01 = 1