strange parallel query behavior

From: Eric Spear <espear_at_deans.umd.edu>
Date: Tue, 29 Jun 1999 21:50:52 -0400
Message-ID: <377977FB.C872010D@deans.umd.edu>

The text below shows the exact same query. However, the first one is run with one
of the tables in "parallel" mode, while the second query has that table switched to "serial" mode. The first query gets the wrong answer; the second query is correct. Lesson: the parallel option seems a little buggy, yes?

SQL> alter table um_fac_course parallel (degree default);

Table altered.

SQL> select term,
a.indiv_instr_ind
from prodsch.sch_course_faculty a,

       um_fac_course d
where rownum < 9
and a.class_cd = d.class_cd

and    a.indiv_instr_ind = d.indiv_instr_ind
and    a.crs_level_cd = d.crs_level_cd
and    a.lead_class_ind = d.lead_class_ind
and    decode(a.fac_stu_cnt_curr,
             0, 'N', 'Y') = d.has_students_ind

;

  2 3 4 5 6 7 8 9 10 11 12 no rows selected

SQL> alter table um_fac_course noparallel;

Table altered.

SQL> select term,
a.indiv_instr_ind
from prodsch.sch_course_faculty a,

       um_fac_course d
where rownum < 9
and a.class_cd = d.class_cd

and    a.indiv_instr_ind = d.indiv_instr_ind
and    a.crs_level_cd = d.crs_level_cd
and    a.lead_class_ind = d.lead_class_ind
and    decode(a.fac_stu_cnt_curr,
             0, 'N', 'Y') = d.has_students_ind

;

  2 3 4 5 6 7 8 9 10 11 12 TERM I
------ -
199801 N
199801 N
199801 N
199801 N
199801 N
199801 N
199801 N
199801 N

8 rows selected.

SQL> Received on Tue Jun 29 1999 - 20:50:52 CDT