Parsed test spec with 2 sessions starting permutation: s1b s1d s2b s2i s1c s2c step s1b: begin; step s1d: delete from ppk where a = 1; step s2b: begin; step s2i: insert into pfk values (1); step s1c: commit; step s2i: <... completed> ERROR: insert or update on table "pfk1" violates foreign key constraint "pfk_a_fkey" step s2c: commit; starting permutation: s1b s1d s2bs s2i s1c s2c step s1b: begin; step s1d: delete from ppk where a = 1; step s2bs: begin isolation level serializable; select 1; ?column? -------- 1 (1 row) step s2i: insert into pfk values (1); step s1c: commit; step s2i: <... completed> ERROR: could not serialize access due to concurrent update step s2c: commit; starting permutation: s1b s2b s1d s2i s1c s2c step s1b: begin; step s2b: begin; step s1d: delete from ppk where a = 1; step s2i: insert into pfk values (1); step s1c: commit; step s2i: <... completed> ERROR: insert or update on table "pfk1" violates foreign key constraint "pfk_a_fkey" step s2c: commit; starting permutation: s1b s2bs s1d s2i s1c s2c step s1b: begin; step s2bs: begin isolation level serializable; select 1; ?column? -------- 1 (1 row) step s1d: delete from ppk where a = 1; step s2i: insert into pfk values (1); step s1c: commit; step s2i: <... completed> ERROR: could not serialize access due to concurrent update step s2c: commit; starting permutation: s1b s2b s2i s1d s2c s1c step s1b: begin; step s2b: begin; step s2i: insert into pfk values (1); step s1d: delete from ppk where a = 1; step s2c: commit; step s1d: <... completed> ERROR: update or delete on table "ppk1" violates foreign key constraint "pfk_a_fkey1" on table "pfk" step s1c: commit; starting permutation: s1b s2bs s2i s1d s2c s1c step s1b: begin; step s2bs: begin isolation level serializable; select 1; ?column? -------- 1 (1 row) step s2i: insert into pfk values (1); step s1d: delete from ppk where a = 1; step s2c: commit; step s1d: <... completed> ERROR: update or delete on table "ppk1" violates foreign key constraint "pfk_a_fkey1" on table "pfk" step s1c: commit;