I reproduced the problem by loading this dump to 8.1.0.
I think that the problem is the same as this:
http://archives.postgresql.org/pgsql-hackers/2005-11/msg01016.php
I saw heap_tuple_toast_attrs() overwrites a new tuple. And, backend
crashed while executing ExecInsertIndexTuples().
The problem occurs by the table like the following structures.(1)The table has a varlena column.(2)The table has a
columnwith check constraint after the varlena column.(3)The table has a indexed column after the column with check
constraint.
And, the problem occurs if a tuple for which TOAST is necessary is
inserted or updated.
Example:
create table test_tbl ( varlena_col text, check_col text, index_col text, constraint
test_tbl_chkcheck (check_col ~ '^[0-9]+$')
);
create index test_tbl_idx on test_tbl(index_col);
insert into test_tbl (varlena_col, check_col, index_col)
values('A', '0', 'B');
update test_tbl
set varlena_col = repeat('A', 2000)
where index_col = 'B';
The backend will be crashed or wrong data will be registered to the index.
If backend is not crashed, Index Scan might return the wrong result.
explain select count(*) from test_tbl where index_col = 'B'; QUERY PLAN
---------------------------------------------------------------------------Aggregate (cost=8.50..8.51 rows=1 width=0)
-> Bitmap Heap Scan on test_tbl (cost=2.01..8.49 rows=3 width=0) Recheck Cond: (index_col = 'B'::text)
-> Bitmap Index Scan on test_tbl_idx (cost=0.00..2.01 rows=3 width=0) Index Cond: (index_col = 'B'::text)
select count(*) from test_tbl where index_col = 'B';count
------- 0 (Wrong result. Correct result is 1.)
--- Atsushi Ogawa
