Zoltán Borók-Nagy created IMPALA-10685:
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Summary: OUTER JOIN against ACID collections might be converted to
INNER JOIN
Key: IMPALA-10685
URL: https://issues.apache.org/jira/browse/IMPALA-10685
Project: IMPALA
Issue Type: Bug
Reporter: Zoltán Borók-Nagy
We are rewriting "A join B" to "A join B1 join B2" for some queries that refer
to collections in ACID tables. This is ok for inner join but may be incorrect
for outer joins. Here is an example, the two queries produce different results:
Query works well for non-ACID table:
{noformat}
impala> with v as (
select ('k4') as key
union all
values ('k1'), ('k2'), ('k3')
) select * from v left join functional_parquet.complextypestbl.int_map using
(key);
+-----+------+-------+
| key | key | value |
+-----+------+-------+
| k1 | k1 | -1 |
| k1 | k1 | 1 |
| k2 | k2 | 100 |
| k1 | k1 | 2 |
| k2 | k2 | NULL |
| k1 | k1 | NULL |
| k3 | k3 | NULL |
| k4 | NULL | NULL |
+-----+------+-------+
Fetched 8 row(s) in 3.35s
{noformat}
LEFT OUTER JOIN converted to INNER JOIN for ACID table:
{noformat}
impala> with v as (
select ('k4') as key
union all
values ('k1'), ('k2'), ('k3')
) select * from v left join functional_orc_def.complextypestbl.int_map using
(key);
+-----+-----+-------+
| key | key | value |
+-----+-----+-------+
| k1 | k1 | -1 |
| k1 | k1 | 1 |
| k2 | k2 | 100 |
| k1 | k1 | 2 |
| k2 | k2 | NULL |
| k1 | k1 | NULL |
| k3 | k3 | NULL |
+-----+-----+-------+
Fetched 7 row(s) in 0.35s
{noformat}
IMPALA-9494 can help to fix this. Until that we could use the techniques from
IMPALA-9330.
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