lincoln lee created FLINK-32578:
-----------------------------------
Summary: Cascaded group by window time columns on a proctime
window aggregate may result hang for ever
Key: FLINK-32578
URL: https://issues.apache.org/jira/browse/FLINK-32578
Project: Flink
Issue Type: Bug
Components: Table SQL / Planner
Affects Versions: 1.17.1
Reporter: lincoln lee
Assignee: lincoln lee
Fix For: 1.18.0, 1.17.2
Currently when group by window time columns on a proctime window aggregate
result will get a wrong plan which may result hang for ever in runtime.
For such a query:
{code}
insert into s1
SELECT
window_start,
window_end,
sum(cnt),
count(*)
FROM (
SELECT
a,
b,
window_start,
window_end,
count(*) as cnt,
sum(d) as sum_d,
max(d) as max_d
FROM TABLE(TUMBLE(TABLE src1, DESCRIPTOR(proctime), INTERVAL '5' MINUTE))
GROUP BY a, window_start, window_end, b
)
GROUP BY a, window_start, window_end
{code}
the inner proctime window works fine, but the outer one doesn't work due to a
wrong plan which will translate to a unexpected event mode window operator:
{code}
Sink(table=[default_catalog.default_database.s1], fields=[ws, we, b, c])
+- Calc(select=[CAST(window_start AS TIMESTAMP(6)) AS ws, CAST(window_end AS
TIMESTAMP(6)) AS we, CAST(EXPR$2 AS BIGINT) AS b, CAST(EXPR$3 AS BIGINT) AS c])
+- WindowAggregate(groupBy=[a], window=[TUMBLE(win_start=[window_start],
win_end=[window_end], size=[5 min])], select=[a, SUM(cnt) AS EXPR$2, COUNT(*)
AS EXPR$3, start('w$) AS window_start, end('w$) AS window_end])
+- Exchange(distribution=[hash[a]])
+- Calc(select=[a, window_start, window_end, cnt])
+- WindowAggregate(groupBy=[a, b],
window=[TUMBLE(time_col=[proctime], size=[5 min])], select=[a, b, COUNT(*) AS
cnt, start('w$) AS window_start, end('w$) AS window_end])
+- Exchange(distribution=[hash[a, b]])
+- Calc(select=[a, b, d, PROCTIME() AS proctime])
+- TableSourceScan(table=[[default_catalog,
default_database, src1, project=[a, b, d], metadata=[]]], fields=[a, b, d])
{code}
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