Kevin Zhang created SPARK-27340:
-----------------------------------
Summary: Alias on TimeWIndow expression may cause watermark
metadata lost
Key: SPARK-27340
URL: https://issues.apache.org/jira/browse/SPARK-27340
Project: Spark
Issue Type: Bug
Components: SQL, Structured Streaming
Affects Versions: 2.4.0
Reporter: Kevin Zhang
When we use data api to write a structured streaming query job we usually
specify a watermark on event time column. If we define a window on the event
time column, the delayKey metadata of the event time column is supposed to be
propagated to the new column generated by time window expression. But if we add
additional alias on the time window column, the delayKey metadata is lost.
Currently I only find the bug will affect stream-stream join. In terms of
aggregation, the gourping expression can be trimed so additional alias are
removed and the metadata is kept.
Here is an example:
{code:scala}
val sparkSession = SparkSession
.builder()
.master("local")
.getOrCreate()
val rateStream = sparkSession.readStream
.format("rate")
.option("rowsPerSecond", 10)
.load()
val fooStream = rateStream
.select(
col("value").as("fooId"),
col("timestamp").as("fooTime")
)
.withWatermark("fooTime", "2 seconds")
.select($"fooId", $"fooTime", window($"fooTime", "2
seconds").alias("fooWindow"))
val barStream = rateStream
// Introduce misses for ease of debugging
.where(col("value") % 2 === 0)
.select(
col("value").as("barId"),
col("timestamp").as("barTime")
)
.withWatermark("barTime", "2 seconds")
.select($"barId", $"barTime", window($"barTime", "2
seconds").alias("barWindow"))
val joinedDf = fooStream
.join(
barStream,
$"fooId" === $"barId" &&
fooStream.col("fooWindow") === barStream.col("barWindow"),
joinType = "LeftOuter"
)
val query = joinedDf
.writeStream
.format("console")
.option("truncate", 100)
.trigger(Trigger.ProcessingTime("5 seconds"))
.start()
query.awaitTermination()
{code}
this program will end with an exception, and from the analyzed plan we can see
there is no delayKey metadata on 'fooWindow'
{code:java}
org.apache.spark.sql.AnalysisException: Stream-stream outer join between two
streaming DataFrame/Datasets is not supported without a watermark in the join
keys, or a watermark on the nullable side and an appropriate range condition;;
Join LeftOuter, ((fooId#4L = barId#14L) && (fooWindow#9 = barWindow#19))
:- Project [fooId#4L, fooTime#5-T2000ms, window#10-T2000ms AS fooWindow#9]
: +- Filter isnotnull(fooTime#5-T2000ms)
: +- Project [named_struct(start, precisetimestampconversion(((((CASE WHEN
(cast(CEIL((cast((precisetimestampconversion(fooTime#5-T2000ms, TimestampType,
LongType) - 0) as double) / cast(2000000 as double))) as double) =
(cast((precisetimestampconversion(fooTime#5-T2000ms, TimestampType, LongType) -
0) as double) / cast(2000000 as double))) THEN
(CEIL((cast((precisetimestampconversion(fooTime#5-T2000ms, TimestampType,
LongType) - 0) as double) / cast(2000000 as double))) + cast(1 as bigint)) ELSE
CEIL((cast((precisetimestampconversion(fooTime#5-T2000ms, TimestampType,
LongType) - 0) as double) / cast(2000000 as double))) END + cast(0 as bigint))
- cast(1 as bigint)) * 2000000) + 0), LongType, TimestampType), end,
precisetimestampconversion((((((CASE WHEN
(cast(CEIL((cast((precisetimestampconversion(fooTime#5-T2000ms, TimestampType,
LongType) - 0) as double) / cast(2000000 as double))) as double) =
(cast((precisetimestampconversion(fooTime#5-T2000ms, TimestampType, LongType) -
0) as double) / cast(2000000 as double))) THEN
(CEIL((cast((precisetimestampconversion(fooTime#5-T2000ms, TimestampType,
LongType) - 0) as double) / cast(2000000 as double))) + cast(1 as bigint)) ELSE
CEIL((cast((precisetimestampconversion(fooTime#5-T2000ms, TimestampType,
LongType) - 0) as double) / cast(2000000 as double))) END + cast(0 as bigint))
- cast(1 as bigint)) * 2000000) + 0) + 2000000), LongType, TimestampType)) AS
window#10-T2000ms, fooId#4L, fooTime#5-T2000ms]
: +- EventTimeWatermark fooTime#5: timestamp, interval 2 seconds
: +- Project [value#1L AS fooId#4L, timestamp#0 AS fooTime#5]
: +- StreamingRelationV2
org.apache.spark.sql.execution.streaming.sources.RateStreamProvider@2cae5fa7,
rate, Map(numPartitions -> 1, rowsPerSecond -> 1), [timestamp#0, value#1L]
+- Project [barId#14L, barTime#15-T2000ms, window#20-T2000ms AS barWindow#19]
+- Filter isnotnull(barTime#15-T2000ms)
+- Project [named_struct(start, precisetimestampconversion(((((CASE WHEN
(cast(CEIL((cast((precisetimestampconversion(barTime#15-T2000ms, TimestampType,
LongType) - 0) as double) / cast(2000000 as double))) as double) =
(cast((precisetimestampconversion(barTime#15-T2000ms, TimestampType, LongType)
- 0) as double) / cast(2000000 as double))) THEN
(CEIL((cast((precisetimestampconversion(barTime#15-T2000ms, TimestampType,
LongType) - 0) as double) / cast(2000000 as double))) + cast(1 as bigint)) ELSE
CEIL((cast((precisetimestampconversion(barTime#15-T2000ms, TimestampType,
LongType) - 0) as double) / cast(2000000 as double))) END + cast(0 as bigint))
- cast(1 as bigint)) * 2000000) + 0), LongType, TimestampType), end,
precisetimestampconversion((((((CASE WHEN
(cast(CEIL((cast((precisetimestampconversion(barTime#15-T2000ms, TimestampType,
LongType) - 0) as double) / cast(2000000 as double))) as double) =
(cast((precisetimestampconversion(barTime#15-T2000ms, TimestampType, LongType)
- 0) as double) / cast(2000000 as double))) THEN
(CEIL((cast((precisetimestampconversion(barTime#15-T2000ms, TimestampType,
LongType) - 0) as double) / cast(2000000 as double))) + cast(1 as bigint)) ELSE
CEIL((cast((precisetimestampconversion(barTime#15-T2000ms, TimestampType,
LongType) - 0) as double) / cast(2000000 as double))) END + cast(0 as bigint))
- cast(1 as bigint)) * 2000000) + 0) + 2000000), LongType, TimestampType)) AS
window#20-T2000ms, barId#14L, barTime#15-T2000ms]
+- EventTimeWatermark barTime#15: timestamp, interval 2 seconds
+- Project [value#1L AS barId#14L, timestamp#0 AS barTime#15]
+- Filter ((value#1L % cast(2 as bigint)) = cast(0 as bigint))
+- StreamingRelationV2
org.apache.spark.sql.execution.streaming.sources.RateStreamProvider@2cae5fa7,
rate, Map(numPartitions -> 1, rowsPerSecond -> 1), [timestamp#0, value#1L]
{code}
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