Maxim Gekk created SPARK-31672:
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Summary: Reading wrong timestamps from dictionary encoded columns
in Parquet files
Key: SPARK-31672
URL: https://issues.apache.org/jira/browse/SPARK-31672
Project: Spark
Issue Type: Sub-task
Components: SQL
Affects Versions: 3.0.0, 3.1.0
Reporter: Maxim Gekk
Assignee: Maxim Gekk
Fix For: 3.0.0
Write dates with dictionary encoding enabled to parquet files:
{code:scala}
Welcome to
____ __
/ __/__ ___ _____/ /__
_\ \/ _ \/ _ `/ __/ '_/
/___/ .__/\_,_/_/ /_/\_\ version 3.1.0-SNAPSHOT
/_/
Using Scala version 2.12.10 (OpenJDK 64-Bit Server VM, Java 1.8.0_242)
Type in expressions to have them evaluated.
Type :help for more information.
scala> spark.conf.set("spark.sql.legacy.parquet.rebaseDateTimeInWrite.enabled",
true)
scala> :paste
// Entering paste mode (ctrl-D to finish)
Seq.tabulate(8)(_ => "1001-01-01").toDF("dateS")
.select($"dateS".cast("date").as("date"))
.repartition(1)
.write
.option("parquet.enable.dictionary", true)
.mode("overwrite")
.parquet("/Users/maximgekk/tmp/parquet-date-dict")
// Exiting paste mode, now interpreting.
{code}
Read them back:
{code:scala}
scala> spark.read.parquet("/Users/maximgekk/tmp/parquet-date-dict").show(false)
+----------+
|date |
+----------+
|1001-01-07|
|1001-01-07|
|1001-01-07|
|1001-01-07|
|1001-01-07|
|1001-01-07|
|1001-01-07|
|1001-01-07|
+----------+
{code}
*Expected values must be 1000-01-01.*
I checked that the date column is encoded by dictionary via:
{code}
➜ parquet-date-dict java -jar ~/Downloads/parquet-tools-1.12.0.jar dump
./part-00000-84a77214-0c8c-45e9-ac41-5ca863b9dd94-c000.snappy.parquet
row group 0
--------------------------------------------------------------------------------
date: INT32 SNAPPY DO:0 FPO:4 SZ:74/70/0.95 VC:8 ENC:BIT_PACKED,RLE,P [more]...
date TV=8 RL=0 DL=1 DS: 1 DE:PLAIN_DICTIONARY
----------------------------------------------------------------------------
page 0: DLE:RLE RLE:BIT_PACKED VLE:PLAIN_DICTIONARY
[more]... VC:8
INT32 date
--------------------------------------------------------------------------------
*** row group 1 of 1, values 1 to 8 ***
value 1: R:0 D:1 V:1001-01-07
value 2: R:0 D:1 V:1001-01-07
value 3: R:0 D:1 V:1001-01-07
value 4: R:0 D:1 V:1001-01-07
value 5: R:0 D:1 V:1001-01-07
value 6: R:0 D:1 V:1001-01-07
value 7: R:0 D:1 V:1001-01-07
value 8: R:0 D:1 V:1001-01-07
{code}
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