0lai0 commented on code in PR #4154: URL: https://github.com/apache/datafusion-comet/pull/4154#discussion_r3165495472
########## spark/src/test/scala/org/apache/comet/parquet/ParquetInt96NtzCorrectnessSuite.scala: ########## @@ -0,0 +1,82 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +package org.apache.comet.parquet + +import java.sql.Timestamp +import java.time.LocalDateTime + +import org.apache.spark.SparkException +import org.apache.spark.sql.CometTestBase +import org.apache.spark.sql.internal.SQLConf + +import org.apache.comet.CometConf + +/** + * Demonstrates the correctness issue tracked in + * https://github.com/apache/datafusion-comet/issues/3720: when a Parquet file stores timestamps + * as INT96 (Spark's TimestampType, UTC-adjusted local-time semantics) and the read schema + * requests TimestampNTZ, the `native_datafusion` scan silently returns wall-clock values that + * disagree with what was written. Spark itself raises (SPARK-36182) to prevent the silent + * reinterpretation. + */ +class ParquetInt96NtzCorrectnessSuite extends CometTestBase { + import testImplicits._ + + test("INT96 TimestampType read as TimestampNTZ silently returns wrong values") { + val sessionTz = "America/Los_Angeles" + val written = "2020-01-01 12:00:00" + + withSQLConf( + SQLConf.SESSION_LOCAL_TIMEZONE.key -> sessionTz, + SQLConf.PARQUET_OUTPUT_TIMESTAMP_TYPE.key -> "INT96", + SQLConf.USE_V1_SOURCE_LIST.key -> "parquet") { + withTempPath { dir => + val path = dir.getCanonicalPath + + // Write "2020-01-01 12:00:00" America/Los_Angeles as INT96. The bits encode + // the UTC instant 2020-01-01 20:00:00; reading back as TimestampType applies + // session-TZ adjustment to recover the original local wall-clock value. + Seq(Timestamp.valueOf(written)).toDF("ts").write.parquet(path) + + // Reference behavior: Spark refuses to read INT96 as TimestampNTZ + // (SPARK-36182) because it cannot safely reinterpret an LTZ instant as NTZ. + withSQLConf(CometConf.COMET_ENABLED.key -> "false") { + intercept[SparkException] { + spark.read.schema("ts timestamp_ntz").parquet(path).collect() + } + } + + // native_datafusion does not refuse; it silently returns a value that + // disagrees with the wall-clock value originally written. This is the + // correctness issue the safety-check fallback is intended to prevent. + withSQLConf(CometConf.COMET_NATIVE_SCAN_IMPL.key -> CometConf.SCAN_NATIVE_DATAFUSION) { + val rows = spark.read.schema("ts timestamp_ntz").parquet(path).collect() + assert(rows.length == 1) + val actual = rows.head.getAs[LocalDateTime](0) + assert( + actual != LocalDateTime.parse("2020-01-01T12:00:00"), + s"native_datafusion returned the original wall-clock value $actual; " + Review Comment: Thanks @andygrove . It looks like the strings on lines 75-76 have an s prefix but don't contain any variables. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
