Fix casting varchar to timestamp

PHILO-HE · Jan 13, 2025 · 96e2623 · 96e2623
1 parent 88b16ad
commit 96e2623
Show file tree

Hide file tree

Showing 2 changed files with 27 additions and 1 deletion.
diff --git a/velox/functions/sparksql/specialforms/SparkCastHooks.cpp b/velox/functions/sparksql/specialforms/SparkCastHooks.cpp
@@ -31,8 +31,20 @@ SparkCastHooks::SparkCastHooks(const velox::core::QueryConfig& config)
 
 Expected<Timestamp> SparkCastHooks::castStringToTimestamp(
     const StringView& view) const {
-  return util::fromTimestampString(
+  auto conversionResult = util::fromTimestampString(
       view.data(), view.size(), util::TimestampParseMode::kSparkCast);
+  if (conversionResult.hasError()) {
+    return folly::makeUnexpected(conversionResult.error());
+  }
+  auto result = conversionResult.value();
+  // If no timezone information is available in the input string, check if we
+  // should understand it as being at the session timezone, and if so, convert
+  // to GMT.
+  const auto sessionTzName = config_.sessionTimezone();
+  if (!sessionTzName.empty()) {
+    result.toGMT(*tz::locateZone(sessionTzName));
+  }
+  return result;
 }
 
 Expected<Timestamp> SparkCastHooks::castIntToTimestamp(int64_t seconds) const {

diff --git a/velox/functions/sparksql/tests/SparkCastExprTest.cpp b/velox/functions/sparksql/tests/SparkCastExprTest.cpp
@@ -261,6 +261,20 @@ TEST_F(SparkCastExprTest, stringToTimestamp) {
       Timestamp(1426680197, 456000000),
   };
   testCast<std::string, Timestamp>("timestamp", input, expected);
+
+  setTimezone("Asia/Shanghai");
+  testCast<std::string, Timestamp>(
+      "timestamp",
+      {
+          "1970-01-01 00:00:00",
+          "1970-01-01 08:00:00",
+          "1970-01-01 08:00:59",
+      },
+      {
+          Timestamp(-8 * 3600, 0),
+          Timestamp(0, 0),
+          Timestamp(59, 0),
+      });
 }
 
 TEST_F(SparkCastExprTest, intToTimestamp) {