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PHILO-HE · Apr 24, 2024 · f3aac93 · f3aac93
1 parent ba8253b
commit f3aac93
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Showing 3 changed files with 41 additions and 8 deletions.
diff --git a/velox/expression/CastExpr.cpp b/velox/expression/CastExpr.cpp
@@ -26,6 +26,7 @@
 #include "velox/expression/ScopedVarSetter.h"
 #include "velox/external/date/tz.h"
 #include "velox/functions/lib/RowsTranslationUtil.h"
+#include "velox/functions/lib/TimeUtils.h"
 #include "velox/type/Type.h"
 #include "velox/vector/ComplexVector.h"
 #include "velox/vector/FunctionVector.h"
@@ -181,11 +182,7 @@ VectorPtr CastExpr::castFromDate(
     case TypeKind::TIMESTAMP: {
       static const int64_t kMillisPerDay{86'400'000};
       const auto& queryConfig = context.execCtx()->queryCtx()->queryConfig();
-      const auto sessionTzName = queryConfig.sessionTimezone();
-      const auto* timeZone =
-          (queryConfig.adjustTimestampToTimezone() && !sessionTzName.empty())
-          ? date::locate_zone(sessionTzName)
-          : nullptr;
+      const auto* timeZone = getTimeZoneFromConfig(queryConfig);
       auto* resultFlatVector = castResult->as<FlatVector<Timestamp>>();
       applyToSelectedNoThrowLocal(context, rows, castResult, [&](int row) {
         auto timestamp = Timestamp::fromMillis(

diff --git a/velox/expression/tests/CastExprTest.cpp b/velox/expression/tests/CastExprTest.cpp
@@ -589,6 +589,26 @@ TEST_F(CastExprTest, stringToTimestamp) {
       std::nullopt,
   };
   testCast<std::string, Timestamp>("timestamp", input, expected);
+
+  setTimezone("GMT-8");
+  testCast<std::string, Timestamp>(
+      "timestamp",
+      {
+          "1970-01-01",
+          "1970-01-01 08:00:00",
+          "1970-01-01 00:00:00",
+          "1970-01-01 08:00:11",
+          "1970-01-01 09:00:00",
+          std::nullopt,
+      },
+      {
+          Timestamp(-28800, 0),
+          Timestamp(0, 0),
+          Timestamp(-28800, 0),
+          Timestamp(11, 0),
+          Timestamp(3600, 0),
+          std::nullopt,
+      });
 }
 
 TEST_F(CastExprTest, timestampToString) {
@@ -2385,8 +2405,8 @@ class TestingDictionaryToFewerRowsFunction : public exec::VectorFunction {
       exec::EvalCtx& context,
       VectorPtr& result) const override {
     const auto size = rows.size();
-    auto indices =
-        makeIndices(size, [](auto /*row*/) { return 0; }, context.pool());
+    auto indices = makeIndices(
+        size, [](auto /*row*/) { return 0; }, context.pool());
 
     result = BaseVector::wrapInDictionary(nullptr, indices, size, args[0]);
   }

diff --git a/velox/functions/lib/TimeUtils.h b/velox/functions/lib/TimeUtils.h
@@ -26,12 +26,28 @@ inline constexpr int64_t kSecondsInDay = 86'400;
 inline constexpr int64_t kDaysInWeek = 7;
 extern const folly::F14FastMap<std::string, int8_t> kDayOfWeekNames;
 
+// Format timezone to make it compatible with date::locate_zone.
+// For example, converts "GMT+8" to "Etc/GMT-8".
+// Here is the list of IANA timezone names:
+// https://en.wikipedia.org/wiki/List_of_tz_database_time_zones
+FOLLY_ALWAYS_INLINE std::string formatTimezone(const std::string& timezone) {
+  if (timezone.find("GMT") == 0 && timezone.size() > 4) {
+    std::string prefix;
+    if (timezone[3] != '+' && timezone[3] != '-') {
+      return timezone;
+    }
+    std::string prefix = timezone[3] == '+' ? "Etc/GMT-" : "Etc/GMT+";
+    return prefix + timezone.substr(4);
+  }
+  return timezone;
+}
+
 FOLLY_ALWAYS_INLINE const date::time_zone* getTimeZoneFromConfig(
     const core::QueryConfig& config) {
   if (config.adjustTimestampToTimezone()) {
     auto sessionTzName = config.sessionTimezone();
     if (!sessionTzName.empty()) {
-      return date::locate_zone(sessionTzName);
+      return date::locate_zone(formatTimezone(sessionTzName));
     }
   }
   return nullptr;