Fix 'AT TIME ZONE' issue near DST change time with DATETIME2 datatype…

… conversion. (#3347) Convert function when converting to datetime2, datetime, smalldatettime with given timezone using AT TIME ZONE gives wrong output near DST change time. Fix timestamp value to consider it in the given timezone instead of UTC for datetime2, datetime, smalldatettime datatypes. This fixes the issue and also makes it independent of local timezone setting. Task: BABEL-5513 Signed-off-by: Anikait Agrawal <[email protected]>
babelfish-for-postgresql · Jan 3, 2025 · fbe64c3 · fbe64c3
1 parent 7b3e322
commit fbe64c3
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diff --git a/contrib/babelfishpg_tsql/sql/sys_functions.sql b/contrib/babelfishpg_tsql/sql/sys_functions.sql
@@ -1116,9 +1116,7 @@ DECLARE
     tz_offset PG_CATALOG.TEXT;
     tz_name PG_CATALOG.TEXT;
     lower_tzn PG_CATALOG.TEXT;
-    prev_res PG_CATALOG.TEXT;
     result PG_CATALOG.TEXT;
-    is_dstt bool;
     tz_diff PG_CATALOG.TEXT;
     input_expr_tx PG_CATALOG.TEXT;
     input_expr_tmz TIMESTAMPTZ;
@@ -1139,31 +1137,25 @@ BEGIN
     END IF;
 
     IF pg_typeof(input_expr) IN ('sys.smalldatetime'::regtype, 'sys.datetime'::regtype, 'sys.datetime2'::regtype) THEN
-        input_expr_tx := input_expr::TEXT;
-        input_expr_tmz := input_expr_tx :: TIMESTAMPTZ;
-
-        tz_diff := (SELECT input_expr_tmz AT TIME ZONE tz_name - input_expr_tmz AT TIME ZONE 'UTC')::TEXT;
-        if PG_CATALOG.LEFT(tz_diff,1) <> '-' THEN
-            tz_diff := PG_CATALOG.concat('+',tz_diff);
-        END IF;
-        tz_offset := PG_CATALOG.left(tz_diff,6);
-        input_expr_tx := PG_CATALOG.concat(input_expr_tx,tz_offset);
-        return cast(input_expr_tx as sys.datetimeoffset);
+        input_expr_tx := input_expr::TEXT || ' ' || tz_name;
     ELSIF  pg_typeof(input_expr) = 'sys.DATETIMEOFFSET'::regtype THEN
         input_expr_tx := input_expr::TEXT;
-        input_expr_tmz := input_expr_tx :: TIMESTAMPTZ;
-        result := (SELECT input_expr_tmz  AT TIME ZONE tz_name)::TEXT;
-        tz_diff := (SELECT input_expr_tmz AT TIME ZONE tz_name - input_expr_tmz AT TIME ZONE 'UTC')::TEXT;
-        if PG_CATALOG.LEFT(tz_diff,1) <> '-' THEN
-            tz_diff := PG_CATALOG.concat('+',tz_diff);
-        END IF;
-        tz_offset := PG_CATALOG.left(tz_diff,6);
-        result := PG_CATALOG.concat(result,tz_offset);
-        return cast(result as sys.datetimeoffset);
     ELSE
         RAISE USING MESSAGE := 'Argument data type varchar is invalid for argument 1 of AT TIME ZONE function.'; 
     END IF;
-
+
+    input_expr_tmz := input_expr_tx :: TIMESTAMPTZ;
+    result := (SELECT input_expr_tmz  AT TIME ZONE tz_name)::TEXT;
+    tz_diff := (SELECT input_expr_tmz AT TIME ZONE tz_name - input_expr_tmz AT TIME ZONE 'UTC')::TEXT;
+
+    if PG_CATALOG.LEFT(tz_diff,1) <> '-' THEN
+        tz_diff := PG_CATALOG.concat('+',tz_diff);
+    END IF;
+
+    tz_offset := PG_CATALOG.left(tz_diff,6);
+    result := PG_CATALOG.concat(result,tz_offset);
+
+    return cast(result as sys.datetimeoffset);
 END;
 $BODY$
 LANGUAGE 'plpgsql' STABLE;

diff --git a/contrib/babelfishpg_tsql/sql/upgrades/babelfishpg_tsql--3.8.0--3.9.0.sql b/contrib/babelfishpg_tsql/sql/upgrades/babelfishpg_tsql--3.8.0--3.9.0.sql
@@ -8449,9 +8449,7 @@ DECLARE
     tz_offset PG_CATALOG.TEXT;
     tz_name PG_CATALOG.TEXT;
     lower_tzn PG_CATALOG.TEXT;
-    prev_res PG_CATALOG.TEXT;
     result PG_CATALOG.TEXT;
-    is_dstt bool;
     tz_diff PG_CATALOG.TEXT;
     input_expr_tx PG_CATALOG.TEXT;
     input_expr_tmz TIMESTAMPTZ;
@@ -8472,31 +8470,25 @@ BEGIN
     END IF;
 
     IF pg_typeof(input_expr) IN ('sys.smalldatetime'::regtype, 'sys.datetime'::regtype, 'sys.datetime2'::regtype) THEN
-        input_expr_tx := input_expr::TEXT;
-        input_expr_tmz := input_expr_tx :: TIMESTAMPTZ;
-
-        tz_diff := (SELECT input_expr_tmz AT TIME ZONE tz_name - input_expr_tmz AT TIME ZONE 'UTC')::TEXT;
-        if PG_CATALOG.LEFT(tz_diff,1) <> '-' THEN
-            tz_diff := PG_CATALOG.concat('+',tz_diff);
-        END IF;
-        tz_offset := PG_CATALOG.left(tz_diff,6);
-        input_expr_tx := PG_CATALOG.concat(input_expr_tx,tz_offset);
-        return cast(input_expr_tx as sys.datetimeoffset);
+        input_expr_tx := input_expr::TEXT || ' ' || tz_name;
     ELSIF  pg_typeof(input_expr) = 'sys.DATETIMEOFFSET'::regtype THEN
         input_expr_tx := input_expr::TEXT;
-        input_expr_tmz := input_expr_tx :: TIMESTAMPTZ;
-        result := (SELECT input_expr_tmz  AT TIME ZONE tz_name)::TEXT;
-        tz_diff := (SELECT input_expr_tmz AT TIME ZONE tz_name - input_expr_tmz AT TIME ZONE 'UTC')::TEXT;
-        if PG_CATALOG.LEFT(tz_diff,1) <> '-' THEN
-            tz_diff := PG_CATALOG.concat('+',tz_diff);
-        END IF;
-        tz_offset := PG_CATALOG.left(tz_diff,6);
-        result := PG_CATALOG.concat(result,tz_offset);
-        return cast(result as sys.datetimeoffset);
     ELSE
         RAISE USING MESSAGE := 'Argument data type varchar is invalid for argument 1 of AT TIME ZONE function.'; 
     END IF;
-
+
+    input_expr_tmz := input_expr_tx :: TIMESTAMPTZ;
+    result := (SELECT input_expr_tmz  AT TIME ZONE tz_name)::TEXT;
+    tz_diff := (SELECT input_expr_tmz AT TIME ZONE tz_name - input_expr_tmz AT TIME ZONE 'UTC')::TEXT;
+
+    if PG_CATALOG.LEFT(tz_diff,1) <> '-' THEN
+        tz_diff := PG_CATALOG.concat('+',tz_diff);
+    END IF;
+
+    tz_offset := PG_CATALOG.left(tz_diff,6);
+    result := PG_CATALOG.concat(result,tz_offset);
+
+    return cast(result as sys.datetimeoffset);     
 END;
 $BODY$
 LANGUAGE 'plpgsql' STABLE;