Change default time_zone to None (was "+00:00")

datafusion/common/src/config.rs

@@ -467,9 +467,8 @@ config_namespace! {
 
         /// The default time zone
         ///
-        /// Some functions, e.g. `EXTRACT(HOUR from SOME_TIME)`, shift the underlying datetime
-        /// according to this time zone, and then extract the hour
-        pub time_zone: String, default = "+00:00".into()
+        /// Some functions, e.g. `now` return timestamps in this time zone
+        pub time_zone: Option<String>, default = None
 
         /// Parquet options
         pub parquet: ParquetOptions, default = Default::default()

datafusion/core/tests/expr_api/simplification.rs

@@ -514,7 +514,7 @@ fn multiple_now() -> Result<()> {
     // expect the same timestamp appears in both exprs
     let actual = get_optimized_plan_formatted(plan, &time);
     let expected = format!(
-        "Projection: TimestampNanosecond({}, Some(\"+00:00\")) AS now(), TimestampNanosecond({}, Some(\"+00:00\")) AS t2\n  TableScan: test",
+        "Projection: TimestampNanosecond({}, None) AS now(), TimestampNanosecond({}, None) AS t2\n  TableScan: test",
         time.timestamp_nanos_opt().unwrap(),
         time.timestamp_nanos_opt().unwrap()
     );

datafusion/core/tests/user_defined/user_defined_scalar_functions.rs

@@ -1812,7 +1812,7 @@ async fn test_config_options_work_for_scalar_func() -> Result<()> {
     });
 
     let mut config = SessionConfig::new();
-    config.options_mut().execution.time_zone = "AEST".into();
+    config.options_mut().execution.time_zone = Some("AEST".into());
 
     let ctx = SessionContext::new_with_config(config);
 

datafusion/functions/src/datetime/current_date.rs

@@ -108,7 +108,14 @@ impl ScalarUDFImpl for CurrentDateFunc {
         let days = info
             .execution_props()
             .config_options()
-            .and_then(|config| config.execution.time_zone.parse::<Tz>().ok())
+            .and_then(|config| {
+                config
+                    .execution
+                    .time_zone
+                    .as_ref()
+                    .map(|tz| tz.parse::<Tz>().ok())
+            })
+            .flatten()
             .map_or_else(
                 || datetime_to_days(&now_ts),
                 |tz| {

datafusion/functions/src/datetime/current_time.rs

@@ -104,7 +104,14 @@ impl ScalarUDFImpl for CurrentTimeFunc {
         let nano = info
             .execution_props()
             .config_options()
-            .and_then(|config| config.execution.time_zone.parse::<Tz>().ok())
+            .and_then(|config| {
+                config
+                    .execution
+                    .time_zone
+                    .as_ref()
+                    .map(|tz| tz.parse::<Tz>().ok())
+            })
+            .flatten()
             .map_or_else(
                 || datetime_to_time_nanos(&now_ts),
                 |tz| {
@@ -167,7 +174,11 @@ mod tests {
 
     fn set_session_timezone_env(tz: &str, start_time: DateTime<Utc>) -> MockSimplifyInfo {
         let mut config = datafusion_common::config::ConfigOptions::default();
-        config.execution.time_zone = tz.to_string();
+        config.execution.time_zone = if tz.is_empty() {
+            None
+        } else {
+            Some(tz.to_string())
+        };
         let mut execution_props =
             ExecutionProps::new().with_query_execution_start_time(start_time);
         execution_props.config_options = Some(Arc::new(config));

datafusion/functions/src/datetime/now.rs

@@ -33,7 +33,7 @@ use datafusion_macros::user_doc;
 #[user_doc(
     doc_section(label = "Time and Date Functions"),
     description = r#"
-Returns the current UTC timestamp.
+Returns the current timestamp in the system configured timezone (None by default).
 
 The `now()` return value is determined at query time and will return the same timestamp, no matter when in the query plan the function executes.
 "#,
@@ -58,15 +58,19 @@ impl NowFunc {
         Self {
             signature: Signature::nullary(Volatility::Stable),
             aliases: vec!["current_timestamp".to_string()],
-            timezone: Some(Arc::from("+00")),
+            timezone: None,
         }
     }
 
     pub fn new_with_config(config: &ConfigOptions) -> Self {
         Self {
             signature: Signature::nullary(Volatility::Stable),
             aliases: vec!["current_timestamp".to_string()],
-            timezone: Some(Arc::from(config.execution.time_zone.as_str())),
+            timezone: config
+                .execution
+                .time_zone
+                .as_ref()
+                .map(|tz| Arc::from(tz.as_str())),
         }
     }
 }

datafusion/sql/src/planner.rs

@@ -693,7 +693,7 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
                     // Timestamp With Time Zone
                     // INPUT : [SQLDataType]   TimestampTz + [Config] Time Zone
                     // OUTPUT: [ArrowDataType] Timestamp<TimeUnit, Some(Time Zone)>
-                    Some(self.context_provider.options().execution.time_zone.clone())
+                    self.context_provider.options().execution.time_zone.clone()
                 } else {
                     // Timestamp Without Time zone
                     None

datafusion/sqllogictest/test_files/arrow_typeof.slt

@@ -67,7 +67,7 @@ Timestamp(ns)
 query T
 SELECT arrow_typeof(now())
 ----
-Timestamp(ns, "+00:00")
+Timestamp(ns)
 
 # arrow_typeof_timestamp_date32(
 query T

datafusion/sqllogictest/test_files/dates.slt

@@ -91,7 +91,7 @@ where d3_date > now() + '5 days';
 ----
 DataFusion error: type_coercion
 caused by
-Error during planning: Cannot coerce arithmetic expression Timestamp(ns, "+00:00") + Utf8 to valid types
+Error during planning: Cannot coerce arithmetic expression Timestamp(ns) + Utf8 to valid types
 
 
 # DATE minus DATE

datafusion/sqllogictest/test_files/ddl.slt

@@ -867,7 +867,7 @@ query TTTTTT
 show columns FROM table_with_pk;
 ----
 datafusion public table_with_pk sn Int32 NO
-datafusion public table_with_pk ts Timestamp(ns, "+00:00") NO
+datafusion public table_with_pk ts Timestamp(ns) NO
 datafusion public table_with_pk currency Utf8View NO
 datafusion public table_with_pk amount Float32 YES
 

datafusion/sqllogictest/test_files/group_by.slt

@@ -5556,7 +5556,7 @@ SELECT
     arrow_cast('2024-01-01T00:00:00Z'::timestamptz, 'Timestamp(Second, Some("+08:00"))') AS ts
 GROUP BY ts, text
 ----
-foo 2024-01-01T08:00:00+08:00
+foo 2024-01-01T00:00:00+08:00
 
 # Test multi group by int + Decimal128
 statement ok

datafusion/sqllogictest/test_files/information_schema.slt

@@ -267,7 +267,7 @@ datafusion.execution.sort_spill_reservation_bytes 10485760
 datafusion.execution.spill_compression uncompressed
 datafusion.execution.split_file_groups_by_statistics false
 datafusion.execution.target_partitions 7
-datafusion.execution.time_zone +00:00
+datafusion.execution.time_zone NULL
 datafusion.execution.use_row_number_estimates_to_optimize_partitioning false
 datafusion.explain.analyze_level dev
 datafusion.explain.format indent
@@ -387,7 +387,7 @@ datafusion.execution.sort_spill_reservation_bytes 10485760 Specifies the reserve
 datafusion.execution.spill_compression uncompressed Sets the compression codec used when spilling data to disk. Since datafusion writes spill files using the Arrow IPC Stream format, only codecs supported by the Arrow IPC Stream Writer are allowed. Valid values are: uncompressed, lz4_frame, zstd. Note: lz4_frame offers faster (de)compression, but typically results in larger spill files. In contrast, zstd achieves higher compression ratios at the cost of slower (de)compression speed.
 datafusion.execution.split_file_groups_by_statistics false Attempt to eliminate sorts by packing & sorting files with non-overlapping statistics into the same file groups. Currently experimental
 datafusion.execution.target_partitions 7 Number of partitions for query execution. Increasing partitions can increase concurrency. Defaults to the number of CPU cores on the system
-datafusion.execution.time_zone +00:00 The default time zone Some functions, e.g. `EXTRACT(HOUR from SOME_TIME)`, shift the underlying datetime according to this time zone, and then extract the hour
+datafusion.execution.time_zone NULL The default time zone Some functions, e.g. `now` return timestamps in this time zone
 datafusion.execution.use_row_number_estimates_to_optimize_partitioning false Should DataFusion use row number estimates at the input to decide whether increasing parallelism is beneficial or not. By default, only exact row numbers (not estimates) are used for this decision. Setting this flag to `true` will likely produce better plans. if the source of statistics is accurate. We plan to make this the default in the future.
 datafusion.explain.analyze_level dev Verbosity level for "EXPLAIN ANALYZE". Default is "dev" "summary" shows common metrics for high-level insights. "dev" provides deep operator-level introspection for developers.
 datafusion.explain.format indent Display format of explain. Default is "indent". When set to "tree", it will print the plan in a tree-rendered format.
@@ -459,29 +459,29 @@ datafusion.execution.batch_size 8192 Default batch size while creating new batch
 query TT
 SHOW TIME ZONE
 ----
-datafusion.execution.time_zone +00:00
+datafusion.execution.time_zone NULL
 
 # show_timezone_default_utc
 # https://github.com/apache/datafusion/issues/3255
 query TT
 SHOW TIMEZONE
 ----
-datafusion.execution.time_zone +00:00
+datafusion.execution.time_zone NULL
 
 
 # show_time_zone_default_utc_verbose
 # https://github.com/apache/datafusion/issues/3255
 query TTT
 SHOW TIME ZONE VERBOSE
 ----
-datafusion.execution.time_zone +00:00 The default time zone Some functions, e.g. `EXTRACT(HOUR from SOME_TIME)`, shift the underlying datetime according to this time zone, and then extract the hour
+datafusion.execution.time_zone NULL The default time zone Some functions, e.g. `now` return timestamps in this time zone
 
 # show_timezone_default_utc
 # https://github.com/apache/datafusion/issues/3255
 query TTT
 SHOW TIMEZONE VERBOSE
 ----
-datafusion.execution.time_zone +00:00 The default time zone Some functions, e.g. `EXTRACT(HOUR from SOME_TIME)`, shift the underlying datetime according to this time zone, and then extract the hour
+datafusion.execution.time_zone NULL The default time zone Some functions, e.g. `now` return timestamps in this time zone
 
 
 # show empty verbose

datafusion/sqllogictest/test_files/metadata.slt

@@ -165,7 +165,7 @@ GROUP BY ts
 ORDER BY ts
 LIMIT 1;
 ----
-2020-09-08T13:42:29.190855123Z
+2020-09-08T13:42:29.190855123
 
 
 

datafusion/sqllogictest/test_files/parquet_filter_pushdown.slt

@@ -583,4 +583,4 @@ WHERE trace_id = '00000000000000000000000000000002' AND deployment_environment =
 ORDER BY start_timestamp, trace_id
 LIMIT 1;
 ----
-2024-10-01T00:00:00Z
+2024-10-01T00:00:00

datafusion/sqllogictest/test_files/table_functions.slt

@@ -414,7 +414,7 @@ SELECT * FROM range(TIMESTAMP '2023-01-01T00:00:00', TIMESTAMP '2023-01-03T00:00
 query P
 SELECT * FROM range(TIMESTAMPTZ '2023-02-01T00:00:00-07:00', TIMESTAMPTZ '2023-02-01T09:00:00+01:00', INTERVAL '1' HOUR);
 ----
-2023-02-01T07:00:00Z
+2023-02-01T07:00:00
 
 # Basic date range with hour interval
 query P

datafusion/sqllogictest/test_files/window.slt

@@ -942,22 +942,22 @@ CREATE TABLE table1 (
 
 statement ok
 INSERT INTO table1 (bar, foo, time) VALUES
-(200.0, 'me', '1970-01-01T00:00:00.000000010Z'),
-(1.0, 'me', '1970-01-01T00:00:00.000000030Z'),
-(1.0, 'me', '1970-01-01T00:00:00.000000040Z'),
-(2.0, 'you', '1970-01-01T00:00:00.000000020Z');
+(200.0, 'me', '1970-01-01T00:00:00.000000010'),
+(1.0, 'me', '1970-01-01T00:00:00.000000030'),
+(1.0, 'me', '1970-01-01T00:00:00.000000040'),
+(2.0, 'you', '1970-01-01T00:00:00.000000020');
 
 query TP
 SELECT foo, first_value(time ORDER BY time DESC NULLS LAST) AS time FROM table1 GROUP BY foo ORDER BY foo;
 ----
-me 1970-01-01T00:00:00.000000040Z
-you 1970-01-01T00:00:00.000000020Z
+me 1970-01-01T00:00:00.000000040
+you 1970-01-01T00:00:00.000000020
 
 query TP
 SELECT foo, last_value(time ORDER BY time DESC NULLS LAST) AS time FROM table1 GROUP BY foo ORDER BY foo;
 ----
-me 1970-01-01T00:00:00.000000010Z
-you 1970-01-01T00:00:00.000000020Z
+me 1970-01-01T00:00:00.000000010
+you 1970-01-01T00:00:00.000000020
 
 statement ok
 drop table table1;
@@ -5766,15 +5766,15 @@ CREATE TABLE table_test_distinct_count (
 
 statement ok
 INSERT INTO table_test_distinct_count (k, v, time) VALUES
-    ('a', 1, '1970-01-01T00:01:00.00Z'),
-    ('a', 1, '1970-01-01T00:02:00.00Z'),
-    ('a', 1, '1970-01-01T00:03:00.00Z'),
-    ('a', 2, '1970-01-01T00:03:00.00Z'),
-    ('a', 1, '1970-01-01T00:04:00.00Z'),
-    ('b', 3, '1970-01-01T00:01:00.00Z'),
-    ('b', 3, '1970-01-01T00:02:00.00Z'),
-    ('b', 4, '1970-01-01T00:03:00.00Z'),
-    ('b', 4, '1970-01-01T00:03:00.00Z');
+    ('a', 1, '1970-01-01T00:01:00.00'),
+    ('a', 1, '1970-01-01T00:02:00.00'),
+    ('a', 1, '1970-01-01T00:03:00.00'),
+    ('a', 2, '1970-01-01T00:03:00.00'),
+    ('a', 1, '1970-01-01T00:04:00.00'),
+    ('b', 3, '1970-01-01T00:01:00.00'),
+    ('b', 3, '1970-01-01T00:02:00.00'),
+    ('b', 4, '1970-01-01T00:03:00.00'),
+    ('b', 4, '1970-01-01T00:03:00.00');
 
 query TPII
 SELECT
@@ -5793,15 +5793,15 @@ SELECT
 FROM table_test_distinct_count
 ORDER BY k, time;
 ----
-a 1970-01-01T00:01:00Z 1 1
-a 1970-01-01T00:02:00Z 2 1
-a 1970-01-01T00:03:00Z 4 2
-a 1970-01-01T00:03:00Z 4 2
-a 1970-01-01T00:04:00Z 4 2
-b 1970-01-01T00:01:00Z 1 1
-b 1970-01-01T00:02:00Z 2 1
-b 1970-01-01T00:03:00Z 4 2
-b 1970-01-01T00:03:00Z 4 2
+a 1970-01-01T00:01:00 1 1
+a 1970-01-01T00:02:00 2 1
+a 1970-01-01T00:03:00 4 2
+a 1970-01-01T00:03:00 4 2
+a 1970-01-01T00:04:00 4 2
+b 1970-01-01T00:01:00 1 1
+b 1970-01-01T00:02:00 2 1
+b 1970-01-01T00:03:00 4 2
+b 1970-01-01T00:03:00 4 2
 
 
 query TT
@@ -5854,15 +5854,15 @@ SELECT
 FROM table_test_distinct_count
 ORDER BY k, time;
 ----
-a 1970-01-01T00:01:00Z 1 1
-a 1970-01-01T00:02:00Z 2 1
-a 1970-01-01T00:03:00Z 5 3
-a 1970-01-01T00:03:00Z 5 3
-a 1970-01-01T00:04:00Z 5 3
-b 1970-01-01T00:01:00Z 3 3
-b 1970-01-01T00:02:00Z 6 3
-b 1970-01-01T00:03:00Z 14 7
-b 1970-01-01T00:03:00Z 14 7
+a 1970-01-01T00:01:00 1 1
+a 1970-01-01T00:02:00 2 1
+a 1970-01-01T00:03:00 5 3
+a 1970-01-01T00:03:00 5 3
+a 1970-01-01T00:04:00 5 3
+b 1970-01-01T00:01:00 3 3
+b 1970-01-01T00:02:00 6 3
+b 1970-01-01T00:03:00 14 7
+b 1970-01-01T00:03:00 14 7
 
 
 

docs/source/library-user-guide/upgrading.md

@@ -182,6 +182,20 @@ let indices = projection_exprs.column_indices();
 _execution plan_ of the query. With this release, `DESCRIBE query` now outputs
 the computed _schema_ of the query, consistent with the behavior of `DESCRIBE table_name`.
 
+### `datafusion.execution.time_zone` default configuration changed
+
+The default value for `datafusion.execution.time_zone` previously was a string value of `+00:00` (GMT/Zulu time).
+This was changed to be an `Option<String>` with a default of `None`. If you want to change the timezone back
+to the previous value you can execute the sql:
+
+```sql
+SET
+TIMEZONE = '+00:00';
+```
+
+This change was made to better support using the default timezone in scalar UDF functions such as
+`now`, `current_date`, `current_time`, and `to_timestamp` among others.
+
 ## DataFusion `50.0.0`
 
 ### ListingTable automatically detects Hive Partitioned tables