Add in Hourly Partition Support

Author: Toruitas

.gitignore

@@ -29,3 +29,6 @@ build/
 
 # Ignore PyCharm / IntelliJ files
 .idea/
+build/
+.python-version
+docker-compose.yml

docs/source/table_partitioning.rst

@@ -292,6 +292,17 @@ Time-based partitioning
                count=12,
            ),
        ),
+
+       # 24 partitions ahead, each partition is 1 hour, for a total of 24 hours. Starting with hour 0 of current day
+       # old partitions are never deleted, `max_age` is not set
+       # partitions will be named `[table_name]_[year]_[month]_[month day number]_[hour (24h)]:00:00`.
+       PostgresPartitioningConfig(
+           model=MyPartitionedModel,
+           strategy=PostgresCurrentTimePartitioningStrategy(
+               size=PostgresTimePartitionSize(hours=1),
+               count=24,
+           ),
+       ),
    ])
 
 

psqlextra/partitioning/current_time_strategy.py

@@ -16,7 +16,8 @@ class PostgresCurrentTimePartitioningStrategy(
 
     All buckets will be equal in size and start at the start of the
     unit. With monthly partitioning, partitions start on the 1st and
-    with weekly partitioning, partitions start on monday.
+    with weekly partitioning, partitions start on monday, with hourly
+    partitioning, partitions start at 00:00.
     """
 
     def __init__(

psqlextra/partitioning/shorthands.py

@@ -16,6 +16,7 @@ def partition_by_current_time(
     months: Optional[int] = None,
     weeks: Optional[int] = None,
     days: Optional[int] = None,
+    hours: Optional[int] = None,
     max_age: Optional[relativedelta] = None,
     name_format: Optional[str] = None,
 ) -> PostgresPartitioningConfig:
@@ -43,6 +44,9 @@ def partition_by_current_time(
         days:
             The amount of days each partition should contain.
 
+        hours:
+            The amount of hours each partition should contain.
+
         max_age:
             The maximum age of a partition (calculated from the
             start of the partition).
@@ -56,7 +60,7 @@ def partition_by_current_time(
     """
 
     size = PostgresTimePartitionSize(
-        years=years, months=months, weeks=weeks, days=days
+        years=years, months=months, weeks=weeks, days=days, hours=hours
     )
 
     return PostgresPartitioningConfig(

psqlextra/partitioning/time_partition.py

@@ -20,6 +20,7 @@ class PostgresTimePartition(PostgresRangePartition):
         PostgresTimePartitionUnit.MONTHS: "%Y_%b",
         PostgresTimePartitionUnit.WEEKS: "%Y_week_%W",
         PostgresTimePartitionUnit.DAYS: "%Y_%b_%d",
+        PostgresTimePartitionUnit.HOURS: "%Y_%b_%d_%H:00:00",
     }
 
     def __init__(
@@ -31,8 +32,8 @@ def __init__(
         end_datetime = start_datetime + size.as_delta()
 
         super().__init__(
-            from_values=start_datetime.strftime("%Y-%m-%d"),
-            to_values=end_datetime.strftime("%Y-%m-%d"),
+            from_values=start_datetime.strftime("%Y-%m-%d %H:00:00"),
+            to_values=end_datetime.strftime("%Y-%m-%d %H:00:00"),
         )
 
         self.size = size

psqlextra/partitioning/time_partition_size.py

@@ -13,6 +13,7 @@ class PostgresTimePartitionUnit(enum.Enum):
     MONTHS = "months"
     WEEKS = "weeks"
     DAYS = "days"
+    HOURS = "hours"
 
 
 UNIX_EPOCH = datetime(1970, 1, 1, tzinfo=timezone.utc)
@@ -31,9 +32,10 @@ def __init__(
         months: Optional[int] = None,
         weeks: Optional[int] = None,
         days: Optional[int] = None,
+        hours: Optional[int] = None,
         anchor: datetime = UNIX_EPOCH,
     ) -> None:
-        sizes = [years, months, weeks, days]
+        sizes = [years, months, weeks, days, hours]
 
         if not any(sizes):
             raise PostgresPartitioningError("Partition cannot be 0 in size.")
@@ -56,6 +58,9 @@ def __init__(
         elif days:
             self.unit = PostgresTimePartitionUnit.DAYS
             self.value = days
+        elif hours:
+            self.unit = PostgresTimePartitionUnit.HOURS
+            self.value = hours
         else:
             raise PostgresPartitioningError(
                 "Unsupported time partitioning unit"
@@ -74,6 +79,9 @@ def as_delta(self) -> relativedelta:
         if self.unit == PostgresTimePartitionUnit.DAYS:
             return relativedelta(days=self.value)
 
+        if self.unit == PostgresTimePartitionUnit.HOURS:
+            return relativedelta(hours=self.value)
+
         raise PostgresPartitioningError(
             "Unsupported time partitioning unit: %s" % self.unit
         )
@@ -88,14 +96,21 @@ def start(self, dt: datetime) -> datetime:
         if self.unit == PostgresTimePartitionUnit.WEEKS:
             return self._ensure_datetime(dt - relativedelta(days=dt.weekday()))
 
-        diff_days = (dt - self.anchor).days
-        partition_index = diff_days // self.value
-        start = self.anchor + timedelta(days=partition_index * self.value)
-        return self._ensure_datetime(start)
+        if self.unit == PostgresTimePartitionUnit.DAYS:
+            diff_days = (dt - self.anchor).days
+            partition_index = diff_days // self.value
+            start = self.anchor + timedelta(days=partition_index * self.value)
+            return self._ensure_datetime(start)
+
+        if self.unit == PostgresTimePartitionUnit.HOURS:
+            return self._ensure_datetime(dt.replace(hour=0))
+
+        raise ValueError("Unknown unit")
 
     @staticmethod
     def _ensure_datetime(dt: Union[date, datetime]) -> datetime:
-        return datetime(year=dt.year, month=dt.month, day=dt.day)
+        hour = dt.hour if isinstance(dt, datetime) else 0
+        return datetime(year=dt.year, month=dt.month, day=dt.day, hour=hour)
 
     def __repr__(self) -> str:
         return "PostgresTimePartitionSize<%s, %s>" % (self.unit, self.value)

tests/test_partitioning_time.py

@@ -254,6 +254,56 @@ def test_partitioning_time_daily_apply():
     assert table.partitions[6].name == "2019_jun_04"
 
 
+@pytest.mark.postgres_version(lt=110000)
+def test_partitioning_time_hourly_apply():
+    """Tests whether automatically creating new partitions ahead hourly works
+    as expected."""
+
+    model = define_fake_partitioned_model(
+        {"timestamp": models.DateTimeField()}, {"key": ["timestamp"]}
+    )
+
+    schema_editor = connection.schema_editor()
+    schema_editor.create_partitioned_model(model)
+
+    # create partitions for the next 4 hours (including the current)
+    with freezegun.freeze_time("2019-1-23"):
+        manager = PostgresPartitioningManager(
+            [partition_by_current_time(model, hours=1, count=4)]
+        )
+        manager.plan().apply()
+
+    table = _get_partitioned_table(model)
+    assert len(table.partitions) == 4
+    assert table.partitions[0].name == "2019_jan_23_00:00:00"
+    assert table.partitions[1].name == "2019_jan_23_01:00:00"
+    assert table.partitions[2].name == "2019_jan_23_02:00:00"
+    assert table.partitions[3].name == "2019_jan_23_03:00:00"
+
+    # re-running it with 5, should just create one additional partition
+    with freezegun.freeze_time("2019-1-23"):
+        manager = PostgresPartitioningManager(
+            [partition_by_current_time(model, hours=1, count=5)]
+        )
+        manager.plan().apply()
+
+    table = _get_partitioned_table(model)
+    assert len(table.partitions) == 5
+    assert table.partitions[4].name == "2019_jan_23_04:00:00"
+
+    # it's june now, we want to partition two hours ahead
+    with freezegun.freeze_time("2019-06-03"):
+        manager = PostgresPartitioningManager(
+            [partition_by_current_time(model, hours=1, count=2)]
+        )
+        manager.plan().apply()
+
+    table = _get_partitioned_table(model)
+    assert len(table.partitions) == 7
+    assert table.partitions[5].name == "2019_jun_03_00:00:00"
+    assert table.partitions[6].name == "2019_jun_03_01:00:00"
+
+
 @pytest.mark.postgres_version(lt=110000)
 def test_partitioning_time_consistent_daily_apply():
     """Ensures that automatic daily partition creation is consistent and
@@ -415,11 +465,52 @@ def test_partitioning_time_daily_apply_insert():
     model.objects.create(timestamp=datetime.date(2019, 1, 10))
 
 
+@pytest.mark.postgres_version(lt=110000)
+def test_partitioning_time_hourly_apply_insert():
+    """Tests whether automatically created hourly partitions line up
+    perfectly."""
+
+    model = define_fake_partitioned_model(
+        {"timestamp": models.DateTimeField()}, {"key": ["timestamp"]}
+    )
+
+    schema_editor = connection.schema_editor()
+    schema_editor.create_partitioned_model(model)
+
+    # that's a monday
+    with freezegun.freeze_time("2019-1-07"):
+        manager = PostgresPartitioningManager(
+            [partition_by_current_time(model, hours=1, count=2)]
+        )
+        manager.plan().apply()
+
+    table = _get_partitioned_table(model)
+    assert len(table.partitions) == 2
+
+    model.objects.create(timestamp=datetime.datetime(2019, 1, 7, 0))
+    model.objects.create(timestamp=datetime.datetime(2019, 1, 7, 1))
+
+    with transaction.atomic():
+        with pytest.raises(IntegrityError):
+            model.objects.create(timestamp=datetime.datetime(2019, 1, 7, 2))
+            model.objects.create(timestamp=datetime.datetime(2019, 1, 7, 3))
+
+    with freezegun.freeze_time("2019-1-07"):
+        manager = PostgresPartitioningManager(
+            [partition_by_current_time(model, hours=1, count=4)]
+        )
+        manager.plan().apply()
+
+    model.objects.create(timestamp=datetime.datetime(2019, 1, 7, 2))
+    model.objects.create(timestamp=datetime.datetime(2019, 1, 7, 3))
+
+
 @pytest.mark.postgres_version(lt=110000)
 @pytest.mark.parametrize(
     "kwargs,partition_names",
     [
         (dict(days=2), ["2018_dec_31", "2019_jan_02"]),
+        (dict(hours=2), ["2019_jan_01_00:00:00", "2019_jan_01_02:00:00"]),
         (dict(weeks=2), ["2018_week_53", "2019_week_02"]),
         (dict(months=2), ["2019_jan", "2019_mar"]),
         (dict(years=2), ["2019", "2021"]),