Fokko commented on code in PR #4717:
URL: https://github.com/apache/iceberg/pull/4717#discussion_r894871233
##########
python/src/iceberg/table/partitioning.py:
##########
@@ -29,38 +36,81 @@ class PartitionField:
name(str): The name of this partition field
"""
- def __init__(self, source_id: int, field_id: int, transform: Transform,
name: str):
- self._source_id = source_id
- self._field_id = field_id
- self._transform = transform
- self._name = name
+ source_id: int
+ field_id: int
+ transform: Transform
+ name: str
+
+ def __str__(self):
+ return f"{self.field_id}: {self.name}:
{self.transform}({self.source_id})"
+
- @property
- def source_id(self) -> int:
- return self._source_id
+@dataclass(eq=False, frozen=True)
+class PartitionSpec:
+ """
+ PartitionSpec captures the transformation from table data to partition
values
- @property
- def field_id(self) -> int:
- return self._field_id
+ Attributes:
+ schema(Schema): the schema of data table
+ spec_id(int): any change to PartitionSpec will produce a new specId
+ fields(List[PartitionField): list of partition fields to produce
partition values
+ last_assigned_field_id(int): auto-increment partition field id
starting from PARTITION_DATA_ID_START
+ """
- @property
- def name(self) -> str:
- return self._name
+ schema: Schema
+ spec_id: int
+ fields: Tuple[PartitionField, ...]
+ last_assigned_field_id: int
+ source_id_to_fields_map: Dict[int, List[PartitionField]] =
field(init=False, repr=False)
- @property
- def transform(self) -> Transform:
- return self._transform
+ def __post_init__(self):
+ source_id_to_fields_map = dict()
+ for partition_field in self.fields:
+ source_column =
self.schema.find_column_name(partition_field.source_id)
+ if not source_column:
+ raise ValueError(f"Cannot find source column:
{partition_field.source_id}")
+ existing = source_id_to_fields_map.get(partition_field.source_id,
[])
+ existing.append(partition_field)
+ source_id_to_fields_map[partition_field.source_id] = existing
+ object.__setattr__(self, "source_id_to_fields_map",
source_id_to_fields_map)
def __eq__(self, other):
- return (
- self.field_id == other.field_id
- and self.source_id == other.source_id
- and self.name == other.name
- and self.transform == other.transform
- )
+ """
+ Produce a boolean to return True if two objects are considered equal
+
+ Note:
+ Equality of PartitionSpec is determined by spec_id and partition
fields only
+ """
+ if not isinstance(other, PartitionSpec):
+ return False
+ return self.spec_id == other.spec_id and self.fields == other.fields
def __str__(self):
- return f"{self.field_id}: {self.name}:
{self.transform}({self.source_id})"
+ """
+ Produce a human-readable string representation of PartitionSpec
- def __repr__(self):
- return f"PartitionField(field_id={self.field_id}, name={self.name},
transform={repr(self.transform)}, source_id={self.source_id})"
+ Note:
+ Only include list of partition fields in the PartitionSpec's
string representation
+ """
+ result_str = "["
+ if self.fields:
+ result_str += "\n " + "\n ".join([str(field) for field in
self.fields]) + "\n"
+ result_str += "]"
+ return result_str
+
+ def is_unpartitioned(self) -> bool:
+ return len(self.fields) < 1
+
+ def fields_by_source_id(self, field_id: int) -> List[PartitionField]:
+ return self.source_id_to_fields_map[field_id]
+
+ def compatible_with(self, other: "PartitionSpec") -> bool:
Review Comment:
We should also assert the number of fields. The following test is passing:
```python
def test_partition_compatible_with(table_schema_simple: Schema):
bucket_transform = bucket(IntegerType(), 4)
field1 = PartitionField(3, 100, bucket_transform, "id")
field2 = PartitionField(3, 102, bucket_transform, "id")
lhs = PartitionSpec(table_schema_simple, 0, (field1,), 1001)
rhs = PartitionSpec(table_schema_simple, 0, (field1, field2), 1001)
assert lhs.compatible_with(rhs)
```
<img width="1624" alt="image"
src="https://user-images.githubusercontent.com/1134248/173146156-8e4f9459-92f7-4cc2-ada9-a1a11582b402.png";>
We also do this on the Java side:
https://github.com/apache/iceberg/blob/master/api/src/main/java/org/apache/iceberg/PartitionSpec.java#L211
The Python zip will only zip the number of fields that are in the shortest
list.
##########
python/src/iceberg/table/partitioning.py:
##########
@@ -29,38 +36,81 @@ class PartitionField:
name(str): The name of this partition field
"""
- def __init__(self, source_id: int, field_id: int, transform: Transform,
name: str):
- self._source_id = source_id
- self._field_id = field_id
- self._transform = transform
- self._name = name
+ source_id: int
+ field_id: int
+ transform: Transform
+ name: str
+
+ def __str__(self):
+ return f"{self.field_id}: {self.name}:
{self.transform}({self.source_id})"
+
- @property
- def source_id(self) -> int:
- return self._source_id
+@dataclass(eq=False, frozen=True)
+class PartitionSpec:
+ """
+ PartitionSpec captures the transformation from table data to partition
values
- @property
- def field_id(self) -> int:
- return self._field_id
+ Attributes:
+ schema(Schema): the schema of data table
+ spec_id(int): any change to PartitionSpec will produce a new specId
+ fields(List[PartitionField): list of partition fields to produce
partition values
+ last_assigned_field_id(int): auto-increment partition field id
starting from PARTITION_DATA_ID_START
+ """
- @property
- def name(self) -> str:
- return self._name
+ schema: Schema
+ spec_id: int
+ fields: Tuple[PartitionField, ...]
+ last_assigned_field_id: int
+ source_id_to_fields_map: Dict[int, List[PartitionField]] =
field(init=False, repr=False)
- @property
- def transform(self) -> Transform:
- return self._transform
+ def __post_init__(self):
+ source_id_to_fields_map = dict()
+ for partition_field in self.fields:
+ source_column =
self.schema.find_column_name(partition_field.source_id)
+ if not source_column:
+ raise ValueError(f"Cannot find source column:
{partition_field.source_id}")
+ existing = source_id_to_fields_map.get(partition_field.source_id,
[])
+ existing.append(partition_field)
+ source_id_to_fields_map[partition_field.source_id] = existing
+ object.__setattr__(self, "source_id_to_fields_map",
source_id_to_fields_map)
def __eq__(self, other):
- return (
- self.field_id == other.field_id
- and self.source_id == other.source_id
- and self.name == other.name
- and self.transform == other.transform
- )
+ """
+ Produce a boolean to return True if two objects are considered equal
+
+ Note:
+ Equality of PartitionSpec is determined by spec_id and partition
fields only
+ """
+ if not isinstance(other, PartitionSpec):
+ return False
+ return self.spec_id == other.spec_id and self.fields == other.fields
def __str__(self):
- return f"{self.field_id}: {self.name}:
{self.transform}({self.source_id})"
+ """
+ Produce a human-readable string representation of PartitionSpec
- def __repr__(self):
- return f"PartitionField(field_id={self.field_id}, name={self.name},
transform={repr(self.transform)}, source_id={self.source_id})"
+ Note:
+ Only include list of partition fields in the PartitionSpec's
string representation
+ """
+ result_str = "["
+ if self.fields:
+ result_str += "\n " + "\n ".join([str(field) for field in
self.fields]) + "\n"
+ result_str += "]"
+ return result_str
+
+ def is_unpartitioned(self) -> bool:
+ return len(self.fields) < 1
Review Comment:
supernit: We could shorten this to:
```suggestion
return not self.fields
```
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![https://user-images.githubusercontent.com/1134248/173146156-8e4f9459-92f7-4cc2-ada9-a1a11582b402.png"](https://user-images.githubusercontent.com/1134248/173146156-8e4f9459-92f7-4cc2-ada9-a1a11582b402.png"){kind=link}