smaheshwar-pltr commented on code in PR #3364:
URL: https://github.com/apache/iceberg-python/pull/3364#discussion_r3260051287
##########
pyiceberg/table/__init__.py:
##########
@@ -2103,116 +2189,346 @@ def plan_files(self) -> Iterable[FileScanTask]:
return self._plan_files_server_side()
return self._plan_files_local()
- def to_arrow(self) -> pa.Table:
- """Read an Arrow table eagerly from this DataScan.
+ def count(self) -> int:
+ from pyiceberg.io.pyarrow import ArrowScan
- All rows will be loaded into memory at once.
+ # Usage: Calculates the total number of records in a Scan that haven't
had positional deletes.
+ res = 0
+ # every task is a FileScanTask
+ tasks = self.plan_files()
- Returns:
- pa.Table: Materialized Arrow Table from the Iceberg table's
DataScan
- """
- from pyiceberg.io.pyarrow import ArrowScan
+ for task in tasks:
+ # task.residual is a Boolean Expression if the filter condition is
fully satisfied by the
+ # partition value and task.delete_files represents that positional
delete haven't been merged yet
+ # hence those files have to read as a pyarrow table applying the
filter and deletes
+ if task.residual == AlwaysTrue() and len(task.delete_files) == 0:
+ # Every File has a metadata stat that stores the file record
count
+ res += task.file.record_count
+ else:
+ arrow_scan = ArrowScan(
+ table_metadata=self.table_metadata,
+ io=self.io,
+ projected_schema=self.projection(),
+ row_filter=self.row_filter,
+ case_sensitive=self.case_sensitive,
+ )
+ tbl = arrow_scan.to_table([task])
+ res += len(tbl)
+ return res
- return ArrowScan(
- self.table_metadata, self.io, self.projection(), self.row_filter,
self.case_sensitive, self.limit
- ).to_table(self.plan_files())
- def to_arrow_batch_reader(self) -> pa.RecordBatchReader:
- """Return an Arrow RecordBatchReader from this DataScan.
+IAS = TypeVar("IAS", bound="IncrementalAppendScan", covariant=True)
- For large results, using a RecordBatchReader requires less memory than
- loading an Arrow Table for the same DataScan, because a RecordBatch
- is read one at a time.
- Returns:
- pa.RecordBatchReader: Arrow RecordBatchReader from the Iceberg
table's DataScan
- which can be used to read a stream of record batches one by
one.
- """
- import pyarrow as pa
+class IncrementalAppendScan(BaseScan):
+ """An incremental scan of a table's data that accumulates appended data
between two snapshots.
- from pyiceberg.io.pyarrow import ArrowScan, schema_to_pyarrow
+ Args:
+ row_filter:
+ A string or BooleanExpression that describes the
+ desired rows
+ selected_fields:
+ A tuple of strings representing the column names
+ to return in the output dataframe.
+ case_sensitive:
+ If True column matching is case sensitive
+ options:
+ Additional Table properties as a dictionary of
+ string key value pairs to use for this scan.
+ limit:
+ An integer representing the number of rows to
+ return in the scan result. If None, fetches all
+ matching rows.
+ from_snapshot_id_exclusive:
+ Optional ID of the "from" snapshot, to start the incremental scan
from, exclusively. When the scan is
+ ultimately planned, this must not be None. The snapshot does not
need to be present in the table metadata
+ (it may have been expired), as long as it is the parent of some
ancestor of the "to" snapshot.
+ to_snapshot_id_inclusive:
+ Optional ID of the "to" snapshot, to end the incremental scan at,
inclusively.
+ Omitting it will default to the table's current snapshot.
+ """
- target_schema = schema_to_pyarrow(self.projection())
- batches = ArrowScan(
- self.table_metadata, self.io, self.projection(), self.row_filter,
self.case_sensitive, self.limit
- ).to_record_batches(self.plan_files())
+ from_snapshot_id_exclusive: int | None
+ to_snapshot_id_inclusive: int | None
- return pa.RecordBatchReader.from_batches(
- target_schema,
- batches,
- ).cast(target_schema)
+ def __init__(
+ self,
+ table_metadata: TableMetadata,
+ io: FileIO,
+ row_filter: str | BooleanExpression = ALWAYS_TRUE,
+ selected_fields: tuple[str, ...] = ("*",),
+ case_sensitive: bool = True,
+ options: Properties = EMPTY_DICT,
+ limit: int | None = None,
+ from_snapshot_id_exclusive: int | None = None,
+ to_snapshot_id_inclusive: int | None = None,
+ ):
+ super().__init__(
+ table_metadata=table_metadata,
+ io=io,
+ row_filter=row_filter,
+ selected_fields=selected_fields,
+ case_sensitive=case_sensitive,
+ options=options,
+ limit=limit,
+ )
+ self.from_snapshot_id_exclusive = from_snapshot_id_exclusive
+ self.to_snapshot_id_inclusive = to_snapshot_id_inclusive
- def to_pandas(self, **kwargs: Any) -> pd.DataFrame:
- """Read a Pandas DataFrame eagerly from this Iceberg table.
+ def from_snapshot_exclusive(self: IAS, from_snapshot_id_exclusive: int |
None) -> IAS:
+ """Instructs this scan to look for changes starting from a particular
snapshot (exclusive).
+
+ Args:
+ from_snapshot_id_exclusive: the start snapshot ID (exclusive)
Returns:
- pd.DataFrame: Materialized Pandas Dataframe from the Iceberg table
+ this for method chaining
"""
- return self.to_arrow().to_pandas(**kwargs)
+ return
self.update(from_snapshot_id_exclusive=from_snapshot_id_exclusive)
- def to_duckdb(self, table_name: str, connection: DuckDBPyConnection | None
= None) -> DuckDBPyConnection:
- """Shorthand for loading the Iceberg Table in DuckDB.
+ def to_snapshot_inclusive(self: IAS, to_snapshot_id_inclusive: int | None)
-> IAS:
+ """Instructs this scan to look for changes up to a particular snapshot
(inclusive).
+
+ Args:
+ to_snapshot_id_inclusive: the end snapshot ID (inclusive)
Returns:
- DuckDBPyConnection: In memory DuckDB connection with the Iceberg
table.
+ this for method chaining
"""
- import duckdb
+ return self.update(to_snapshot_id_inclusive=to_snapshot_id_inclusive)
- con = connection or duckdb.connect(database=":memory:")
- con.register(table_name, self.to_arrow())
+ def projection(self) -> Schema:
+ current_schema = self.table_metadata.schema()
+ if "*" in self.selected_fields:
+ return current_schema
+ return current_schema.select(*self.selected_fields,
case_sensitive=self.case_sensitive)
- return con
+ def plan_files(self) -> Iterable[FileScanTask]:
+ """Plans the relevant files added between the specified snapshots."""
+ from_snapshot_id, to_snapshot_id =
self._validate_and_resolve_snapshots()
+
+ append_snapshots = [
+ snapshot
+ for snapshot in ancestors_between_ids(
+ from_snapshot_id_exclusive=from_snapshot_id,
+ to_snapshot_id_inclusive=to_snapshot_id,
+ table_metadata=self.table_metadata,
+ )
+ if snapshot.summary is not None and snapshot.summary.operation ==
Operation.APPEND
+ ]
+ if len(append_snapshots) == 0:
+ return iter([])
- def to_ray(self) -> ray.data.dataset.Dataset:
- """Read a Ray Dataset eagerly from this Iceberg table.
+ append_snapshot_ids = {snapshot.snapshot_id for snapshot in
append_snapshots}
- Returns:
- ray.data.dataset.Dataset: Materialized Ray Dataset from the
Iceberg table
- """
- import ray
+ manifests = list(
+ {
+ manifest_file
+ for snapshot in append_snapshots
+ for manifest_file in snapshot.manifests(self.io)
+ if manifest_file.content == ManifestContent.DATA and
manifest_file.added_snapshot_id in append_snapshot_ids
+ }
+ )
- return ray.data.from_arrow(self.to_arrow())
+ return ManifestGroupPlanner(
+ table_metadata=self.table_metadata,
+ io=self.io,
+ row_filter=self.row_filter,
+ case_sensitive=self.case_sensitive,
+ options=self.options,
+ ).plan_files(
+ manifests=manifests,
+ manifest_entry_filter=lambda manifest_entry:
manifest_entry.snapshot_id in append_snapshot_ids
+ and manifest_entry.status == ManifestEntryStatus.ADDED,
+ )
- def to_polars(self) -> pl.DataFrame:
- """Read a Polars DataFrame from this Iceberg table.
+ def _validate_and_resolve_snapshots(self) -> tuple[int, int]:
+ if self.from_snapshot_id_exclusive is None:
+ raise ValueError("Start snapshot is not set, please set
from_snapshot_id_exclusive")
- Returns:
- pl.DataFrame: Materialized Polars Dataframe from the Iceberg table
+ if self.to_snapshot_id_inclusive is None:
+ current_snapshot = self.table_metadata.current_snapshot()
+ if current_snapshot is None:
+ raise ValueError("End snapshot is not set and table has no
current snapshot")
+ to_snapshot_id = current_snapshot.snapshot_id
+ else:
+ if
self.table_metadata.snapshot_by_id(self.to_snapshot_id_inclusive) is None:
+ raise ValueError(f"End snapshot not found in table metadata:
{self.to_snapshot_id_inclusive}")
+ to_snapshot_id = self.to_snapshot_id_inclusive
+
+ # The start snapshot is exclusive, so it does not need to be present
in the table metadata
+ # (it may have been expired). It is valid as long as it is the parent
of some ancestor of
+ # the end snapshot.
+ if not is_parent_ancestor_of(to_snapshot_id,
self.from_snapshot_id_exclusive, self.table_metadata):
+ raise ValueError(
+ f"Starting snapshot (exclusive)
{self.from_snapshot_id_exclusive} is not a parent "
+ f"ancestor of end snapshot {to_snapshot_id}"
+ )
+
+ return self.from_snapshot_id_exclusive, to_snapshot_id
+
+
+class ManifestGroupPlanner:
Review Comment:
Motivated by Java's
[`ManifestGroup`](https://github.com/apache/iceberg/blob/2f6606a247e2b16be46ca6c02fc4cfc2e17691e6/core/src/main/java/org/apache/iceberg/ManifestGroup.java#L49)
— both `DataScan` and `IncrementalAppendScan` need to plan file scan tasks
from a set of manifests with optional filtering, and this is the natural shape
for that ([prior
thinking](https://github.com/apache/iceberg-python/pull/2031#discussion_r2102779860)).
All the `_build_*` helpers and `_check_sequence_number` are **moved** from
`DataScan`, not new.
##########
pyiceberg/table/snapshots.py:
##########
@@ -431,6 +431,42 @@ def ancestors_between(from_snapshot: Snapshot | None,
to_snapshot: Snapshot, tab
yield from ancestors_of(to_snapshot, table_metadata)
+def ancestors_between_ids(
Review Comment:
Mirrors Java's
[`SnapshotUtil.ancestorsBetween`](https://github.com/apache/iceberg/blob/2f6606a247e2b16be46ca6c02fc4cfc2e17691e6/core/src/main/java/org/apache/iceberg/util/SnapshotUtil.java#L216-L229).
Differs from the existing `ancestors_between` (snapshot-based,
inclusive-inclusive) above by taking IDs and being exclusive-inclusive, to
match the incremental-scan validation pattern. Raises if
`to_snapshot_id_inclusive` is missing from metadata, mirroring Java.
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