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Upsert: Don't produce empty snapshots #1810

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Merged
Fokko merged 1 commit into from
Mar 19, 2025
Merged

Upsert: Don't produce empty snapshots #1810

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10 changes: 6 additions & 4 deletions pyiceberg/table/__init__.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1198,10 +1198,11 @@ def upsert(

update_row_cnt = len(rows_to_update)

# build the match predicate filter
overwrite_mask_predicate = upsert_util.create_match_filter(rows_to_update, join_cols)
if len(rows_to_update) > 0:
# build the match predicate filter
overwrite_mask_predicate = upsert_util.create_match_filter(rows_to_update, join_cols)

tx.overwrite(rows_to_update, overwrite_filter=overwrite_mask_predicate)
tx.overwrite(rows_to_update, overwrite_filter=overwrite_mask_predicate)
Comment on lines -1204 to +1205
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@kevinjqliu kevinjqliu Mar 19, 2025

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should we enforce not producing empty snapshots lower in the stack, in the write functions themselves (overwrite/append)?

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@Fokko Fokko Mar 19, 2025

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Yes, that's a great suggestion. I was also looking into that, but there are two caveats:

  • Before computing all the manifests, we don't know if they are empty. The delete manifests are lazily computed, so making sure that we short-circuit earlier in the process, makes sure that we don't do all the work.
  • There is also a behavioral aspect around it, for example, when you do tbl.append(df) where df is empty, or tbl.delete('x = 10'), you may still want to produce a snapshot to indicate that something happened. My opinion is that it should result in a no-op, but Java creates a snapshot:

image

I believe @sungwy and I had a similar discussion.


if when_not_matched_insert_all:
expr_match = upsert_util.create_match_filter(matched_iceberg_table, join_cols)
Expand All @@ -1211,7 +1212,8 @@ def upsert(

insert_row_cnt = len(rows_to_insert)

tx.append(rows_to_insert)
if insert_row_cnt > 0:
tx.append(rows_to_insert)

return UpsertResult(rows_updated=update_row_cnt, rows_inserted=insert_row_cnt)

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13 changes: 13 additions & 0 deletions tests/table/test_upsert.py
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Original file line number Diff line number Diff line change
Expand Up @@ -28,6 +28,7 @@
from pyiceberg.io.pyarrow import schema_to_pyarrow
from pyiceberg.schema import Schema
from pyiceberg.table import UpsertResult
from pyiceberg.table.snapshots import Operation
from pyiceberg.table.upsert_util import create_match_filter
from pyiceberg.types import IntegerType, NestedField, StringType
from tests.catalog.test_base import InMemoryCatalog, Table
Expand Down Expand Up @@ -368,9 +369,21 @@ def test_upsert_with_identifier_fields(catalog: Catalog) -> None:
)
upd = tbl.upsert(df)

expected_operations = [Operation.APPEND, Operation.OVERWRITE, Operation.APPEND, Operation.APPEND]

assert upd.rows_updated == 1
assert upd.rows_inserted == 1

assert [snap.summary.operation for snap in tbl.snapshots() if snap.summary is not None] == expected_operations

# This should be a no-op
upd = tbl.upsert(df)

assert upd.rows_updated == 0
assert upd.rows_inserted == 0

assert [snap.summary.operation for snap in tbl.snapshots() if snap.summary is not None] == expected_operations


def test_upsert_into_empty_table(catalog: Catalog) -> None:
identifier = "default.test_upsert_into_empty_table"
Expand Down