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A transaction writing two branches overwrites concurrent changes to the second #4183
Description
Apache Iceberg version
0.12.0 (latest release)
Please describe the bug 🐞
Currently, Transaction._stage drops a requirement whose type is already staged, so a transaction writing two branches sends AssertRefSnapshotId for the first only, and a concurrent change to the second is overwritten. With main written first, a concurrent rollback of main is caught and retried.
import tempfile
import pyarrow as pa
from pyiceberg.catalog.sql import SqlCatalog
cat = SqlCatalog("c", uri="sqlite:///:memory:", warehouse=f"file://{tempfile.mkdtemp()}")
cat.create_namespace("ns")
row = lambda x: pa.table({"x": [x]})
t = cat.create_table("ns.t", schema=row(1).schema)
t.append(row(1))
s1 = t.current_snapshot().snapshot_id
t.append(row(2))
t.manage_snapshots().create_branch(t.current_snapshot().snapshot_id, "b").commit()
cat.load_table("ns.t").manage_snapshots().rollback_to_snapshot(s1).commit()
with t.transaction() as tx:
tx.append(row(3), branch="b")
tx.append(row(3))
print(sorted(cat.load_table("ns.t").scan().to_arrow()["x"].to_pylist()))
# [1, 2, 3], should be [1, 3]
# another writer rolled main back to [1] after t was loaded, and this commit put 2 backOn a format-version 1 table, another writer's append to main is lost the same way.
tested on pyiceberg 0.12.0 and main
Willingness to contribute
- I can contribute a fix for this bug independently
- I would be willing to contribute a fix for this bug with guidance from the Iceberg community
- I cannot contribute a fix for this bug at this time
Activity