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fix: Break event timestamp ties by created timestamp in the Dask offline store - #6952

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shuchu merged 2 commits into
feast-dev:masterfrom
LuisFigueroaG:fix/dask-created-timestamp-tiebreak
Nov 10, 2026
Merged

shuchu merged 2 commits into
feast-dev:masterfrom
LuisFigueroaG:fix/dask-created-timestamp-tiebreak

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What this PR does / why we need it:

When two rows share an event timestamp, Feast is supposed to keep the one with the latest created_timestamp_column. The Dask offline store did this with two consecutive sorts, first by the created timestamp and then by the event timestamp, and relied on the second sort preserving the order of the first:

df_to_join = df_to_join.sort_values(by=created_timestamp_column, na_position="first")
df_to_join = df_to_join.sort_values(by=timestamp_field, na_position="first")

Dask's sort_values (and pandas' default quicksort) is not stable, so for tied event timestamps the older row can end up last and win drop_duplicates(keep="last"). With 300 entities, each having two rows with the same event timestamp, 291 came back with the older row. A single partition with 20 entities already returned 12 wrong rows. This affects get_historical_features (_drop_duplicates) and pull_latest_from_table_or_query (evaluate_offline_job).

This sorts once by [timestamp_field, created_timestamp_column] in both places, including the ZeroDivisionError fallbacks. Multi-column sort_values is supported by dask since well before the dask>=2024.2.1 minimum.

Which issue(s) this PR fixes:

No existing issue.

Checks

  • I've made sure the tests are passing.
  • My commits are signed off (git commit -s)
  • My PR title follows conventional commits format

Testing Strategy

  • Unit tests
  • Integration tests
  • Manual tests
  • Testing is not required for this change

Added test_dask_created_timestamp_tiebreak.py, covering get_historical_features and pull_latest_from_table_or_query with 100 entities across 4 partitions. Both tests failed in 5 out of 5 runs on master and pass with this change. ruff format --check, ruff check and mypy pass on the changed files, and sdk/python/tests/unit/infra/offline_stores/ passes (291 passed).

…ine store

The Dask offline store sorted by created_timestamp_column and then by
timestamp_field in a second pass, relying on that second sort to keep
the created timestamp order for rows sharing an event timestamp.
sort_values is not stable, so with enough rows the older row could end
up last and win the keep="last" deduplication, both in historical
retrieval and in pull_latest_from_table_or_query.

Sort once by [timestamp_field, created_timestamp_column] instead.

Signed-off-by: LuisFigueroaG <[email protected]>
@LuisFigueroaG
LuisFigueroaG requested a review from a team as a code owner October 6, 2026 01:27
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❌ Patch coverage is 90.90909% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 49.05%. Comparing base (acadb17) to head (a6f2696).
⚠️ Report is 8 commits behind head on master.

Files with missing lines Patch % Lines
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@@           Coverage Diff           @@
##           master    #6952   +/-   ##
=======================================
  Coverage   49.04%   49.05%           
=======================================
  Files         433      433           
  Lines       54308    54304    -4     
  Branches     7910     7908    -2     
=======================================
+ Hits        26637    26640    +3     
+ Misses      25790    25785    -5     
+ Partials     1881     1879    -2     
Flag Coverage Δ
go-feature-server 30.58% <ø> (ø)
python-unit 50.45% <90.90%> (+<0.01%) ⬆️
Files with missing lines Coverage Δ
sdk/python/feast/infra/offline_stores/dask.py 56.23% <90.90%> (+0.80%) ⬆️

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lgtm

@shuchu
shuchu merged commit eb93b08 into feast-dev:master Nov 10, 2026
13 of 20 checks passed
franciscojavierarceo pushed a commit that referenced this pull request Nov 10, 2026
# [0.68.0](v0.67.0...v0.68.0) (2026-11-10)

### Bug Fixes

* add watch verb on clusterroles and clusterrolebindings for feast-operator ([#7062](#7062)) ([b6bdda4](b6bdda4))
* Apply on demand feature views in SparkRetrievalJob.to_spark_df() ([#6993](#6993)) ([f416309](f416309))
* Break event timestamp ties by created timestamp in Milvus write batches ([#7084](#7084)) ([bbaca76](bbaca76))
* Break event timestamp ties by created timestamp in the Dask offline store ([#6952](#6952)) ([eb93b08](eb93b08))
* Build the Go feature server image in two stages ([1e5e90c](1e5e90c)), closes [#7060](#7060)
* Fall back to the serialized body when UDF source misses globals ([#6816](#6816)) ([f61079f](f61079f))
* Install patched libbrotli1 to address DSA-6582-1 ([#7096](#7096)) ([d458393](d458393))
* Keep description, tags and nested types of ODFV schema fields ([8ef6e75](8ef6e75))
* Keep entity columns out of StreamFeatureView proto features ([#7033](#7033)) ([d520584](d520584))
* Keep the metrics server running when a Gunicorn worker exits ([#7012](#7012)) ([68c5d54](68c5d54)), closes [#7011](#7011)
* Key registry proto caches on the proto, not its id() ([#7085](#7085)) ([147adad](147adad))
* Log ODFV materialization skips instead of printing them ([#7117](#7117)) ([8fdcee7](8fdcee7))
* Pin build dependencies of source builds to the CI lock ([#7104](#7104)) ([dec2f24](dec2f24))
* Populate spec.project in registry REST feature view responses (#… ([#7037](#7037)) ([e304a84](e304a84))
* Preserve colliding source timestamps in Dask retrieval ([#7071](#7071)) ([1396c88](1396c88))
* Preserve Dask historical requests without eligible features ([#7000](#7000)) ([fff09f7](fff09f7))
* Read None elements of UUID and Decimal lists as None ([#7039](#7039)) ([03f30fe](03f30fe))
* Retire the support of Python3.10 ([#7101](#7101)) ([a56766e](a56766e)), closes [#7104](#7104) [#7089](#7089) [#7106](#7106) [#7105](#7105)
* Serialize UUID and TimeUuid entity keys ([#7032](#7032)) ([0c845a1](0c845a1))
* Stop the Ray engine from hiding materialization errors ([#7026](#7026)) ([7903e2e](7903e2e)), closes [#7024](#7024)
* **ui:** stop treating the monitoring baseline as the latest window ([#7056](#7056)) ([0f01802](0f01802)), closes [#7054](#7054)
* Use date-only bounds for partition filters built from string timestamps ([#7116](#7116)) ([b1f2168](b1f2168))
* Validate entity column types in feast dbt import ([#7067](#7067)) ([abca80c](abca80c)), closes [#5876](#5876)
* Warm up the whole DynamoDB connection pool ([#6985](#6985)) ([8ce548c](8ce548c))

### Features

* Add --gc-freeze option to feast serve ([#7089](#7089)) ([aad0c15](aad0c15))
* Add native complex types and scalar index tags to the Milvus online store ([#7120](#7120)) ([f7068d6](f7068d6))
* Add num_partitions and partition_key_isolation to the Milvus online store ([#7083](#7083)) ([68de84e](68de84e)), closes [#6940](#6940)
* Add Pinecone online store integration ([#6585](#6585)) ([7a84f2a](7a84f2a))
* Add PolarisSource and PolarisProvider for Apache Polaris ([#7006](#7006)) ([386759c](386759c))
* Add row deletion to the Milvus online store ([#7082](#7082)) ([d3e2041](d3e2041))
* Add upstream FeatureView lineage support for PushSource ([#6853](#6853)) ([c9b9d72](c9b9d72))
* Optional nameless pre-computed vectors with a schema fingerprint ([#7077](#7077)) ([9420fac](9420fac))

### Performance Improvements

* Scan Lance sources lazily in the DuckDB offline store ([1299e4e](1299e4e))
shuchu added a commit to shuchu/feast that referenced this pull request Nov 11, 2026
…ine store (feast-dev#6952)

The Dask offline store sorted by created_timestamp_column and then by
timestamp_field in a second pass, relying on that second sort to keep
the created timestamp order for rows sharing an event timestamp.
sort_values is not stable, so with enough rows the older row could end
up last and win the keep="last" deduplication, both in historical
retrieval and in pull_latest_from_table_or_query.

Sort once by [timestamp_field, created_timestamp_column] instead.

Signed-off-by: LuisFigueroaG <[email protected]>
Co-authored-by: Shuchu Han <[email protected]>
Signed-off-by: Shuchu Han <[email protected]>
shuchu pushed a commit to shuchu/feast that referenced this pull request Nov 11, 2026
# [0.68.0](feast-dev/feast@v0.67.0...v0.68.0) (2026-11-10)

### Bug Fixes

* add watch verb on clusterroles and clusterrolebindings for feast-operator ([feast-dev#7062](feast-dev#7062)) ([b6bdda4](feast-dev@b6bdda4))
* Apply on demand feature views in SparkRetrievalJob.to_spark_df() ([feast-dev#6993](feast-dev#6993)) ([f416309](feast-dev@f416309))
* Break event timestamp ties by created timestamp in Milvus write batches ([feast-dev#7084](feast-dev#7084)) ([bbaca76](feast-dev@bbaca76))
* Break event timestamp ties by created timestamp in the Dask offline store ([feast-dev#6952](feast-dev#6952)) ([eb93b08](feast-dev@eb93b08))
* Build the Go feature server image in two stages ([1e5e90c](feast-dev@1e5e90c)), closes [feast-dev#7060](feast-dev#7060)
* Fall back to the serialized body when UDF source misses globals ([feast-dev#6816](feast-dev#6816)) ([f61079f](feast-dev@f61079f))
* Install patched libbrotli1 to address DSA-6582-1 ([feast-dev#7096](feast-dev#7096)) ([d458393](feast-dev@d458393))
* Keep description, tags and nested types of ODFV schema fields ([8ef6e75](feast-dev@8ef6e75))
* Keep entity columns out of StreamFeatureView proto features ([feast-dev#7033](feast-dev#7033)) ([d520584](feast-dev@d520584))
* Keep the metrics server running when a Gunicorn worker exits ([feast-dev#7012](feast-dev#7012)) ([68c5d54](feast-dev@68c5d54)), closes [feast-dev#7011](feast-dev#7011)
* Key registry proto caches on the proto, not its id() ([feast-dev#7085](feast-dev#7085)) ([147adad](feast-dev@147adad))
* Log ODFV materialization skips instead of printing them ([feast-dev#7117](feast-dev#7117)) ([8fdcee7](feast-dev@8fdcee7))
* Pin build dependencies of source builds to the CI lock ([feast-dev#7104](feast-dev#7104)) ([dec2f24](feast-dev@dec2f24))
* Populate spec.project in registry REST feature view responses (#… ([feast-dev#7037](feast-dev#7037)) ([e304a84](feast-dev@e304a84))
* Preserve colliding source timestamps in Dask retrieval ([feast-dev#7071](feast-dev#7071)) ([1396c88](feast-dev@1396c88))
* Preserve Dask historical requests without eligible features ([feast-dev#7000](feast-dev#7000)) ([fff09f7](feast-dev@fff09f7))
* Read None elements of UUID and Decimal lists as None ([feast-dev#7039](feast-dev#7039)) ([03f30fe](feast-dev@03f30fe))
* Retire the support of Python3.10 ([feast-dev#7101](feast-dev#7101)) ([a56766e](feast-dev@a56766e)), closes [feast-dev#7104](feast-dev#7104) [feast-dev#7089](feast-dev#7089) [feast-dev#7106](feast-dev#7106) [feast-dev#7105](feast-dev#7105)
* Serialize UUID and TimeUuid entity keys ([feast-dev#7032](feast-dev#7032)) ([0c845a1](feast-dev@0c845a1))
* Stop the Ray engine from hiding materialization errors ([feast-dev#7026](feast-dev#7026)) ([7903e2e](feast-dev@7903e2e)), closes [feast-dev#7024](feast-dev#7024)
* **ui:** stop treating the monitoring baseline as the latest window ([feast-dev#7056](feast-dev#7056)) ([0f01802](feast-dev@0f01802)), closes [feast-dev#7054](feast-dev#7054)
* Use date-only bounds for partition filters built from string timestamps ([feast-dev#7116](feast-dev#7116)) ([b1f2168](feast-dev@b1f2168))
* Validate entity column types in feast dbt import ([feast-dev#7067](feast-dev#7067)) ([abca80c](feast-dev@abca80c)), closes [feast-dev#5876](feast-dev#5876)
* Warm up the whole DynamoDB connection pool ([feast-dev#6985](feast-dev#6985)) ([8ce548c](feast-dev@8ce548c))

### Features

* Add --gc-freeze option to feast serve ([feast-dev#7089](feast-dev#7089)) ([aad0c15](feast-dev@aad0c15))
* Add native complex types and scalar index tags to the Milvus online store ([feast-dev#7120](feast-dev#7120)) ([f7068d6](feast-dev@f7068d6))
* Add num_partitions and partition_key_isolation to the Milvus online store ([feast-dev#7083](feast-dev#7083)) ([68de84e](feast-dev@68de84e)), closes [feast-dev#6940](feast-dev#6940)
* Add Pinecone online store integration ([feast-dev#6585](feast-dev#6585)) ([7a84f2a](feast-dev@7a84f2a))
* Add PolarisSource and PolarisProvider for Apache Polaris ([feast-dev#7006](feast-dev#7006)) ([386759c](feast-dev@386759c))
* Add row deletion to the Milvus online store ([feast-dev#7082](feast-dev#7082)) ([d3e2041](feast-dev@d3e2041))
* Add upstream FeatureView lineage support for PushSource ([feast-dev#6853](feast-dev#6853)) ([c9b9d72](feast-dev@c9b9d72))
* Optional nameless pre-computed vectors with a schema fingerprint ([feast-dev#7077](feast-dev#7077)) ([9420fac](feast-dev@9420fac))

### Performance Improvements

* Scan Lance sources lazily in the DuckDB offline store ([1299e4e](feast-dev@1299e4e))

Signed-off-by: Shuchu Han <[email protected]>
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