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feat: enable native Iceberg reader by default #3819

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438e985
feat: enable native Iceberg reader by default
andygrove Mar 27, 2026
4813f7a
Merge branch 'main' into enable-iceberg-native-default
mbutrovich Mar 30, 2026
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4 changes: 2 additions & 2 deletions benchmarks/tpc/README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -179,8 +179,8 @@ sudo ./drop-caches.sh
python3 run.py --engine comet-iceberg --benchmark tpch
```

The benchmark uses `spark.comet.scan.icebergNative.enabled=true` to enable Comet's native iceberg-rust
integration. Verify native scanning is active by checking for `CometIcebergNativeScanExec` in the
The benchmark uses Comet's native iceberg-rust integration, which is enabled by default.
Verify native scanning is active by checking for `CometIcebergNativeScanExec` in the
physical plan output.

### create-iceberg-tables.py options
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2 changes: 1 addition & 1 deletion common/src/main/scala/org/apache/comet/CometConf.scala
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Expand Up @@ -140,7 +140,7 @@ object CometConf extends ShimCometConf {
"Iceberg tables are read directly through native execution, bypassing Spark's " +
"DataSource V2 API for better performance.")
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@martin-g martin-g Apr 1, 2026

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https://datafusion.apache.org/comet/user-guide/latest/iceberg.html says that Iceberg support is experimental. Some other config entries mention that they are experimental.

Suggested change
"DataSource V2 API for better performance.")
"DataSource V2 API for better performance. This feature is experimental.")

.booleanConf
.createWithDefault(false)
.createWithDefault(true)

val COMET_ICEBERG_DATA_FILE_CONCURRENCY_LIMIT: ConfigEntry[Int] =
conf("spark.comet.scan.icebergNative.dataFileConcurrencyLimit")
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6 changes: 2 additions & 4 deletions docs/source/user-guide/latest/iceberg.md
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Expand Up @@ -29,8 +29,8 @@ then serialized to Comet's native execution engine (see
[PR #2528](https://github.com/apache/datafusion-comet/pull/2528)).

The example below uses Spark's package downloader to retrieve Comet 0.14.0 and Iceberg
1.8.1, but Comet has been tested with Iceberg 1.5, 1.7, 1.8, 1.9, and 1.10. The key configuration
to enable fully-native Iceberg is `spark.comet.scan.icebergNative.enabled=true`.
1.8.1, but Comet has been tested with Iceberg 1.5, 1.7, 1.8, 1.9, and 1.10. The native Iceberg
reader is enabled by default. To disable it, set `spark.comet.scan.icebergNative.enabled=false`.

```shell
$SPARK_HOME/bin/spark-shell \
Expand All @@ -43,7 +43,6 @@ $SPARK_HOME/bin/spark-shell \
--conf spark.plugins=org.apache.spark.CometPlugin \
--conf spark.shuffle.manager=org.apache.spark.sql.comet.execution.shuffle.CometShuffleManager \
--conf spark.sql.extensions=org.apache.comet.CometSparkSessionExtensions \
--conf spark.comet.scan.icebergNative.enabled=true \
--conf spark.comet.explainFallback.enabled=true \
--conf spark.memory.offHeap.enabled=true \
--conf spark.memory.offHeap.size=2g
Expand Down Expand Up @@ -120,7 +119,6 @@ $SPARK_HOME/bin/spark-shell \
--conf spark.plugins=org.apache.spark.CometPlugin \
--conf spark.shuffle.manager=org.apache.spark.sql.comet.execution.shuffle.CometShuffleManager \
--conf spark.sql.extensions=org.apache.comet.CometSparkSessionExtensions \
--conf spark.comet.scan.icebergNative.enabled=true \
--conf spark.comet.explainFallback.enabled=true \
--conf spark.memory.offHeap.enabled=true \
--conf spark.memory.offHeap.size=2g
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