huaxingao opened a new pull request, #1723:
URL: https://github.com/apache/datafusion-comet/pull/1723
## Which issue does this PR close?
We original have CometConf.COMET_SCHEMA_EVOLUTION_ENABLED to set schema
evolution to true in Scan rule if the scan is Iceberg table scan. However, it
doesn't work for the following case:
```
sql("CREATE TABLE %s (id Int) USING iceberg", table1);
sql("INSERT INTO %s VALUES (1), (2), (3), (4)", table1);
sql("alter table %s alter column id type bigint", table1);
sql("SELECT * FROM %s", table1);
```
In this example, when executing SELECT * FROM table, Iceberg creates a Comet
ColumnReader and invokes TypeUtil.checkParquetType. This throws an exception
because the scan rule hasn't been applied yet, but the column type has already
changed to bigint.
```
org.apache.spark.sql.execution.datasources.SchemaColumnConvertNotSupportedException:
column: [id], physicalType: INT32, logicalType: bigint
at
app//org.apache.comet.parquet.TypeUtil.checkParquetType(TypeUtil.java:222)
at
app//org.apache.comet.parquet.AbstractColumnReader.<init>(AbstractColumnReader.java:93)
at
app//org.apache.comet.parquet.ColumnReader.<init>(ColumnReader.java:104)
at
app//org.apache.comet.parquet.Utils.getColumnReader(Utils.java:50)
```
Instead of enabling schema evolution in the scan rule, I will update
Utils.getColumnReader to accept a boolean supportsSchemaEvolution parameter and
pass true from the Iceberg side.
Closes #.
## Rationale for this change
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## What changes are included in this PR?
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## How are these changes tested?
I current test the new patch in Iceberg.
```
@Test
public void test() {
String table1 = tableName("test");
sql("CREATE TABLE %s (id Int) USING iceberg", table1);
sql("INSERT INTO %s VALUES (1), (2), (3), (4)", table1);
sql("alter table %s alter column id type bigint", table1);
List<Object[]> results = sql("SELECT * FROM %s", table1);
sql("DROP TABLE IF EXISTS %s", table1);
}
```
Without the fix, I got
```
org.apache.spark.sql.execution.datasources.SchemaColumnConvertNotSupportedException:
column: [id], physicalType: INT32, logicalType: bigint
at
app//org.apache.comet.parquet.TypeUtil.checkParquetType(TypeUtil.java:222)
at
app//org.apache.comet.parquet.AbstractColumnReader.<init>(AbstractColumnReader.java:93)
at
app//org.apache.comet.parquet.ColumnReader.<init>(ColumnReader.java:104)
at
app//org.apache.comet.parquet.Utils.getColumnReader(Utils.java:50)
at
app//org.apache.iceberg.spark.data.vectorized.CometColumnReader.reset(CometColumnReader.java:103)
```
With fix, the problem went away.
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