apache/iceberg · error

Cannot drop partition field in non-Iceberg table: $table

Error message

Cannot drop partition field in non-Iceberg table: $table

What it means

DropPartitionFieldExec throws this UnsupportedOperationException when a DROP PARTITION FIELD statement targets a non-Iceberg table. Removing a partition field requires Iceberg's updateSpec().removeField() API, which only SparkTable instances wrapping Iceberg tables provide. Any other resolved table falls through to the throwing case.

Solutions

1. Check the provider with DESC TABLE EXTENDED and confirm iceberg.
2. Qualify with the Iceberg catalog: ALTER TABLE iceberg_catalog.db.tbl DROP PARTITION FIELD days(ts).
3. Register spark.sql.catalog.<name>=org.apache.iceberg.spark.SparkCatalog.
4. Apply the partition-field drop only to Iceberg tables.

Example fix

-- before
ALTER TABLE db.events DROP PARTITION FIELD days(ts); -- non-Iceberg
-- after
ALTER TABLE iceberg_catalog.db.events DROP PARTITION FIELD days(ts);

val spec = spark.sql("SELECT partition.spec() FROM cat.db.tbl").collect(); // fails early if not Iceberg

def supportsPartitionEvolution(t: org.apache.spark.sql.connector.catalog.Table): Boolean = t.isInstanceOf[org.apache.iceberg.spark.source.SparkTable]

try { spark.sql("ALTER TABLE cat.db.tbl DROP PARTITION FIELD days(ts)") } catch { case e: UnsupportedOperationException if e.getMessage.contains("non-Iceberg") => log.warn("partition evolution requires Iceberg") }

When it happens

Trigger: Running ALTER TABLE ... DROP PARTITION FIELD <transform> against a table that does not match `iceberg: SparkTable` in the plan, e.g. a Hive or Delta table.

Common situations: Partition-evolution DDL executed on the wrong table or wrong catalog; sessions where the identifier resolves through a non-Iceberg fallback catalog; mixed-provider namespaces.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

• Cannot add partition field to non-Iceberg table: $table
• Cannot replace partition field in non-Iceberg table: $table
• Cannot add partition field to non-Iceberg table: $table
• Cannot convert predicate to SQL
• Cannot convert term to SQL

AI-assisted analysis of apache/iceberg@86d9c8fc54 (2026-09-12). Data as JSON: /api/errors/fd4f798c68a81c46. Report an issue: GitHub.

Appendix: source

Thrown at spark/v3.5/spark-extensions/src/main/scala/org/apache/spark/sql/execution/datasources/v2/DropPartitionFieldExec.scala:58

        val schema = iceberg.table.schema
        transform match {
          case IdentityTransform(FieldReference(parts))
              if parts.size == 1 && schema.findField(parts.head) == null =>
            // the name is not present in the Iceberg schema, so it must be a partition field name, not a column name
            iceberg.table
              .updateSpec()
              .removeField(parts.head)
              .commit()

          case _ =>
            iceberg.table
              .updateSpec()
              .removeField(Spark3Util.toIcebergTerm(transform))
              .commit()
        }

      case table =>
        throw new UnsupportedOperationException(
          s"Cannot drop partition field in non-Iceberg table: $table")
    }

    Nil
  }

  override def simpleString(maxFields: Int): String = {
    s"DropPartitionField ${catalog.name}.${ident.quoted} ${transform.describe}"
  }
}

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