Add support for truncate statement in Iceberg

Author: ebyhr

plugin/trino-iceberg/src/main/java/io/trino/plugin/iceberg/IcebergMetadata.java

@@ -306,6 +306,7 @@
 import static org.apache.iceberg.TableProperties.DELETE_ISOLATION_LEVEL_DEFAULT;
 import static org.apache.iceberg.TableProperties.FORMAT_VERSION;
 import static org.apache.iceberg.TableProperties.WRITE_LOCATION_PROVIDER_IMPL;
+import static org.apache.iceberg.expressions.Expressions.alwaysTrue;
 import static org.apache.iceberg.types.TypeUtil.indexParents;
 import static org.apache.iceberg.util.LocationUtil.stripTrailingSlash;
 import static org.apache.iceberg.util.SnapshotUtil.schemaFor;
@@ -2551,6 +2552,16 @@ public OptionalLong executeDelete(ConnectorSession session, ConnectorTableHandle
         return OptionalLong.of(deletedRecords - removedPositionDeletes - removedEqualityDeletes);
     }
 
+    @Override
+    public void truncateTable(ConnectorSession session, ConnectorTableHandle tableHandle)
+    {
+        IcebergTableHandle table = checkValidTableHandle(tableHandle);
+        Table icebergTable = catalog.loadTable(session, table.getSchemaTableName());
+        DeleteFiles deleteFiles = icebergTable.newDelete()
+                .deleteFromRowFilter(alwaysTrue());
+        commit(deleteFiles, session);
+    }
+
     public void rollback()
     {
         // TODO: cleanup open transaction

plugin/trino-iceberg/src/test/java/io/trino/plugin/iceberg/BaseIcebergConnectorSmokeTest.java

@@ -84,8 +84,7 @@ public void initFileSystem()
     protected boolean hasBehavior(TestingConnectorBehavior connectorBehavior)
     {
         return switch (connectorBehavior) {
-            case SUPPORTS_TOPN_PUSHDOWN,
-                 SUPPORTS_TRUNCATE -> false;
+            case SUPPORTS_TOPN_PUSHDOWN -> false;
             default -> super.hasBehavior(connectorBehavior);
         };
     }

plugin/trino-iceberg/src/test/java/io/trino/plugin/iceberg/BaseIcebergConnectorTest.java

@@ -225,8 +225,7 @@ protected boolean hasBehavior(TestingConnectorBehavior connectorBehavior)
                  SUPPORTS_REPORTING_WRITTEN_BYTES -> true;
             case SUPPORTS_ADD_COLUMN_NOT_NULL_CONSTRAINT,
                  SUPPORTS_RENAME_MATERIALIZED_VIEW_ACROSS_SCHEMAS,
-                 SUPPORTS_TOPN_PUSHDOWN,
-                 SUPPORTS_TRUNCATE -> false;
+                 SUPPORTS_TOPN_PUSHDOWN -> false;
             default -> super.hasBehavior(connectorBehavior);
         };
     }
@@ -6227,6 +6226,15 @@ public void testEmptyDelete()
         assertUpdate("DROP TABLE " + tableName);
     }
 
+    @Test
+    public void testEmptyFilesTruncate()
+    {
+        try (TestTable table = new TestTable(getQueryRunner()::execute, "test_empty_files_truncate_", "AS SELECT 1 AS id")) {
+            assertUpdate("TRUNCATE TABLE " + table.getName());
+            assertQueryReturnsEmptyResult("SELECT * FROM \"" + table.getName() + "$files\"");
+        }
+    }
+
     @Test
     public void testModifyingOldSnapshotIsNotPossible()
     {
@@ -7298,7 +7306,7 @@ public void testCorruptedTableLocation()
         assertQueryFails("UPDATE " + tableName + " SET country = 'AUSTRIA'", "Metadata not found in metadata location for table " + schemaTableName);
         assertQueryFails("DELETE FROM " + tableName, "Metadata not found in metadata location for table " + schemaTableName);
         assertQueryFails("MERGE INTO  " + tableName + " USING (SELECT 1 a) input ON true WHEN MATCHED THEN DELETE", "Metadata not found in metadata location for table " + schemaTableName);
-        assertQueryFails("TRUNCATE TABLE " + tableName, "This connector does not support truncating tables");
+        assertQueryFails("TRUNCATE TABLE " + tableName, "Metadata not found in metadata location for table " + schemaTableName);
         assertQueryFails("COMMENT ON TABLE " + tableName + " IS NULL", "Metadata not found in metadata location for table " + schemaTableName);
         assertQueryFails("COMMENT ON COLUMN " + tableName + ".foo IS NULL", "Metadata not found in metadata location for table " + schemaTableName);
         assertQueryFails("CALL iceberg.system.rollback_to_snapshot(CURRENT_SCHEMA, '" + tableName + "', 8954597067493422955)", "Metadata not found in metadata location for table " + schemaTableName);