[core] Fix blob read failure after alter table and compaction

paimon-core/src/main/java/org/apache/paimon/operation/DataEvolutionSplitRead.java

@@ -548,9 +548,11 @@ void add(DataFileMeta file) {
                     }
                 }
                 if (!files.isEmpty()) {
-                    checkArgument(
-                            file.schemaId() == files.get(0).schemaId(),
-                            "All files in this bunch should have the same schema id.");
+                    if (!isBlobFile(file.fileName())) {
+                        checkArgument(
+                                file.schemaId() == files.get(0).schemaId(),
+                                "All files in this bunch should have the same schema id.");
+                    }
                     checkArgument(
                             file.writeCols().equals(files.get(0).writeCols()),
                             "All files in this bunch should have the same write columns.");

paimon-core/src/main/java/org/apache/paimon/schema/SchemaManager.java

@@ -42,6 +42,7 @@
 import org.apache.paimon.types.DataField;
 import org.apache.paimon.types.DataType;
 import org.apache.paimon.types.DataTypeCasts;
+import org.apache.paimon.types.DataTypeRoot;
 import org.apache.paimon.types.MapType;
 import org.apache.paimon.types.ReassignFieldId;
 import org.apache.paimon.types.RowType;
@@ -404,6 +405,7 @@ protected void updateLastColumn(
             } else if (change instanceof RenameColumn) {
                 RenameColumn rename = (RenameColumn) change;
                 assertNotUpdatingPartitionKeys(oldTableSchema, rename.fieldNames(), "rename");
+                assertNotRenamingBlobColumn(newFields, rename.fieldNames());
                 new NestedColumnModifier(rename.fieldNames(), lazyIdentifier) {
                     @Override
                     protected void updateLastColumn(
@@ -908,6 +910,19 @@ private static void assertNotUpdatingPrimaryKeys(
         }
     }
 
+    private static void assertNotRenamingBlobColumn(List<DataField> fields, String[] fieldNames) {
+        if (fieldNames.length > 1) {
+            return;
+        }
+        String fieldName = fieldNames[0];
+        for (DataField field : fields) {
+            if (field.name().equals(fieldName) && field.type().is(DataTypeRoot.BLOB)) {
+                throw new UnsupportedOperationException(
+                        String.format("Cannot rename BLOB column: [%s]", fieldName));
+            }
+        }
+    }
+
     private abstract static class NestedColumnModifier {
 
         private final String[] updateFieldNames;

paimon-core/src/test/java/org/apache/paimon/JavaPyE2ETest.java

@@ -791,6 +791,86 @@ public void testJavaWriteCompressedTextAppendTable() throws Exception {
         }
     }
 
+    @Test
+    @EnabledIfSystemProperty(named = "run.e2e.tests", matches = "true")
+    public void testBlobWriteAlterCompact() throws Exception {
+        Identifier identifier = identifier("blob_alter_compact_test");
+        catalog.dropTable(identifier, true);
+        Schema schema =
+                Schema.newBuilder()
+                        .column("f0", DataTypes.INT())
+                        .column("f1", DataTypes.STRING())
+                        .column("f2", DataTypes.BLOB())
+                        .option("target-file-size", "100 MB")
+                        .option("row-tracking.enabled", "true")
+                        .option("data-evolution.enabled", "true")
+                        .option("compaction.min.file-num", "2")
+                        .option("bucket", "-1")
+                        .build();
+        catalog.createTable(identifier, schema, false);
+
+        byte[] blobBytes = new byte[1024];
+        new java.util.Random(42).nextBytes(blobBytes);
+
+        // Batch 1: write with schemaId=0
+        FileStoreTable table = (FileStoreTable) catalog.getTable(identifier);
+        StreamTableWrite write =
+                table.newStreamWriteBuilder().withCommitUser(commitUser).newWrite();
+        StreamTableCommit commit = table.newCommit(commitUser);
+        for (int i = 0; i < 100; i++) {
+            write.write(
+                    GenericRow.of(
+                            1,
+                            BinaryString.fromString("batch1"),
+                            new org.apache.paimon.data.BlobData(blobBytes)));
+        }
+        commit.commit(0, write.prepareCommit(false, 0));
+
+        // ALTER TABLE SET -> schemaId becomes 1
+        catalog.alterTable(
+                identifier,
+                org.apache.paimon.schema.SchemaChange.setOption("snapshot.num-retained.min", "5"),
+                false);
+
+        // Batch 2: write with schemaId=1
+        table = (FileStoreTable) catalog.getTable(identifier);
+        write = table.newStreamWriteBuilder().withCommitUser(commitUser).newWrite();
+        commit = table.newCommit(commitUser);
+        for (int i = 0; i < 100; i++) {
+            write.write(
+                    GenericRow.of(
+                            2,
+                            BinaryString.fromString("batch2"),
+                            new org.apache.paimon.data.BlobData(blobBytes)));
+        }
+        commit.commit(1, write.prepareCommit(false, 1));
+        write.close();
+        commit.close();
+
+        // Compact
+        table = (FileStoreTable) catalog.getTable(identifier);
+        org.apache.paimon.append.dataevolution.DataEvolutionCompactCoordinator coordinator =
+                new org.apache.paimon.append.dataevolution.DataEvolutionCompactCoordinator(
+                        table, false, false);
+        List<org.apache.paimon.append.dataevolution.DataEvolutionCompactTask> tasks =
+                coordinator.plan();
+        assertThat(tasks.size()).isGreaterThan(0);
+        List<org.apache.paimon.table.sink.CommitMessage> compactMessages = new ArrayList<>();
+        for (org.apache.paimon.append.dataevolution.DataEvolutionCompactTask task : tasks) {
+            compactMessages.add(task.doCompact(table, commitUser));
+        }
+        StreamTableCommit compactCommit = table.newCommit(commitUser);
+        compactCommit.commit(2, compactMessages);
+        compactCommit.close();
+
+        FileStoreTable readTable = (FileStoreTable) catalog.getTable(identifier);
+        List<Split> splits = new ArrayList<>(readTable.newSnapshotReader().read().dataSplits());
+        TableRead read = readTable.newRead();
+        RowType rowType = readTable.rowType();
+        List<String> res = getResult(read, splits, row -> internalRowToString(row, rowType));
+        assertThat(res).hasSize(200);
+    }
+
     // Helper method from TableTestBase
     protected Identifier identifier(String tableName) {
         return new Identifier(database, tableName);