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[lake/iceberg] Support ADD COLUMN schema evolution for Iceberg lake catalog #2593

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[lake/iceberg] Support ADD COLUMN schema evolution for Iceberg lake catalog #2593

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167 changes: 147 additions & 20 deletions ...ke/fluss-lake-iceberg/src/main/java/org/apache/fluss/lake/iceberg/IcebergLakeCatalog.java
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@

import org.apache.fluss.annotation.VisibleForTesting;
import org.apache.fluss.config.Configuration;
import org.apache.fluss.exception.InvalidAlterTableException;
import org.apache.fluss.exception.InvalidTableException;
import org.apache.fluss.exception.TableAlreadyExistException;
import org.apache.fluss.exception.TableNotExistException;
Expand All @@ -36,6 +37,7 @@
import org.apache.iceberg.Table;
import org.apache.iceberg.TableProperties;
import org.apache.iceberg.UpdateProperties;
import org.apache.iceberg.UpdateSchema;
import org.apache.iceberg.catalog.Catalog;
import org.apache.iceberg.catalog.Namespace;
import org.apache.iceberg.catalog.SupportsNamespaces;
Expand All @@ -44,8 +46,11 @@
import org.apache.iceberg.exceptions.NoSuchNamespaceException;
import org.apache.iceberg.exceptions.NoSuchTableException;
import org.apache.iceberg.types.Type;
import org.apache.iceberg.types.TypeUtil;
import org.apache.iceberg.types.Types;

import javax.annotation.Nullable;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
Expand Down Expand Up @@ -133,35 +138,157 @@ public void alterTable(TablePath tablePath, List<TableChange> tableChanges, Cont
throws TableNotExistException {
try {
Table table = icebergCatalog.loadTable(toIcebergTableIdentifier(tablePath));
UpdateProperties updateProperties = table.updateProperties();
for (TableChange tableChange : tableChanges) {
if (tableChange instanceof TableChange.SetOption) {
TableChange.SetOption option = (TableChange.SetOption) tableChange;
checkArgument(
!RESERVED_PROPERTIES.contains(option.getKey()),
"Cannot set table property '%s'",
option.getKey());
updateProperties.set(
convertFlussPropertyKeyToIceberg(option.getKey()), option.getValue());
} else if (tableChange instanceof TableChange.ResetOption) {
TableChange.ResetOption option = (TableChange.ResetOption) tableChange;
checkArgument(
!RESERVED_PROPERTIES.contains(option.getKey()),
"Cannot reset table property '%s'",
option.getKey());
updateProperties.remove(convertFlussPropertyKeyToIceberg(option.getKey()));

List<TableChange> schemaChanges = new ArrayList<>();
List<TableChange> propertyChanges = new ArrayList<>();
for (TableChange change : tableChanges) {
if (change instanceof TableChange.SchemaChange) {
schemaChanges.add(change);
} else {
throw new UnsupportedOperationException(
"Unsupported table change: " + tableChange.getClass());
propertyChanges.add(change);
}
}

updateProperties.commit();
if (!schemaChanges.isEmpty()) {
applySchemaChanges(table, schemaChanges, context);
}

if (!propertyChanges.isEmpty()) {
applyPropertyChanges(table, propertyChanges);
}
} catch (NoSuchTableException e) {
throw new TableNotExistException("Table " + tablePath + " does not exist.");
}
}

private void applyPropertyChanges(Table table, List<TableChange> propertyChanges) {
UpdateProperties updateProperties = table.updateProperties();
for (TableChange tableChange : propertyChanges) {
if (tableChange instanceof TableChange.SetOption) {
TableChange.SetOption option = (TableChange.SetOption) tableChange;
checkArgument(
!RESERVED_PROPERTIES.contains(option.getKey()),
"Cannot set table property '%s'",
option.getKey());
updateProperties.set(
convertFlussPropertyKeyToIceberg(option.getKey()), option.getValue());
} else if (tableChange instanceof TableChange.ResetOption) {
TableChange.ResetOption option = (TableChange.ResetOption) tableChange;
checkArgument(
!RESERVED_PROPERTIES.contains(option.getKey()),
"Cannot reset table property '%s'",
option.getKey());
updateProperties.remove(convertFlussPropertyKeyToIceberg(option.getKey()));
} else {
throw new UnsupportedOperationException(
"Unsupported table change: " + tableChange.getClass());
}
}
updateProperties.commit();
}

private void applySchemaChanges(Table table, List<TableChange> schemaChanges, Context context) {
Schema currentIcebergSchema = table.schema();

// Check schema compatibility to handle crash recovery idempotency.
boolean skipAddColumns;
if (isIcebergSchemaCompatible(currentIcebergSchema, context.getCurrentTable())) {
// Iceberg schema matches current Fluss schema, apply all changes.
skipAddColumns = false;
} else if (isIcebergSchemaCompatible(currentIcebergSchema, context.getExpectedTable())) {
// Iceberg schema already matches expected (post-alter) schema,
// skip AddColumn changes since they were already applied.
skipAddColumns = true;
} else {
throw new InvalidAlterTableException(
String.format(
"Iceberg schema is not compatible with Fluss schema: "
+ "Iceberg schema: %s, Fluss schema: %s. "
+ "therefore you need to add the diff columns all at once, "
+ "rather than applying other table changes: %s.",
currentIcebergSchema,
context.getCurrentTable().getSchema(),
schemaChanges));
}

UpdateSchema updateSchema = table.updateSchema();
String firstSystemColumnName = SYSTEM_COLUMNS.keySet().iterator().next();
boolean hasChanges = false;

for (TableChange tableChange : schemaChanges) {
if (tableChange instanceof TableChange.AddColumn) {
if (skipAddColumns) {
continue;
}
TableChange.AddColumn addColumn = (TableChange.AddColumn) tableChange;

if (!(addColumn.getPosition() instanceof TableChange.Last)) {
throw new UnsupportedOperationException(
"Only support to add column at last for iceberg table.");
}

org.apache.fluss.types.DataType flussDataType = addColumn.getDataType();
if (!flussDataType.isNullable()) {
throw new UnsupportedOperationException(
"Only support to add nullable column for iceberg table.");
}

Type icebergType = flussDataType.accept(new FlussDataTypeToIcebergDataType());
updateSchema.addColumn(addColumn.getName(), icebergType, addColumn.getComment());
updateSchema.moveBefore(addColumn.getName(), firstSystemColumnName);
hasChanges = true;
} else {
throw new UnsupportedOperationException(
"Unsupported table change: " + tableChange.getClass());
}
}

if (hasChanges) {
updateSchema.commit();
}
}

/**
* Checks whether the current Iceberg schema is compatible with the given Fluss table
* descriptor. Compatibility means the user columns and system columns match in name, type, and
* nullability (ignoring Iceberg-assigned field IDs).
*
* <p>Iceberg reassigns field IDs during table creation, so the IDs in the stored schema differ
* from those we generate via {@link #convertToIcebergSchema}. We normalize both schemas to the
* same fresh ID space using {@link TypeUtil#assignIncreasingFreshIds} before comparing, so that
* {@link Type#equals} works correctly for all types including complex ones (Map, List, Struct).
*/
@VisibleForTesting
boolean isIcebergSchemaCompatible(
Schema icebergSchema, @Nullable TableDescriptor flussTableDescriptor) {
if (flussTableDescriptor == null) {
return false;
}
// isPkTable=false: identifier fields don't affect the comparison
Schema expectedSchema = convertToIcebergSchema(flussTableDescriptor, false);

Schema normalizedIceberg = TypeUtil.assignIncreasingFreshIds(icebergSchema);
Schema normalizedExpected = TypeUtil.assignIncreasingFreshIds(expectedSchema);

List<Types.NestedField> currentFields = normalizedIceberg.columns();
List<Types.NestedField> expectedFields = normalizedExpected.columns();

if (currentFields.size() != expectedFields.size()) {
return false;
}

for (int i = 0; i < currentFields.size(); i++) {
Types.NestedField current = currentFields.get(i);
Types.NestedField expected = expectedFields.get(i);
if (!current.name().equals(expected.name())
|| !current.type().equals(expected.type())
|| current.isOptional() != expected.isOptional()) {
return false;
}
}
return true;
}

private TableIdentifier toIcebergTableIdentifier(TablePath tablePath) {
return TableIdentifier.of(tablePath.getDatabaseName(), tablePath.getTableName());
}
Expand Down
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