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feat: avro support applying field-ids based on name mapping #127

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21 changes: 16 additions & 5 deletions src/iceberg/avro/avro_reader.cc
Original file line number Diff line number Diff line change
Expand Up @@ -35,6 +35,7 @@
#include "iceberg/avro/avro_data_util_internal.h"
#include "iceberg/avro/avro_schema_util_internal.h"
#include "iceberg/avro/avro_stream_internal.h"
#include "iceberg/name_mapping.h"
#include "iceberg/schema_internal.h"
#include "iceberg/util/checked_cast.h"
#include "iceberg/util/macros.h"
Expand Down Expand Up @@ -96,16 +97,26 @@ class AvroReader::Impl {
// Create a base reader without setting reader schema to enable projection.
auto base_reader =
std::make_unique<::avro::DataFileReaderBase>(std::move(input_stream));
const ::avro::ValidSchema& file_schema = base_reader->dataSchema();
::avro::ValidSchema file_schema = base_reader->dataSchema();

// Validate field ids in the file schema.
HasIdVisitor has_id_visitor;
ICEBERG_RETURN_UNEXPECTED(has_id_visitor.Visit(file_schema));

if (has_id_visitor.HasNoIds()) {
// TODO(gangwu): support applying field-ids based on name mapping
return NotImplemented("Avro file schema has no field IDs");
}
if (!has_id_visitor.AllHaveIds()) {
// Apply field IDs based on name mapping if available
if (options.name_mapping) {
ICEBERG_ASSIGN_OR_RAISE(
auto new_root_node,
MakeAvroNodeWithFieldIds(file_schema.root(), *options.name_mapping));

// Update the file schema to use the new schema with field IDs
file_schema = ::avro::ValidSchema(new_root_node);
} else {
return InvalidSchema(
"Avro file schema has no field IDs and no name mapping provided");
}
} else if (!has_id_visitor.AllHaveIds()) {
return InvalidSchema("Not all fields in the Avro file schema have field IDs");
}

Expand Down
276 changes: 276 additions & 0 deletions src/iceberg/avro/avro_schema_util.cc
Original file line number Diff line number Diff line change
Expand Up @@ -31,7 +31,9 @@

#include "iceberg/avro/avro_register.h"
#include "iceberg/avro/avro_schema_util_internal.h"
#include "iceberg/avro/constants.h"
#include "iceberg/metadata_columns.h"
#include "iceberg/name_mapping.h"
#include "iceberg/schema.h"
#include "iceberg/schema_util_internal.h"
#include "iceberg/util/formatter.h"
Expand Down Expand Up @@ -773,4 +775,278 @@ Result<SchemaProjection> Project(const Schema& expected_schema,
return SchemaProjection{std::move(field_projection.children)};
}

namespace {

Result<::avro::NodePtr> CreateRecordNodeWithFieldIds(const ::avro::NodePtr& original_node,
const MappedField& field) {
auto new_record_node = std::make_shared<::avro::NodeRecord>();
new_record_node->setName(original_node->name());

for (size_t i = 0; i < original_node->leaves(); ++i) {
if (i >= original_node->names()) {
return InvalidSchema("Index {} is out of bounds for names (size: {})", i,
original_node->names());
}
const std::string& field_name = original_node->nameAt(i);
::avro::NodePtr field_node = original_node->leafAt(i);

// TODO(liuxiaoyu): Add support for case sensitivity in name matching.
// Try to find nested field by name
const MappedField* nested_field = nullptr;
if (field.nested_mapping) {
auto fields_span = field.nested_mapping->fields();
for (const auto& f : fields_span) {
if (f.names.find(field_name) != f.names.end()) {
nested_field = &f;
break;
}
}
}
Comment on lines +795 to +804
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Suggested change
const MappedField* nested_field = nullptr;
if (field.nested_mapping) {
auto fields_span = field.nested_mapping->fields();
for (const auto& f : fields_span) {
if (f.names.find(field_name) != f.names.end()) {
nested_field = &f;
break;
}
}
}
const MappedField* nested_field = nullptr;
auto field_id_opt = field.Id(field_name);
if (field_id_opt.has_value()) {
nested_field = &(field.Field(field_id_opt.value()).value().get());
}

This is not a required suggestion but I just found that the refactoring above does the same thing. Perhaps we should extend MappedFields by adding a new function to return a std::optional<MappedFieldConstRef> by finding a field name.


if (nested_field) {
// Check if field_id is present
if (!nested_field->field_id.has_value()) {
return InvalidSchema("Field ID is missing for field '{}' in nested mapping",
field_name);
}

// Preserve existing custom attributes for this field
::avro::CustomAttributes attributes;
if (i < original_node->customAttributes()) {
// Copy all existing attributes from the original node
const auto& original_attrs = original_node->customAttributesAt(i);
const auto& existing_attrs = original_attrs.attributes();
for (const auto& attr_pair : existing_attrs) {
Comment on lines +817 to +819
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Suggested change
const auto& original_attrs = original_node->customAttributesAt(i);
const auto& existing_attrs = original_attrs.attributes();
for (const auto& attr_pair : existing_attrs) {
for (const auto& attr_pair : original_node->customAttributesAt(i).attributes()) {

// Copy each existing attribute to preserve original metadata
attributes.addAttribute(attr_pair.first, attr_pair.second, false);
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Suggested change
attributes.addAttribute(attr_pair.first, attr_pair.second, false);
attributes.addAttribute(attr_pair.first, attr_pair.second, /*addQuote=*/false);

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For better readability.

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Please add this comment.

}
}

// Add field ID attribute to the new node (preserving existing attributes)
attributes.addAttribute(std::string(kFieldIdProp),
std::to_string(nested_field->field_id.value()), false);

new_record_node->addCustomAttributesForField(attributes);

// Recursively apply field IDs to nested fields
ICEBERG_ASSIGN_OR_RAISE(auto new_nested_node,
MakeAvroNodeWithFieldIds(field_node, *nested_field));
new_record_node->addName(field_name);
new_record_node->addLeaf(new_nested_node);
} else {
// If no nested field found, this is an error
return InvalidSchema("Field '{}' not found in nested mapping", field_name);
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It is much better to return error immediately after we fail to find the field id. Then we don't need the large if branch at line 817.

}
}

return new_record_node;
}

Result<::avro::NodePtr> CreateArrayNodeWithFieldIds(const ::avro::NodePtr& original_node,
const MappedField& field) {
if (original_node->leaves() != 1) {
return InvalidSchema("Array type must have exactly one leaf");
}

auto new_array_node = std::make_shared<::avro::NodeArray>();

// Check if this is a map represented as array
if (HasMapLogicalType(original_node)) {
ICEBERG_ASSIGN_OR_RAISE(auto new_element_node,
MakeAvroNodeWithFieldIds(original_node->leafAt(0), field));
new_array_node->addLeaf(new_element_node);
return new_array_node;
}

// For regular arrays, try to find element field ID from nested mapping
const MappedField* element_field = nullptr;
if (field.nested_mapping) {
auto fields_span = field.nested_mapping->fields();
for (const auto& f : fields_span) {
if (f.names.find(std::string(kElement)) != f.names.end()) {
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Do we actually need to find the field name of a map or array? IIUC, the field name mapping should only apply to struct fields. We can blindly use the child nested_mapping.

element_field = &f;
break;
}
}
}

if (element_field) {
// Check if field_id is present
if (!element_field->field_id.has_value()) {
return InvalidSchema("Field ID is missing for element field in array");
}

ICEBERG_ASSIGN_OR_RAISE(
auto new_element_node,
MakeAvroNodeWithFieldIds(original_node->leafAt(0), *element_field));
new_array_node->addLeaf(new_element_node);
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Shouldn't we add element_field->field_id to the custom attributes?


// Add element field ID as custom attribute
::avro::CustomAttributes element_attributes;
element_attributes.addAttribute(std::string(kFieldIdProp),
std::to_string(*element_field->field_id), false);
new_array_node->addCustomAttributesForField(element_attributes);
} else {
// If no element field found, this is an error
return InvalidSchema("Element field not found in nested mapping for array");
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Ditto

}

return new_array_node;
}

Result<::avro::NodePtr> CreateMapNodeWithFieldIds(const ::avro::NodePtr& original_node,
const MappedField& field) {
if (original_node->leaves() != 2) {
return InvalidSchema("Map type must have exactly two leaves");
}

auto new_map_node = std::make_shared<::avro::NodeMap>();

// For map types, we need to extract key and value field mappings from the nested
// mapping
if (!field.nested_mapping) {
return InvalidSchema("Map type requires nested mapping for key and value fields");
}

// Find key and value field mappings by name
std::optional<int32_t> key_id = field.nested_mapping->Id("key");
std::optional<int32_t> value_id = field.nested_mapping->Id("value");

if (!key_id || !value_id) {
return InvalidSchema("Map type requires both 'key' and 'value' field mappings");
}

std::optional<MappedFieldConstRef> key_field_ref = field.nested_mapping->Field(*key_id);
std::optional<MappedFieldConstRef> value_field_ref =
field.nested_mapping->Field(*value_id);

if (!key_field_ref || !value_field_ref) {
return InvalidSchema("Map type requires both key and value field mappings");
}

const auto& key_mapped_field = key_field_ref->get();
const auto& value_mapped_field = value_field_ref->get();

if (!key_mapped_field.field_id || !value_mapped_field.field_id) {
return InvalidSchema("Map key and value fields must have field IDs");
}

// Create key field with mapped field ID
MappedField key_field;
key_field.field_id = *key_mapped_field.field_id;
key_field.nested_mapping = key_mapped_field.nested_mapping;

// Create value field with mapped field ID
MappedField value_field;
value_field.field_id = *value_mapped_field.field_id;
value_field.nested_mapping = value_mapped_field.nested_mapping;

// Add key and value nodes
ICEBERG_ASSIGN_OR_RAISE(auto new_key_node,
MakeAvroNodeWithFieldIds(original_node->leafAt(0), key_field));
ICEBERG_ASSIGN_OR_RAISE(
auto new_value_node,
MakeAvroNodeWithFieldIds(original_node->leafAt(1), value_field));
new_map_node->addLeaf(new_key_node);
new_map_node->addLeaf(new_value_node);

// Preserve existing custom attributes from the original node and add field ID
// attributes Copy existing attributes from the original node (if any)
if (original_node->customAttributes() > 0) {
const auto& original_attrs = original_node->customAttributesAt(0);
const auto& existing_attrs = original_attrs.attributes();
for (const auto& attr_pair : existing_attrs) {
// Copy each existing attribute to preserve original metadata
::avro::CustomAttributes attributes;
attributes.addAttribute(attr_pair.first, attr_pair.second, false);
new_map_node->addCustomAttributesForField(attributes);
}
}

::avro::CustomAttributes key_attributes;
key_attributes.addAttribute(std::string(kFieldIdProp),
std::to_string(*key_mapped_field.field_id), false);
new_map_node->addCustomAttributesForField(key_attributes);

::avro::CustomAttributes value_attributes;
value_attributes.addAttribute(std::string(kFieldIdProp),
std::to_string(*value_mapped_field.field_id), false);
new_map_node->addCustomAttributesForField(value_attributes);

return new_map_node;
}

Result<::avro::NodePtr> CreateUnionNodeWithFieldIds(const ::avro::NodePtr& original_node,
const MappedField& field) {
if (original_node->leaves() != 2) {
return InvalidSchema("Union type must have exactly two branches");
}

const auto& branch_0 = original_node->leafAt(0);
const auto& branch_1 = original_node->leafAt(1);

bool branch_0_is_null = (branch_0->type() == ::avro::AVRO_NULL);
bool branch_1_is_null = (branch_1->type() == ::avro::AVRO_NULL);

if (branch_0_is_null && !branch_1_is_null) {
// branch_0 is null, branch_1 is not null
ICEBERG_ASSIGN_OR_RAISE(auto new_branch_1, MakeAvroNodeWithFieldIds(branch_1, field));
auto new_union_node = std::make_shared<::avro::NodeUnion>();
new_union_node->addLeaf(branch_0); // null branch
new_union_node->addLeaf(new_branch_1);
return new_union_node;
} else if (!branch_0_is_null && branch_1_is_null) {
// branch_0 is not null, branch_1 is null
ICEBERG_ASSIGN_OR_RAISE(auto new_branch_0, MakeAvroNodeWithFieldIds(branch_0, field));
auto new_union_node = std::make_shared<::avro::NodeUnion>();
new_union_node->addLeaf(new_branch_0);
new_union_node->addLeaf(branch_1); // null branch
return new_union_node;
} else if (branch_0_is_null && branch_1_is_null) {
// Both branches are null - this is invalid
return InvalidSchema("Union type cannot have two null branches");
} else {
// Neither branch is null - this is invalid
return InvalidSchema("Union type must have exactly one null branch");
}
}

} // namespace

Result<::avro::NodePtr> MakeAvroNodeWithFieldIds(const ::avro::NodePtr& original_node,
const MappedField& mapped_field) {
switch (original_node->type()) {
case ::avro::AVRO_RECORD:
return CreateRecordNodeWithFieldIds(original_node, mapped_field);
case ::avro::AVRO_ARRAY:
return CreateArrayNodeWithFieldIds(original_node, mapped_field);
case ::avro::AVRO_MAP:
return CreateMapNodeWithFieldIds(original_node, mapped_field);
case ::avro::AVRO_UNION:
return CreateUnionNodeWithFieldIds(original_node, mapped_field);
case ::avro::AVRO_BOOL:
case ::avro::AVRO_INT:
case ::avro::AVRO_LONG:
case ::avro::AVRO_FLOAT:
case ::avro::AVRO_DOUBLE:
case ::avro::AVRO_STRING:
case ::avro::AVRO_BYTES:
case ::avro::AVRO_FIXED:
// For primitive types, just return a copy
return original_node;
case ::avro::AVRO_NULL:
case ::avro::AVRO_ENUM:
default:
return InvalidSchema("Unsupported Avro type for field ID application: {}",
ToString(original_node));
}
}

Result<::avro::NodePtr> MakeAvroNodeWithFieldIds(const ::avro::NodePtr& original_node,
const NameMapping& mapping) {
MappedField mapped_field;
mapped_field.nested_mapping = std::make_shared<MappedFields>(mapping.AsMappedFields());
return MakeAvroNodeWithFieldIds(original_node, mapped_field);
}

} // namespace iceberg::avro
15 changes: 15 additions & 0 deletions src/iceberg/avro/avro_schema_util_internal.h
Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,7 @@

#include <avro/Node.hh>

#include "iceberg/name_mapping.h"
#include "iceberg/result.h"
#include "iceberg/schema_util.h"
#include "iceberg/type.h"
Expand Down Expand Up @@ -148,4 +149,18 @@ std::string ToString(const ::avro::LogicalType::Type& logical_type);
/// \return True if the node has a map logical type, false otherwise.
bool HasMapLogicalType(const ::avro::NodePtr& node);

/// \brief Create a new Avro node with field IDs from name mapping.
/// \param original_node The original Avro node to copy.
/// \param mapped_field The mapped field to apply field IDs from.
/// \return A new Avro node with field IDs applied, or an error.
Result<::avro::NodePtr> MakeAvroNodeWithFieldIds(const ::avro::NodePtr& original_node,
const MappedField& mapped_field);

/// \brief Create a new Avro node with field IDs from name mapping.
/// \param original_node The original Avro node to copy.
/// \param mapping The name mapping to apply field IDs from.
/// \return A new Avro node with field IDs applied, or an error.
Result<::avro::NodePtr> MakeAvroNodeWithFieldIds(const ::avro::NodePtr& original_node,
const NameMapping& mapping);

} // namespace iceberg::avro
34 changes: 34 additions & 0 deletions src/iceberg/avro/constants.h
Original file line number Diff line number Diff line change
@@ -0,0 +1,34 @@
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/

#pragma once

#include <string_view>

namespace iceberg::avro {

// Avro logical type constants
constexpr std::string_view kMapLogicalType = "map";

// Name mapping field constants
constexpr std::string_view kElement = "element";
constexpr std::string_view kKey = "key";
constexpr std::string_view kValue = "value";

} // namespace iceberg::avro
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