Files
doris/be/src/vec/json/json_parser.cpp
lihangyu 37d1519316 [WIP](dynamic-table) support dynamic schema table (#16335)
Issue Number: close #16351

Dynamic schema table is a special type of table, it's schema change with loading procedure.Now we implemented this feature mainly for semi-structure data such as JSON, since JSON is schema self-described we could extract schema info from the original documents and inference the final type infomation.This speical table could reduce manual schema change operation and easily import semi-structure data and extends it's schema automatically.
2023-02-11 13:37:50 +08:00

265 lines
11 KiB
C++

// 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.
// This file is copied from
// https://github.com/ClickHouse/ClickHouse/blob/master/src/Common/JSONParsers/SimdJSONParser.cpp
// and modified by Doris
#include "vec/json/json_parser.h"
#include "vec/json/simd_json_parser.h"
namespace doris::vectorized {
template <typename ParserImpl>
bool JSONDataParser<ParserImpl>::extract_key(MutableColumns& columns, StringRef json,
const std::vector<StringRef>& keys,
const std::vector<ExtractType>& types) {
assert(types.size() == keys.size());
assert(columns.size() >= keys.size());
Element document;
if (!parser.parse(json.to_string_view(), document) || !document.isObject()) {
return false;
}
const auto& obj = document.getObject();
for (size_t x = 0; x < types.size(); ++x) {
Element element;
PathInData key_path(keys[x].to_string_view());
if (!obj.find(key_path, element) || element.isNull()) {
columns[x]->insert_default();
continue;
}
switch (types[x]) {
case ExtractType::ToString: {
if (element.isString()) {
auto str = element.getString();
columns[x]->insert_data(str.data(), str.size());
break;
}
auto str = castValueAsString(element);
columns[x]->insert_data(str.data(), str.size());
break;
}
default:
break;
}
}
return true;
}
template <typename ParserImpl>
std::optional<ParseResult> JSONDataParser<ParserImpl>::parse(const char* begin, size_t length) {
std::string_view json {begin, length};
Element document;
if (!parser.parse(json, document)) {
return {};
}
ParseContext context;
traverse(document, context);
ParseResult result;
result.values = std::move(context.values);
result.paths.reserve(context.paths.size());
for (auto&& path : context.paths) {
result.paths.emplace_back(std::move(path));
}
return result;
}
template <typename ParserImpl>
void JSONDataParser<ParserImpl>::traverse(const Element& element, ParseContext& ctx) {
// checkStackSize();
if (element.isObject()) {
traverseObject(element.getObject(), ctx);
} else if (element.isArray()) {
traverseArray(element.getArray(), ctx);
} else {
ctx.paths.push_back(ctx.builder.get_parts());
ctx.values.push_back(getValueAsField(element));
}
}
template <typename ParserImpl>
void JSONDataParser<ParserImpl>::traverseObject(const JSONObject& object, ParseContext& ctx) {
ctx.paths.reserve(ctx.paths.size() + object.size());
ctx.values.reserve(ctx.values.size() + object.size());
for (auto it = object.begin(); it != object.end(); ++it) {
const auto& [key, value] = *it;
ctx.builder.append(key, false);
traverse(value, ctx);
ctx.builder.pop_back();
}
}
template <typename ParserImpl>
void JSONDataParser<ParserImpl>::traverseArray(const JSONArray& array, ParseContext& ctx) {
/// Traverse elements of array and collect an array of fields by each path.
ParseArrayContext array_ctx;
array_ctx.total_size = array.size();
for (auto it = array.begin(); it != array.end(); ++it) {
traverseArrayElement(*it, array_ctx);
++array_ctx.current_size;
}
auto&& arrays_by_path = array_ctx.arrays_by_path;
if (arrays_by_path.empty()) {
ctx.paths.push_back(ctx.builder.get_parts());
ctx.values.push_back(Array());
} else {
ctx.paths.reserve(ctx.paths.size() + arrays_by_path.size());
ctx.values.reserve(ctx.values.size() + arrays_by_path.size());
for (auto it = arrays_by_path.begin(); it != arrays_by_path.end(); ++it) {
auto&& [path, path_array] = it->second;
/// Merge prefix path and path of array element.
ctx.paths.push_back(ctx.builder.append(path, true).get_parts());
ctx.values.push_back(std::move(path_array));
ctx.builder.pop_back(path.size());
}
}
}
template <typename ParserImpl>
void JSONDataParser<ParserImpl>::traverseArrayElement(const Element& element,
ParseArrayContext& ctx) {
ParseContext element_ctx;
traverse(element, element_ctx);
auto& [_, paths, values] = element_ctx;
size_t size = paths.size();
size_t keys_to_update = ctx.arrays_by_path.size();
for (size_t i = 0; i < size; ++i) {
if (values[i].is_null()) {
continue;
}
UInt128 hash = PathInData::get_parts_hash(paths[i]);
auto found = ctx.arrays_by_path.find(hash);
if (found != ctx.arrays_by_path.end()) {
auto& path_array = found->second.second;
assert(path_array.size() == ctx.current_size);
/// If current element of array is part of Nested,
/// collect its size or check it if the size of
/// the Nested has been already collected.
auto nested_key = getNameOfNested(paths[i], values[i]);
if (!nested_key.empty()) {
size_t array_size = get<const Array&>(values[i]).size();
auto& current_nested_sizes = ctx.nested_sizes_by_key[nested_key];
if (current_nested_sizes.size() == ctx.current_size) {
current_nested_sizes.push_back(array_size);
} else if (array_size != current_nested_sizes.back()) {
LOG(FATAL) << fmt::format("Array sizes mismatched ({} and {})", array_size,
current_nested_sizes.back());
}
}
path_array.push_back(std::move(values[i]));
--keys_to_update;
} else {
/// We found a new key. Add and empty array with current size.
Array path_array;
path_array.reserve(ctx.total_size);
path_array.resize(ctx.current_size);
auto nested_key = getNameOfNested(paths[i], values[i]);
if (!nested_key.empty()) {
size_t array_size = get<const Array&>(values[i]).size();
auto& current_nested_sizes = ctx.nested_sizes_by_key[nested_key];
if (current_nested_sizes.empty()) {
current_nested_sizes.resize(ctx.current_size);
} else {
/// If newly added element is part of the Nested then
/// resize its elements to keep correct sizes of Nested arrays.
for (size_t j = 0; j < ctx.current_size; ++j) {
path_array[j] = Array(current_nested_sizes[j]);
}
}
if (current_nested_sizes.size() == ctx.current_size) {
current_nested_sizes.push_back(array_size);
} else if (array_size != current_nested_sizes.back()) {
LOG(FATAL) << fmt::format("Array sizes mismatched ({} and {})", array_size,
current_nested_sizes.back());
}
}
path_array.push_back(std::move(values[i]));
auto& elem = ctx.arrays_by_path[hash];
elem.first = std::move(paths[i]);
elem.second = std::move(path_array);
}
}
/// If some of the keys are missed in current element,
/// add default values for them.
if (keys_to_update) {
fillMissedValuesInArrays(ctx);
}
}
template <typename ParserImpl>
void JSONDataParser<ParserImpl>::fillMissedValuesInArrays(ParseArrayContext& ctx) {
for (auto it = ctx.arrays_by_path.begin(); it != ctx.arrays_by_path.end(); ++it) {
auto& [path, path_array] = it->second;
assert(path_array.size() == ctx.current_size || path_array.size() == ctx.current_size + 1);
if (path_array.size() == ctx.current_size) {
bool inserted = tryInsertDefaultFromNested(ctx, path, path_array);
if (!inserted) {
path_array.emplace_back();
}
}
}
}
template <typename ParserImpl>
bool JSONDataParser<ParserImpl>::tryInsertDefaultFromNested(ParseArrayContext& ctx,
const PathInData::Parts& path,
Array& array) {
/// If there is a collected size of current Nested
/// then insert array of this size as a default value.
if (path.empty() || array.empty()) {
return false;
}
/// Last element is not Null, because otherwise this path wouldn't exist.
auto nested_key = getNameOfNested(path, array.back());
if (nested_key.empty()) {
return false;
}
auto mapped = ctx.nested_sizes_by_key.find(nested_key);
if (mapped == ctx.nested_sizes_by_key.end()) {
return false;
}
auto& current_nested_sizes = mapped->second;
assert(current_nested_sizes.size() == ctx.current_size ||
current_nested_sizes.size() == ctx.current_size + 1);
/// If all keys of Nested were missed then add a zero length.
if (current_nested_sizes.size() == ctx.current_size) {
current_nested_sizes.push_back(0);
}
size_t array_size = current_nested_sizes.back();
array.push_back(Array(array_size));
return true;
}
template <typename ParserImpl>
StringRef JSONDataParser<ParserImpl>::getNameOfNested(const PathInData::Parts& path,
const Field& value) {
if (value.get_type() != Field::Types::Array || path.empty()) {
return {};
}
/// Find first key that is marked as nested,
/// because we may have tuple of Nested and there could be
/// several arrays with the same prefix, but with independent sizes.
/// Consider we have array element with type `k2 Tuple(k3 Nested(...), k5 Nested(...))`
/// Then subcolumns `k2.k3` and `k2.k5` may have indepented sizes and we should extract
/// `k3` and `k5` keys instead of `k2`.
for (const auto& part : path) {
if (part.is_nested) {
return StringRef(part.key.data(), part.key.size());
}
}
return {};
}
template class JSONDataParser<SimdJSONParser>;
} // namespace doris::vectorized