Files
doris/be/src/exec/es/es_scroll_parser.cpp
令狐少侠 5a57ecca15 [Doris On ES]fix bug of query failed in doc_value_mode when fields have none value (#3513)
#3479 

Here I try to explain the cause of the problem and how to fix it.

**The Cause of The problem**
Take the case in issue(#3479 ) as an example:
The general results are as follows:
```
GET table/_doc/_search
{"query":{"match_all":{}},"stored_fields":"_none_","docvalue_fields":["k1"],"sort":["_doc"],"size":100}

{
  "took": 6,
  "timed_out": false,
  "_shards": {
    ……
  },
  "hits": {
    "total": 3,
    "max_score": null,
    "hits": [
      {
        "_index": "table",
        "_score": null,
        "sort": [
          0
        ]
      },
      {
        "_index": "table",
        "_score": null,
        "fields": {
          "k1": [
            "kkk1"
          ]
        },
        "sort": [
          0
        ]
      },
      {
        "_index": "table",
        "_score": null,
        "sort": [
          0
        ]
      }
    ]
  }
}
```

But in Doris on ES,Be fetched data parallelly on all shards, and use `filter_path` to reduce the network cost. The process will be as follows:
```
GET table/_doc/_search?preference=_shards:1&filter_path=_scroll_id,hits.hits._source,hits.total,_id,hits.hits._source.fields,hits.hits.fields
{"query":{"match_all":{}},"stored_fields":"_none_","docvalue_fields":["k1"],"sort":["_doc"],"size":100}

{
  "hits": {
    "total": 0
  }
}

GET table/_doc/_search?preference=_shards:2&filter_path=_scroll_id,hits.hits._source,hits.total,_id,hits.hits._source.fields,hits.hits.fields
{"query":{"match_all":{}},"stored_fields":"_none_","docvalue_fields":["k1"],"sort":["_doc"],"size":100}
{
  "hits": {
    "total": 1
  }
}

GET table/_doc/_search?preference=_shards:3&filter_path=_scroll_id,hits.hits._source,hits.total,_id,hits.hits._source.fields,hits.hits.fields
{"query":{"match_all":{}},"stored_fields":"_none_","docvalue_fields":["k1"],"sort":["_doc"],"size":100}
{
  "hits": {
    "total": 1,
    "hits": [
      {
        "fields": {
          "k1": [
            "kkk1"
          ]
        }
      }
    ]
  }
}
```
*Scan-Worker On BE which processed result of shard2  will failed.* 

**The reasons are as follows:**
1. "filter_path" causes the hits.hits object not exist.  
2. In the current implementation, if there are some data rows(total > 0), the hits.hits. object must be an array

**How To Fix it**

Two Method:
1. modify "filter_path" to contain the hits.  
Pros: Fixed Code is very simple
Cons: More network cost
2. Deal with the case where fields are missing in a batch. 
Pros: No loss of performance
Cons: Code is more complex 

Performance first, I use Method2.

**Design**
1. Add a variable "_doc_value_mode" into Class "EsScrollParser" to =indicate whether the data processed by this parser is doc_value_mode or not.
2. "_doc_value_mode" is passed from ESScollReader <- ESScanner <- ScrollQueryBuilder::build() that determines whether DSL is enable doc_value_mode
3. When hits.hits of response from ES is empty and total > 0. We know there are data lines, but the corresponding fields do not exist. EsScrollParser will use "_doc_value_mode"  and _total to construct _total lines which fields are assigned with 'NULL'
2020-05-11 15:34:12 +08:00

523 lines
19 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.
#include "exec/es/es_scroll_parser.h"
#include <boost/algorithm/string.hpp>
#include <gutil/strings/substitute.h>
#include <string>
#include "common/logging.h"
#include "common/status.h"
#include "runtime/mem_pool.h"
#include "runtime/mem_tracker.h"
#include "rapidjson/rapidjson.h"
#include "rapidjson/document.h"
#include "rapidjson/stringbuffer.h"
#include "rapidjson/writer.h"
#include "util/string_parser.hpp"
namespace doris {
static const char* FIELD_SCROLL_ID = "_scroll_id";
static const char* FIELD_HITS = "hits";
static const char* FIELD_INNER_HITS = "hits";
static const char* FIELD_SOURCE = "_source";
static const char* FIELD_TOTAL = "total";
// get the original json data type
std::string json_type_to_string(rapidjson::Type type) {
switch (type) {
case rapidjson::kNumberType:
return "Number";
case rapidjson::kStringType:
return "Varchar/Char";
case rapidjson::kArrayType:
return "Array";
case rapidjson::kObjectType:
return "Object";
case rapidjson::kNullType:
return "Null Type";
case rapidjson::kFalseType:
case rapidjson::kTrueType:
return "True/False";
default:
return "Unknown Type";
}
}
// transfer rapidjson::Value to string representation
std::string json_value_to_string(const rapidjson::Value& value) {
rapidjson::StringBuffer scratch_buffer;
rapidjson::Writer<rapidjson::StringBuffer> temp_writer(scratch_buffer);
value.Accept(temp_writer);
return scratch_buffer.GetString();
}
static const string ERROR_INVALID_COL_DATA = "Data source returned inconsistent column data. "
"Expected value of type $0 based on column metadata. This likely indicates a "
"problem with the data source library.";
static const string ERROR_MEM_LIMIT_EXCEEDED = "DataSourceScanNode::$0() failed to allocate "
"$1 bytes for $2.";
static const string ERROR_COL_DATA_IS_ARRAY = "Data source returned an array for the type $0"
"based on column metadata.";
#define RETURN_ERROR_IF_COL_IS_ARRAY(col, type) \
do { \
if (col.IsArray()) { \
std::stringstream ss; \
ss << "Expected value of type: " \
<< type_to_string(type) \
<< "; but found type: " << json_type_to_string(col.GetType()) \
<< "; Docuemnt slice is : " << json_value_to_string(col); \
return Status::RuntimeError(ss.str()); \
} \
} while (false)
#define RETURN_ERROR_IF_COL_IS_NOT_STRING(col, type) \
do { \
if (!col.IsString()) { \
std::stringstream ss; \
ss << "Expected value of type: " \
<< type_to_string(type) \
<< "; but found type: " << json_type_to_string(col.GetType()) \
<< "; Docuemnt source slice is : " << json_value_to_string(col); \
return Status::RuntimeError(ss.str()); \
} \
} while (false)
#define RETURN_ERROR_IF_COL_IS_NOT_NUMBER(col, type) \
do { \
if (!col.IsNumber()) { \
std::stringstream ss; \
ss << "Expected value of type: " \
<< type_to_string(type) \
<< "; but found type: " <<json_type_to_string(col.GetType()) \
<< "; Document value is: " << json_value_to_string(col); \
return Status::RuntimeError(ss.str()); \
} \
} while (false)
#define RETURN_ERROR_IF_PARSING_FAILED(result, col, type) \
do { \
if (result != StringParser::PARSE_SUCCESS) { \
std::stringstream ss; \
ss << "Expected value of type: " \
<< type_to_string(type) \
<< "; but found type: " << json_type_to_string(col.GetType()) \
<< "; Docuemnt source slice is : " << json_value_to_string(col); \
return Status::RuntimeError(ss.str()); \
} \
} while (false)
#define RETURN_ERROR_IF_CAST_FORMAT_ERROR(col, type) \
do { \
std::stringstream ss; \
ss << "Expected value of type: " \
<< type_to_string(type) \
<< "; but found type: " << json_type_to_string(col.GetType()) \
<< "; Docuemnt slice is : " << json_value_to_string(col); \
return Status::RuntimeError(ss.str()); \
} while (false)
template <typename T>
static Status get_int_value(const rapidjson::Value &col, PrimitiveType type, void* slot, bool pure_doc_value) {
if (col.IsNumber()) {
*reinterpret_cast<T*>(slot) = (T)(sizeof(T) < 8 ? col.GetInt() : col.GetInt64());
return Status::OK();
}
if (pure_doc_value && col.IsArray()) {
RETURN_ERROR_IF_COL_IS_NOT_NUMBER(col[0], type);
*reinterpret_cast<T*>(slot) = (T)(sizeof(T) < 8 ? col[0].GetInt() : col[0].GetInt64());
return Status::OK();
}
RETURN_ERROR_IF_COL_IS_ARRAY(col, type);
RETURN_ERROR_IF_COL_IS_NOT_STRING(col, type);
StringParser::ParseResult result;
const std::string& val = col.GetString();
size_t len = col.GetStringLength();
T v = StringParser::string_to_int<T>(val.c_str(), len, &result);
RETURN_ERROR_IF_PARSING_FAILED(result, col, type);
if (sizeof(T) < 16) {
*reinterpret_cast<T*>(slot) = v;
} else {
DCHECK(sizeof(T) == 16);
memcpy(slot, &v, sizeof(v));
}
return Status::OK();
}
template <typename T>
static Status get_float_value(const rapidjson::Value &col, PrimitiveType type, void* slot, bool pure_doc_value) {
DCHECK(sizeof(T) == 4 || sizeof(T) == 8);
if (col.IsNumber()) {
*reinterpret_cast<T*>(slot) = (T)(sizeof(T) == 4 ? col.GetFloat() : col.GetDouble());
return Status::OK();
}
if (pure_doc_value && col.IsArray()) {
*reinterpret_cast<T*>(slot) = (T)(sizeof(T) == 4 ? col[0].GetFloat() : col[0].GetDouble());
return Status::OK();
}
RETURN_ERROR_IF_COL_IS_ARRAY(col, type);
RETURN_ERROR_IF_COL_IS_NOT_STRING(col, type);
StringParser::ParseResult result;
const std::string& val = col.GetString();
size_t len = col.GetStringLength();
T v = StringParser::string_to_float<T>(val.c_str(), len, &result);
RETURN_ERROR_IF_PARSING_FAILED(result, col, type);
*reinterpret_cast<T*>(slot) = v;
return Status::OK();
}
ScrollParser::ScrollParser(bool doc_value_mode) :
_scroll_id(""),
_total(0),
_size(0),
_line_index(0),
_doc_value_mode(doc_value_mode) {
}
ScrollParser::~ScrollParser() {
}
Status ScrollParser::parse(const std::string& scroll_result, bool exactly_once) {
_document_node.Parse(scroll_result.c_str());
if (_document_node.HasParseError()) {
std::stringstream ss;
ss << "Parsing json error, json is: " << scroll_result;
return Status::InternalError(ss.str());
}
if (!exactly_once && !_document_node.HasMember(FIELD_SCROLL_ID)) {
LOG(WARNING) << "Document has not a scroll id field scroll reponse:" << scroll_result;
return Status::InternalError("Document has not a scroll id field");
}
if (!exactly_once) {
const rapidjson::Value &scroll_node = _document_node[FIELD_SCROLL_ID];
_scroll_id = scroll_node.GetString();
}
// { hits: { total : 2, "hits" : [ {}, {}, {} ]}}
const rapidjson::Value &outer_hits_node = _document_node[FIELD_HITS];
const rapidjson::Value &field_total = outer_hits_node[FIELD_TOTAL];
// after es 7.x "total": { "value": 1, "relation": "eq" }
if (field_total.IsObject()) {
const rapidjson::Value &field_relation_value = field_total["relation"];
std::string relation = field_relation_value.GetString();
// maybe not happend on scoll sort mode, for logically rigorous
if ("eq" != relation) {
return Status::InternalError("Could not identify exact hit count for search response");
}
const rapidjson::Value &field_total_value = field_total["value"];
_total = field_total_value.GetInt();
} else {
_total = field_total.GetInt();
}
if (_total == 0) {
return Status::OK();
}
VLOG(1) << "es_scan_reader parse scroll result: " << scroll_result;
if (!outer_hits_node.HasMember(FIELD_INNER_HITS)) {
// this is caused by query some columns which are not exit, e.g.
// A Index has fields: k1,k2,k3. and we put some rows into this Index (some fields dose NOT contain any data)
// e.g.
// put index/_doc/1 {"k2":"123"}
// put index/_doc/2 {"k3":"123}
// then we use sql `select k1 from table`
// what ES return is like this: {hits: {total:2}
return Status::OK();
}
const rapidjson::Value &inner_hits_node = outer_hits_node[FIELD_INNER_HITS];
if (!inner_hits_node.IsArray()) {
LOG(WARNING) << "exception maybe happend on es cluster, reponse:" << scroll_result;
return Status::InternalError("inner hits node is not an array");
}
rapidjson::Document::AllocatorType& a = _document_node.GetAllocator();
_inner_hits_node.CopyFrom(inner_hits_node, a);
_size = _inner_hits_node.Size();
return Status::OK();
}
int ScrollParser::get_size() {
return _size;
}
const std::string& ScrollParser::get_scroll_id() {
return _scroll_id;
}
int ScrollParser::get_total() {
return _total;
}
Status ScrollParser::fill_tuple(const TupleDescriptor* tuple_desc,
Tuple* tuple, MemPool* tuple_pool, bool* line_eof, const std::map<std::string, std::string>& docvalue_context) {
*line_eof = true;
if (_size <= 0 || _line_index >= _size) {
// _source is fetched from ES
if (!_doc_value_mode) {
return Status::OK();
}
// _fields(doc_value) is fetched from ES
if (_total <= 0 || _line_index >= _total) {
return Status::OK();
}
// here is operations for `enable_doc_value_scan`.
// This indicates that the fields does not exist(e.g. never assign values to these fields), but other fields have values.
// so, number of rows is >= 0, we need fill `NULL` to these fields that does not exist.
_line_index++;
tuple->init(tuple_desc->byte_size());
for (int i = 0; i < tuple_desc->slots().size(); ++i) {
const SlotDescriptor* slot_desc = tuple_desc->slots()[i];
if (slot_desc->is_materialized()) {
tuple->set_null(slot_desc->null_indicator_offset());
}
}
*line_eof = false;
return Status::OK();
}
const rapidjson::Value& obj = _inner_hits_node[_line_index++];
bool pure_doc_value = false;
if (obj.HasMember("fields")) {
pure_doc_value = true;
}
const rapidjson::Value& line = obj.HasMember(FIELD_SOURCE) ? obj[FIELD_SOURCE] : obj["fields"];
tuple->init(tuple_desc->byte_size());
for (int i = 0; i < tuple_desc->slots().size(); ++i) {
const SlotDescriptor* slot_desc = tuple_desc->slots()[i];
if (!slot_desc->is_materialized()) {
continue;
}
// if pure_doc_value enabled, docvalue_context must contains the key
// todo: need move all `pure_docvalue` for every tuple outside fill_tuple
// should check pure_docvalue for one table scan not every tuple
const char* col_name = pure_doc_value ? docvalue_context.at(slot_desc->col_name()).c_str() : slot_desc->col_name().c_str();
rapidjson::Value::ConstMemberIterator itr = line.FindMember(col_name);
if (itr == line.MemberEnd()) {
tuple->set_null(slot_desc->null_indicator_offset());
continue;
}
tuple->set_not_null(slot_desc->null_indicator_offset());
const rapidjson::Value &col = line[col_name];
void* slot = tuple->get_slot(slot_desc->tuple_offset());
PrimitiveType type = slot_desc->type().type;
switch (type) {
case TYPE_CHAR:
case TYPE_VARCHAR: {
// sometimes elasticsearch user post some not-string value to Elasticsearch Index.
// because of reading value from _source, we can not process all json type and then just transfer the value to original string representation
// this may be a tricky, but we can workaround this issue
std::string val;
if (pure_doc_value) {
if (!col[0].IsString()) {
val = json_value_to_string(col[0]);
} else {
val = col[0].GetString();
}
} else {
RETURN_ERROR_IF_COL_IS_ARRAY(col, type);
if (!col.IsString()) {
val = json_value_to_string(col);
} else {
val = col.GetString();
}
}
size_t val_size = val.length();
char* buffer = reinterpret_cast<char*>(tuple_pool->try_allocate_unaligned(val_size));
if (UNLIKELY(buffer == NULL)) {
string details = strings::Substitute(ERROR_MEM_LIMIT_EXCEEDED, "MaterializeNextRow",
val_size, "string slot");
return tuple_pool->mem_tracker()->MemLimitExceeded(NULL, details, val_size);
}
memcpy(buffer, val.data(), val_size);
reinterpret_cast<StringValue*>(slot)->ptr = buffer;
reinterpret_cast<StringValue*>(slot)->len = val_size;
break;
}
case TYPE_TINYINT: {
Status status = get_int_value<int8_t>(col, type, slot, pure_doc_value);
if (!status.ok()) {
return status;
}
break;
}
case TYPE_SMALLINT: {
Status status = get_int_value<int16_t>(col, type, slot, pure_doc_value);
if (!status.ok()) {
return status;
}
break;
}
case TYPE_INT: {
Status status = get_int_value<int32_t>(col, type, slot, pure_doc_value);
if (!status.ok()) {
return status;
}
break;
}
case TYPE_BIGINT: {
Status status = get_int_value<int64_t>(col, type, slot, pure_doc_value);
if (!status.ok()) {
return status;
}
break;
}
case TYPE_LARGEINT: {
Status status = get_int_value<__int128>(col, type, slot, pure_doc_value);
if (!status.ok()) {
return status;
}
break;
}
case TYPE_DOUBLE: {
Status status = get_float_value<double>(col, type, slot, pure_doc_value);
if (!status.ok()) {
return status;
}
break;
}
case TYPE_FLOAT: {
Status status = get_float_value<float>(col, type, slot, pure_doc_value);
if (!status.ok()) {
return status;
}
break;
}
case TYPE_BOOLEAN: {
if (col.IsBool()) {
*reinterpret_cast<int8_t*>(slot) = col.GetBool();
break;
}
if (col.IsNumber()) {
*reinterpret_cast<int8_t*>(slot) = col.GetInt();
break;
}
if (pure_doc_value && col.IsArray()) {
*reinterpret_cast<int8_t*>(slot) = col[0].GetBool();
break;
}
RETURN_ERROR_IF_COL_IS_ARRAY(col, type);
RETURN_ERROR_IF_COL_IS_NOT_STRING(col, type);
const std::string& val = col.GetString();
size_t val_size = col.GetStringLength();
StringParser::ParseResult result;
bool b =
StringParser::string_to_bool(val.c_str(), val_size, &result);
RETURN_ERROR_IF_PARSING_FAILED(result, col, type);
*reinterpret_cast<int8_t*>(slot) = b;
break;
}
case TYPE_DATE:
case TYPE_DATETIME: {
if (col.IsNumber()) {
if (!reinterpret_cast<DateTimeValue*>(slot)->from_unixtime(col.GetInt64(), "+08:00")) {
RETURN_ERROR_IF_CAST_FORMAT_ERROR(col, type);
}
if (type == TYPE_DATE) {
reinterpret_cast<DateTimeValue*>(slot)->cast_to_date();
} else {
reinterpret_cast<DateTimeValue*>(slot)->set_type(TIME_DATETIME);
}
break;
}
if (pure_doc_value && col.IsArray()) {
if (!reinterpret_cast<DateTimeValue*>(slot)->from_unixtime(col[0].GetInt64(), "+08:00")) {
RETURN_ERROR_IF_CAST_FORMAT_ERROR(col, type);
}
if (type == TYPE_DATE) {
reinterpret_cast<DateTimeValue*>(slot)->cast_to_date();
} else {
reinterpret_cast<DateTimeValue*>(slot)->set_type(TIME_DATETIME);
}
break;
}
RETURN_ERROR_IF_COL_IS_ARRAY(col, type);
RETURN_ERROR_IF_COL_IS_NOT_STRING(col, type);
DateTimeValue* ts_slot = reinterpret_cast<DateTimeValue*>(slot);
const std::string& val = col.GetString();
size_t val_size = col.GetStringLength();
if (!ts_slot->from_date_str(val.c_str(), val_size)) {
RETURN_ERROR_IF_CAST_FORMAT_ERROR(col, type);
}
if (type == TYPE_DATE) {
ts_slot->cast_to_date();
} else {
ts_slot->to_datetime();
}
break;
}
default: {
DCHECK(false);
break;
}
}
}
*line_eof = false;
return Status::OK();
}
}