ClickHouse/src/Dictionaries/ClickHouseDictionarySource.h
2022-08-03 15:44:08 -04:00

92 lines
2.9 KiB
C++

#pragma once
#include <memory>
#include <Poco/Logger.h>
#include <Client/ConnectionPoolWithFailover.h>
#include <Interpreters/Context.h>
#include "DictionaryStructure.h"
#include "ExternalQueryBuilder.h"
#include "IDictionarySource.h"
namespace DB
{
/** Allows loading dictionaries from local or remote ClickHouse instance
* @todo use ConnectionPoolWithFailover
* @todo invent a way to keep track of source modifications
*/
class ClickHouseDictionarySource final : public IDictionarySource
{
public:
struct Configuration
{
const std::string host;
const std::string user;
const std::string password;
const std::string quota_key;
const std::string db;
const std::string table;
const std::string query;
const std::string where;
const std::string invalidate_query;
const std::string update_field;
const UInt64 update_lag;
const UInt16 port;
const bool is_local;
const bool secure;
};
ClickHouseDictionarySource(
const DictionaryStructure & dict_struct_,
const Configuration & configuration_,
const Block & sample_block_,
ContextMutablePtr context_);
/// copy-constructor is provided in order to support cloneability
ClickHouseDictionarySource(const ClickHouseDictionarySource & other);
ClickHouseDictionarySource & operator=(const ClickHouseDictionarySource &) = delete;
QueryPipeline loadAllWithSizeHint(std::atomic<size_t> * result_size_hint) override;
QueryPipeline loadAll() override;
QueryPipeline loadUpdatedAll() override;
QueryPipeline loadIds(const std::vector<UInt64> & ids) override;
QueryPipeline loadKeys(const Columns & key_columns, const std::vector<size_t> & requested_rows) override;
bool isModified() const override;
bool supportsSelectiveLoad() const override { return true; }
bool hasUpdateField() const override;
DictionarySourcePtr clone() const override { return std::make_shared<ClickHouseDictionarySource>(*this); }
std::string toString() const override;
/// Used for detection whether the hashtable should be preallocated
/// (since if there is WHERE then it can filter out too much)
bool hasWhere() const { return !configuration.where.empty(); }
private:
std::string getUpdateFieldAndDate();
QueryPipeline createStreamForQuery(const String & query, std::atomic<size_t> * result_size_hint = nullptr);
std::string doInvalidateQuery(const std::string & request) const;
std::chrono::time_point<std::chrono::system_clock> update_time;
const DictionaryStructure dict_struct;
const Configuration configuration;
mutable std::string invalidate_query_response;
ExternalQueryBuilder query_builder;
Block sample_block;
ContextMutablePtr context;
ConnectionPoolWithFailoverPtr pool;
const std::string load_all_query;
Poco::Logger * log = &Poco::Logger::get("ClickHouseDictionarySource");
};
}