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#pragma once
#include <Core/Block.h>
#include <Interpreters/Context.h>
#include <Dictionaries/IDictionarySource.h>
#include <Dictionaries/DictionaryStructure.h>
#include <Processors/Sources/ShellCommandSource.h>
namespace DB
{
/** ExecutablePoolDictionarySource allows loading data from pool of processes.
* When client requests ids or keys source get process from ProcessPool
* and create stream based on source format from process stdout.
* It is important that stream format will expect only rows that were requested.
* When stream is finished process is returned back to the ProcessPool.
* If there are no processes in pool during request client will be blocked
* until some process will be returned to pool.
*/
class ExecutablePoolDictionarySource final : public IDictionarySource
{
public:
struct Configuration
{
String command;
std::vector<String> command_arguments;
bool implicit_key;
};
ExecutablePoolDictionarySource(
const DictionaryStructure & dict_struct_,
const Configuration & configuration_,
Block & sample_block_,
std::shared_ptr<ShellCommandSourceCoordinator> coordinator_,
ContextPtr context_);
ExecutablePoolDictionarySource(const ExecutablePoolDictionarySource & other);
ExecutablePoolDictionarySource & operator=(const ExecutablePoolDictionarySource &) = delete;
QueryPipeline loadAll() override;
/** The logic of this method is flawed, absolutely incorrect and ignorant.
* It may lead to skipping some values due to clock sync or timezone changes.
* The intended usage of "update_field" is totally different.
*/
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;
bool hasUpdateField() const override;
DictionarySourcePtr clone() const override;
std::string toString() const override;
QueryPipeline getStreamForBlock(const Block & block);
private:
const DictionaryStructure dict_struct;
const Configuration configuration;
Block sample_block;
std::shared_ptr<ShellCommandSourceCoordinator> coordinator;
ContextPtr context;
Poco::Logger * log;
};
}
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