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// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#pragma once
#include "sessionid.h"
#include <vespa/searchlib/attribute/iattributemanager.h>
#include <vespa/vespalib/util/time.h>
#include <vector>
#include <map>
namespace search::aggregation { class Grouping; }
namespace search::grouping {
class GroupingContext;
class GroupingManager;
/**
* A grouping session represents the execution of a grouping expression with one
* or more passes. Multiple passes are supported by keeping internal state, and
* providing a way to copy parts of this state into a context object for each
* pass.
**/
class GroupingSession
{
private:
using GroupingPtr = std::shared_ptr<aggregation::Grouping>;
using GroupingMap = std::map<uint32_t, GroupingPtr>;
using GroupingList = std::vector<GroupingPtr>;
SessionId _sessionId;
std::unique_ptr<GroupingContext> _mgrContext;
std::unique_ptr<GroupingManager> _groupingManager;
GroupingMap _groupingMap;
vespalib::steady_time _timeOfDoom;
public:
using UP = std::unique_ptr<GroupingSession>;
/**
* Create a new grouping session
*
* @param sessionId The session id of this session.
* @param groupingContext grouping context.
* @param attrCtx attribute context.
**/
GroupingSession(const SessionId & sessionId,
GroupingContext & groupingContext,
const attribute::IAttributeContext &attrCtx);
GroupingSession(const GroupingSession &) = delete;
GroupingSession &operator=(const GroupingSession &) = delete;
/**
* Release resources
**/
~GroupingSession();
/**
* Return our session identifier
**/
const SessionId & getSessionId() const { return _sessionId; }
/**
* Initialize the session with data from the current context.
* @param groupingContext The current grouping context.
* @param attrCtx attribute context.
**/
void init(GroupingContext & groupingContext, const attribute::IAttributeContext &attrCtx);
/**
* This function is called to prepare for creation of individual
* contexts for separate threads.
*
* @param num_threads number of threads that will request contexts
**/
void prepareThreadContextCreation(size_t num_threads);
/**
* Create a grouping context to be used by a single thread when
* performing multi-threaded grouping. Thread 0 will get a
* grouping context that shares groups with this session while
* other threads will get equivalent copies that can later be
* merged into the master context after partial grouping is
* performed in parallel. Note that this thread may be called by
* multiple threads at the same time.
*
* @param thread_id thread id
* @param attrCtx attribute context.
**/
std::unique_ptr<GroupingContext> createThreadContext(size_t thread_id, const attribute::IAttributeContext &attrCtx);
/**
* Return the GroupingManager to use when performing grouping.
**/
GroupingManager & getGroupingManager() { return *_groupingManager; }
/**
* Continue excuting a query given a context.
*
* @param context The grouping context which contains information about the
* current pass.
**/
void continueExecution(GroupingContext & context);
/**
* Checks whether or not the session is finished.
**/
bool finished() const { return _groupingMap.empty(); }
/**
* Get this sessions timeout.
*/
vespalib::steady_time getTimeOfDoom() const { return _timeOfDoom; }
};
}
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