/**
* Copyright (C) 2015 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see .
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#pragma once
#include
#include "mongo/bson/bsonobj.h"
#include "mongo/db/cursor_id.h"
#include "mongo/db/query/cursor_response.h"
#include "mongo/db/query/explain_options.h"
namespace mongo {
template
class StatusWith;
class CanonicalQuery;
class OperationContext;
struct GetMoreRequest;
struct ReadPreferenceSetting;
/**
* Methods for running find and getMore operations across a sharded cluster.
*/
class ClusterFind {
public:
// The number of times we are willing to re-target and re-run the query after receiving a stale
// config, snapshot, or shard not found error.
static const size_t kMaxRetries;
/**
* Runs query 'query', targeting remote hosts according to the read preference in 'readPref'.
*
* On success, fills out 'results' with the first batch of query results and returns the cursor
* id which the caller can use on subsequent getMore operations. If no cursor needed to be saved
* (e.g. the cursor was exhausted without need for a getMore), returns a cursor id of 0.
*/
static CursorId runQuery(OperationContext* opCtx,
const CanonicalQuery& query,
const ReadPreferenceSetting& readPref,
std::vector* results);
/**
* Executes the getMore request 'request', and on success returns a CursorResponse.
*/
static StatusWith runGetMore(OperationContext* opCtx,
const GetMoreRequest& request);
};
} // namespace mongo