1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
|
/* Copyright 2009 10gen 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 <http://www.gnu.org/licenses/>.
*
* 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 <set>
#include <string>
#include "mongo/client/query.h"
#include "mongo/client/query_spec.h"
#include "mongo/db/namespace_string.h"
#include "mongo/s/client/shard.h"
#include "mongo/s/stale_exception.h"
namespace mongo {
class ChunkManager;
class DBClientCursor;
class DBClientCursorHolder;
class OperationContext;
struct ParallelConnectionMetadata;
struct ParallelConnectionState;
struct CommandInfo {
CommandInfo() = default;
CommandInfo(const std::string& vns, const BSONObj& filter, const BSONObj& collation)
: versionedNS(vns), cmdFilter(filter), cmdCollation(collation) {}
bool isEmpty() const {
return versionedNS.empty();
}
std::string toString() const {
return str::stream() << "CInfo "
<< BSON("v_ns" << versionedNS << "filter" << cmdFilter << "collation"
<< cmdCollation);
}
std::string versionedNS;
BSONObj cmdFilter;
BSONObj cmdCollation;
};
/**
* Runs a query in parallel across N servers, enforcing compatible chunk versions for queries
* across all shards.
*
* If CommandInfo is provided, the ParallelCursor does not use the direct .$cmd namespace in the
* query spec, but instead enforces versions across another namespace specified by CommandInfo.
* This is to support commands like:
* db.runCommand({ fileMD5 : "<coll name>" })
*
* There is a deprecated legacy mode as well which effectively does a merge-sort across a number
* of servers, but does not correctly enforce versioning (used only in mapreduce).
*/
class ParallelSortClusteredCursor {
public:
ParallelSortClusteredCursor(const QuerySpec& qSpec, const CommandInfo& cInfo);
// DEPRECATED legacy constructor for pure mergesort functionality - do not use
ParallelSortClusteredCursor(const std::set<std::string>& servers,
const std::string& ns,
const Query& q,
int options = 0,
const BSONObj& fields = BSONObj());
~ParallelSortClusteredCursor();
void init(OperationContext* opCtx);
bool more();
BSONObj next();
/**
* Returns the set of shards with open cursors.
*/
void getQueryShardIds(std::set<ShardId>& shardIds) const;
std::shared_ptr<DBClientCursor> getShardCursor(const ShardId& shardId) const;
private:
using ShardCursorsMap = std::map<ShardId, ParallelConnectionMetadata>;
void fullInit(OperationContext* opCtx);
void startInit(OperationContext* opCtx);
void finishInit(OperationContext* opCtx);
bool isCommand() {
return NamespaceString(_qSpec.ns()).isCommand();
}
void _finishCons();
void _markStaleNS(const NamespaceString& staleNS, const StaleConfigException& e);
bool _didInit;
bool _done;
QuerySpec _qSpec;
CommandInfo _cInfo;
// Count round-trips req'd for namespaces and total
std::map<std::string, int> _staleNSMap;
int _totalTries;
ShardCursorsMap _cursorMap;
// LEGACY BELOW
int _numServers;
int _lastFrom;
std::set<std::string> _servers;
BSONObj _sortKey;
DBClientCursorHolder* _cursors;
int _needToSkip;
/**
* Setups the shard version of the connection. When using a replica
* set connection and the primary cannot be reached, the version
* will not be set if the slaveOk flag is set.
*/
void setupVersionAndHandleSlaveOk(OperationContext* opCtx,
std::shared_ptr<ParallelConnectionState> state /* in & out */,
const ShardId& shardId,
std::shared_ptr<Shard> primary /* in */,
const NamespaceString& ns,
const std::string& vinfo,
std::shared_ptr<ChunkManager> manager /* in */);
// LEGACY init - Needed for map reduce
void _oldInit();
// LEGACY - Needed ONLY for _oldInit
std::string _ns;
BSONObj _query;
int _options;
BSONObj _fields;
int _batchSize;
};
/**
* Throws a StaleConfigException wrapping the stale error document in this cursor when the
* ShardConfigStale flag is set or a command returns a ErrorCodes::StaleConfig error code.
*/
void throwCursorStale(DBClientCursor* cursor);
} // namespace mongo
|
