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
|
// wiredtiger_session_cache.h
/**
* Copyright (C) 2014 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 <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 <map>
#include <string>
#include <vector>
#include <boost/thread/mutex.hpp>
#include <boost/thread/shared_mutex.hpp>
#include <wiredtiger.h>
#include "mongo/platform/atomic_word.h"
namespace mongo {
class WiredTigerKVEngine;
/**
* This is a structure that caches 1 cursor for each uri.
* The idea is that there is a pool of these somewhere.
* NOT THREADSAFE
*/
class WiredTigerSession {
public:
WiredTigerSession( WT_CONNECTION* conn, int epoch );
~WiredTigerSession();
WT_SESSION* getSession() const { return _session; }
WT_CURSOR* getCursor(const std::string& uri, uint64_t id);
void releaseCursor(uint64_t id, WT_CURSOR *cursor);
void closeAllCursors();
int cursorsOut() const { return _cursorsOut; }
int epoch() const { return _epoch; }
static uint64_t genCursorId();
/**
* For "metadata:" cursors. Guaranteed never to collide with genCursorId() ids.
*/
static const uint64_t kMetadataCursorId = 0;
private:
int _epoch;
WT_SESSION* _session; // owned
typedef std::vector<WT_CURSOR*> Cursors;
typedef std::map<uint64_t, Cursors> CursorMap;
CursorMap _curmap; // owned
int _cursorsOut;
};
class WiredTigerSessionCache {
public:
WiredTigerSessionCache( WiredTigerKVEngine* engine );
WiredTigerSessionCache( WT_CONNECTION* conn );
~WiredTigerSessionCache();
WiredTigerSession* getSession();
void releaseSession( WiredTigerSession* session );
void closeAll();
void shuttingDown();
private:
typedef std::vector<WiredTigerSession*> SessionPool;
bool _shouldBeClosed( WiredTigerSession* session ) const;
WiredTigerKVEngine* _engine; // not owned, might be NULL
WT_CONNECTION* _conn; // not owned
// Session pool and protection around the get/return/cleanup methods
mutable boost::mutex _sessionLock;
SessionPool _sessionPool;
bool _inShutdown;
};
}
|
