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
|
/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1996, 1997
* Sleepycat Software. All rights reserved.
*
* @(#)txn.h 10.11 (Sleepycat) 10/25/97
*/
#ifndef _TXN_H_
#define _TXN_H_
/*
* The name of the transaction shared memory region is DEFAULT_TXN_FILE and
* the region is always created group RW of the group owning the directory.
*/
#define DEFAULT_TXN_FILE "__db_txn.share"
/* TXN_MINIMUM = (DB_LOCK_MAXID + 1) but this makes compilers complain. */
#define TXN_MINIMUM 0x80000000
#define TXN_INVALID 0xffffffff /* Maximum number of txn ids. */
/*
* Transaction type declarations.
*/
/*
* Internal data maintained in shared memory for each transaction.
*/
typedef struct __txn_detail {
u_int32_t txnid; /* current transaction id
used to link free list also */
DB_LSN last_lsn; /* last lsn written for this txn */
DB_LSN begin_lsn; /* lsn of begin record */
size_t last_lock; /* offset in lock region of last lock
for this transaction. */
#define TXN_UNALLOC 0
#define TXN_RUNNING 1
#define TXN_ABORTED 2
#define TXN_PREPARED 3
u_int32_t status; /* status of the transaction */
SH_TAILQ_ENTRY links; /* free/active list */
} TXN_DETAIL;
/*
* The transaction manager encapsulates the transaction system. It contains
* references to the log and lock managers as well as the state that keeps
* track of the shared memory region.
*/
struct __db_txnmgr {
/* These fields need to be protected for multi-threaded support. */
db_mutex_t *mutexp; /* Synchronization. */
/* list of active transactions */
TAILQ_HEAD(_chain, __db_txn) txn_chain;
/* These fields are not protected. */
DB_ENV *dbenv; /* Environment. */
int (*recover) /* Recovery dispatch routine */
__P((DB_LOG *, DBT *, DB_LSN *, int, void *));
int fd; /* mapped file descriptor */
u_int flags; /* DB_TXN_NOSYNC, DB_THREAD */
size_t reg_size; /* how large we think the region is */
DB_TXNREGION *region; /* address of shared memory region */
void *mem; /* address of the shalloc space */
};
/*
* Layout of the shared memory region.
* The region consists of a DB_TXNREGION structure followed by a large
* pool of shalloc'd memory which is used to hold TXN_DETAIL structures
* and thread mutexes (which are dynamically allocated).
*/
struct __db_txnregion {
RLAYOUT hdr; /* Shared memory region header. */
u_int32_t magic; /* transaction magic number */
u_int32_t version; /* version number */
u_int32_t maxtxns; /* maximum number of active txns */
u_int32_t last_txnid; /* last transaction id given out */
DB_LSN pending_ckp; /* last checkpoint did not finish */
DB_LSN last_ckp; /* lsn of the last checkpoint */
time_t time_ckp; /* time of last checkpoint */
u_int32_t logtype; /* type of logging */
u_int32_t locktype; /* lock type */
u_int32_t naborts; /* number of aborted transactions */
u_int32_t ncommits; /* number of committed transactions */
u_int32_t nbegins; /* number of begun transactions */
SH_TAILQ_HEAD(_active) active_txn; /* active transaction list */
};
/*
* Make the region large enough to hold N transaction detail structures
* plus some space to hold thread handles and the beginning of the shalloc
* region.
*/
#define TXN_REGION_SIZE(N) \
(sizeof(DB_TXNREGION) + N * sizeof(TXN_DETAIL) + 1000)
/* Macros to lock/unlock the region and threads. */
#define LOCK_TXNTHREAD(tmgrp) \
if (F_ISSET(tmgrp, DB_THREAD)) \
(void)__db_mutex_lock((tmgrp)->mutexp, -1)
#define UNLOCK_TXNTHREAD(tmgrp) \
if (F_ISSET(tmgrp, DB_THREAD)) \
(void)__db_mutex_unlock((tmgrp)->mutexp, -1)
#define LOCK_TXNREGION(tmgrp) \
(void)__db_mutex_lock(&(tmgrp)->region->hdr.lock, (tmgrp)->fd)
#define UNLOCK_TXNREGION(tmgrp) \
(void)__db_mutex_unlock(&(tmgrp)->region->hdr.lock, (tmgrp)->fd)
/*
* Log record types.
*/
#define TXN_BEGIN 1
#define TXN_COMMIT 2
#define TXN_PREPARE 3
#define TXN_CHECKPOINT 4
#include "txn_auto.h"
#include "txn_ext.h"
#endif /* !_TXN_H_ */
|
