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
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
|
/*-
* Copyright (c) 2014-2015 MongoDB, Inc.
* Copyright (c) 2008-2014 WiredTiger, Inc.
* All rights reserved.
*
* See the file LICENSE for redistribution information.
*/
#include "wt_internal.h"
/*
* __metadata_turtle --
* Return if a key's value should be taken from the turtle file.
*/
static bool
__metadata_turtle(const char *key)
{
switch (key[0]) {
case 'f':
if (strcmp(key, WT_METAFILE_URI) == 0)
return (true);
break;
case 'W':
if (strcmp(key, "WiredTiger version") == 0)
return (true);
if (strcmp(key, "WiredTiger version string") == 0)
return (true);
break;
}
return (false);
}
/*
* __wt_metadata_open --
* Opens the metadata file, sets session->meta_dhandle.
*/
int
__wt_metadata_open(WT_SESSION_IMPL *session)
{
WT_BTREE *btree;
if (session->meta_dhandle != NULL)
return (0);
WT_RET(__wt_session_get_btree(session, WT_METAFILE_URI, NULL, NULL, 0));
session->meta_dhandle = session->dhandle;
WT_ASSERT(session, session->meta_dhandle != NULL);
/*
* Set special flags for the metadata file: eviction (the metadata file
* is in-memory and never evicted), logging (the metadata file is always
* logged if possible).
*
* Test flags before setting them so updates can't race in subsequent
* opens (the first update is safe because it's single-threaded from
* wiredtiger_open).
*/
btree = S2BT(session);
if (!F_ISSET(btree, WT_BTREE_IN_MEMORY))
F_SET(btree, WT_BTREE_IN_MEMORY);
if (!F_ISSET(btree, WT_BTREE_NO_EVICTION))
F_SET(btree, WT_BTREE_NO_EVICTION);
if (F_ISSET(btree, WT_BTREE_NO_LOGGING))
F_CLR(btree, WT_BTREE_NO_LOGGING);
/* The metadata handle doesn't need to stay locked -- release it. */
return (__wt_session_release_btree(session));
}
/*
* __wt_metadata_cursor --
* Opens a cursor on the metadata.
*/
int
__wt_metadata_cursor(
WT_SESSION_IMPL *session, const char *config, WT_CURSOR **cursorp)
{
WT_DATA_HANDLE *saved_dhandle;
WT_DECL_RET;
bool is_dead;
const char *cfg[] =
{ WT_CONFIG_BASE(session, WT_SESSION_open_cursor), config, NULL };
saved_dhandle = session->dhandle;
WT_ERR(__wt_metadata_open(session));
session->dhandle = session->meta_dhandle;
/*
* We use the metadata a lot, so we have a handle cached; lock it and
* increment the in-use counter once the cursor is open.
*/
WT_ERR(__wt_session_lock_dhandle(session, 0, &is_dead));
/* The metadata should never be closed. */
WT_ASSERT(session, !is_dead);
WT_ERR(__wt_curfile_create(session, NULL, cfg, false, false, cursorp));
__wt_cursor_dhandle_incr_use(session);
/* Restore the caller's btree. */
err: session->dhandle = saved_dhandle;
return (ret);
}
/*
* __wt_metadata_insert --
* Insert a row into the metadata.
*/
int
__wt_metadata_insert(
WT_SESSION_IMPL *session, const char *key, const char *value)
{
WT_CURSOR *cursor;
WT_DECL_RET;
WT_RET(__wt_verbose(session, WT_VERB_METADATA,
"Insert: key: %s, value: %s, tracking: %s, %s" "turtle",
key, value, WT_META_TRACKING(session) ? "true" : "false",
__metadata_turtle(key) ? "" : "not "));
if (__metadata_turtle(key))
WT_RET_MSG(session, EINVAL,
"%s: insert not supported on the turtle file", key);
WT_RET(__wt_metadata_cursor(session, NULL, &cursor));
cursor->set_key(cursor, key);
cursor->set_value(cursor, value);
WT_ERR(cursor->insert(cursor));
if (WT_META_TRACKING(session))
WT_ERR(__wt_meta_track_insert(session, key));
err: WT_TRET(cursor->close(cursor));
return (ret);
}
/*
* __wt_metadata_update --
* Update a row in the metadata.
*/
int
__wt_metadata_update(
WT_SESSION_IMPL *session, const char *key, const char *value)
{
WT_CURSOR *cursor;
WT_DECL_RET;
WT_RET(__wt_verbose(session, WT_VERB_METADATA,
"Update: key: %s, value: %s, tracking: %s, %s" "turtle",
key, value, WT_META_TRACKING(session) ? "true" : "false",
__metadata_turtle(key) ? "" : "not "));
if (__metadata_turtle(key))
return (__wt_turtle_update(session, key, value));
if (WT_META_TRACKING(session))
WT_RET(__wt_meta_track_update(session, key));
WT_RET(__wt_metadata_cursor(session, "overwrite", &cursor));
cursor->set_key(cursor, key);
cursor->set_value(cursor, value);
WT_ERR(cursor->insert(cursor));
err: WT_TRET(cursor->close(cursor));
return (ret);
}
/*
* __wt_metadata_remove --
* Remove a row from the metadata.
*/
int
__wt_metadata_remove(WT_SESSION_IMPL *session, const char *key)
{
WT_CURSOR *cursor;
WT_DECL_RET;
WT_RET(__wt_verbose(session, WT_VERB_METADATA,
"Remove: key: %s, tracking: %s, %s" "turtle",
key, WT_META_TRACKING(session) ? "true" : "false",
__metadata_turtle(key) ? "" : "not "));
if (__metadata_turtle(key))
WT_RET_MSG(session, EINVAL,
"%s: remove not supported on the turtle file", key);
WT_RET(__wt_metadata_cursor(session, NULL, &cursor));
cursor->set_key(cursor, key);
WT_ERR(cursor->search(cursor));
if (WT_META_TRACKING(session))
WT_ERR(__wt_meta_track_update(session, key));
WT_ERR(cursor->remove(cursor));
err: WT_TRET(cursor->close(cursor));
return (ret);
}
/*
* __wt_metadata_search --
* Return a copied row from the metadata.
* The caller is responsible for freeing the allocated memory.
*/
int
__wt_metadata_search(
WT_SESSION_IMPL *session, const char *key, char **valuep)
{
WT_CURSOR *cursor;
WT_DECL_RET;
const char *value;
*valuep = NULL;
WT_RET(__wt_verbose(session, WT_VERB_METADATA,
"Search: key: %s, tracking: %s, %s" "turtle",
key, WT_META_TRACKING(session) ? "true" : "false",
__metadata_turtle(key) ? "" : "not "));
if (__metadata_turtle(key))
return (__wt_turtle_read(session, key, valuep));
WT_RET(__wt_metadata_cursor(session, NULL, &cursor));
cursor->set_key(cursor, key);
WT_ERR(cursor->search(cursor));
WT_ERR(cursor->get_value(cursor, &value));
WT_ERR(__wt_strdup(session, value, valuep));
err: WT_TRET(cursor->close(cursor));
return (ret);
}
|
