container_of: don't put member_ptr in container_off.
[ccan] / ccan / tdb / summary.c
1  /* 
2    Trivial Database: human-readable summary code
3    Copyright (C) Rusty Russell 2010
4    
5    This library is free software; you can redistribute it and/or
6    modify it under the terms of the GNU Lesser General Public
7    License as published by the Free Software Foundation; either
8    version 3 of the License, or (at your option) any later version.
9
10    This library is distributed in the hope that it will be useful,
11    but WITHOUT ANY WARRANTY; without even the implied warranty of
12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13    Lesser General Public License for more details.
14
15    You should have received a copy of the GNU Lesser General Public
16    License along with this library; if not, see <http://www.gnu.org/licenses/>.
17 */
18 #include "tdb_private.h"
19
20 #define SUMMARY_FORMAT \
21         "Size of file/data: %u/%zu\n" \
22         "Number of records: %zu\n" \
23         "Smallest/average/largest keys: %zu/%zu/%zu\n" \
24         "Smallest/average/largest data: %zu/%zu/%zu\n" \
25         "Smallest/average/largest padding: %zu/%zu/%zu\n" \
26         "Number of dead records: %zu\n" \
27         "Smallest/average/largest dead records: %zu/%zu/%zu\n" \
28         "Number of free records: %zu\n" \
29         "Smallest/average/largest free records: %zu/%zu/%zu\n" \
30         "Number of hash chains: %zu\n" \
31         "Smallest/average/largest hash chains: %zu/%zu/%zu\n" \
32         "Number of uncoalesced records: %zu\n" \
33         "Smallest/average/largest uncoalesced runs: %zu/%zu/%zu\n" \
34         "Percentage keys/data/padding/free/dead/rechdrs&tailers/hashes: %.0f/%.0f/%.0f/%.0f/%.0f/%.0f/%.0f\n"
35
36 /* We don't use tally module, to keep upstream happy. */
37 struct tally {
38         size_t min, max, total;
39         size_t num;
40 };
41
42 static void tally_init(struct tally *tally)
43 {
44         tally->total = 0;
45         tally->num = 0;
46         tally->min = tally->max = 0;
47 }
48
49 static void tally_add(struct tally *tally, size_t len)
50 {
51         if (tally->num == 0)
52                 tally->max = tally->min = len;
53         else if (len > tally->max)
54                 tally->max = len;
55         else if (len < tally->min)
56                 tally->min = len;
57         tally->num++;
58         tally->total += len;
59 }
60
61 static size_t tally_mean(const struct tally *tally)
62 {
63         if (!tally->num)
64                 return 0;
65         return tally->total / tally->num;
66 }
67
68 static size_t get_hash_length(struct tdb_context *tdb, unsigned int i)
69 {
70         tdb_off_t rec_ptr;
71         size_t count = 0;
72
73         if (tdb_ofs_read(tdb, TDB_HASH_TOP(i), &rec_ptr) == -1)
74                 return 0;
75
76         /* keep looking until we find the right record */
77         while (rec_ptr) {
78                 struct tdb_record r;
79                 ++count;
80                 if (tdb_rec_read(tdb, rec_ptr, &r) == -1)
81                         return 0;
82                 rec_ptr = r.next;
83         }
84         return count;
85 }
86
87 char *tdb_summary(struct tdb_context *tdb)
88 {
89         tdb_off_t off;
90         struct tally freet, keys, data, dead, extra, hash, uncoal;
91         struct tdb_record rec;
92         char *ret = NULL;
93         bool locked;
94         size_t len, unc = 0;
95
96         /* Read-only databases use no locking at all: it's best-effort.
97          * We may have a write lock already, so skip that case too. */
98         if (tdb->read_only || tdb->allrecord_lock.count != 0) {
99                 locked = false;
100         } else {
101                 if (tdb_lockall_read(tdb) == -1)
102                         return NULL;
103                 locked = true;
104         }
105
106         tally_init(&freet);
107         tally_init(&keys);
108         tally_init(&data);
109         tally_init(&dead);
110         tally_init(&extra);
111         tally_init(&hash);
112         tally_init(&uncoal);
113
114         for (off = TDB_DATA_START(tdb->header.hash_size);
115              off < tdb->map_size - 1;
116              off += sizeof(rec) + rec.rec_len) {
117                 if (tdb->methods->tdb_read(tdb, off, &rec, sizeof(rec),
118                                            DOCONV()) == -1)
119                         goto unlock;
120                 switch (rec.magic) {
121                 case TDB_MAGIC:
122                         tally_add(&keys, rec.key_len);
123                         tally_add(&data, rec.data_len);
124                         tally_add(&extra, rec.rec_len - (rec.key_len
125                                                          + rec.data_len));
126                         if (unc > 1)
127                                 tally_add(&uncoal, unc - 1);
128                         unc = 0;
129                         break;
130                 case TDB_FREE_MAGIC:
131                         tally_add(&freet, rec.rec_len);
132                         unc++;
133                         break;
134                 /* If we crash after ftruncate, we can get zeroes or fill. */
135                 case TDB_RECOVERY_INVALID_MAGIC:
136                 case 0x42424242:
137                         unc++;
138                         rec.rec_len = tdb_dead_space(tdb, off) - sizeof(rec);
139                         /* Fall through */
140                 case TDB_DEAD_MAGIC:
141                         tally_add(&dead, rec.rec_len);
142                         break;
143                 default:
144                         TDB_LOG((tdb, TDB_DEBUG_ERROR,
145                                  "Unexpected record magic 0x%x at offset %d\n",
146                                  rec.magic, off));
147                         goto unlock;
148                 }
149         }
150         if (unc > 1)
151                 tally_add(&uncoal, unc - 1);
152
153         for (off = 0; off < tdb->header.hash_size; off++)
154                 tally_add(&hash, get_hash_length(tdb, off));
155
156         /* 20 is max length of a %zu. */
157         len = strlen(SUMMARY_FORMAT) + 35*20 + 1;
158         ret = malloc(len);
159         if (!ret)
160                 goto unlock;
161
162         sprintf(ret, SUMMARY_FORMAT,
163                 tdb->map_size, keys.total+data.total,
164                 keys.num,
165                 keys.min, tally_mean(&keys), keys.max,
166                 data.min, tally_mean(&data), data.max,
167                 extra.min, tally_mean(&extra), extra.max,
168                 dead.num,
169                 dead.min, tally_mean(&dead), dead.max,
170                 freet.num,
171                 freet.min, tally_mean(&freet), freet.max,
172                 hash.num,
173                 hash.min, tally_mean(&hash), hash.max,
174                 uncoal.total,
175                 uncoal.min, tally_mean(&uncoal), uncoal.max,
176                 keys.total * 100.0 / tdb->map_size,
177                 data.total * 100.0 / tdb->map_size,
178                 extra.total * 100.0 / tdb->map_size,
179                 freet.total * 100.0 / tdb->map_size,
180                 dead.total * 100.0 / tdb->map_size,
181                 (keys.num + freet.num + dead.num)
182                 * (sizeof(struct tdb_record) + sizeof(uint32_t))
183                 * 100.0 / tdb->map_size,
184                 tdb->header.hash_size * sizeof(tdb_off_t)
185                 * 100.0 / tdb->map_size);
186
187 unlock:
188         if (locked) {
189                 tdb_unlockall_read(tdb);
190         }
191         return ret;
192 }