check_type: fix incorrect documentation.
[ccan] / ccan / tdb2 / tdb1_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 "tdb1_private.h"
19
20 #define SUMMARY_FORMAT1 \
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 tally1_init(struct tally *tally)
43 {
44         tally->total = 0;
45         tally->num = 0;
46         tally->min = tally->max = 0;
47 }
48
49 static void tally1_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 tally1_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         tdb1_off_t rec_ptr;
71         size_t count = 0;
72
73         if (tdb1_ofs_read(tdb, TDB1_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 tdb1_record r;
79                 ++count;
80                 if (tdb1_rec_read(tdb, rec_ptr, &r) == -1)
81                         return 0;
82                 rec_ptr = r.next;
83         }
84         return count;
85 }
86
87 char *tdb1_summary(struct tdb_context *tdb)
88 {
89         tdb1_off_t off, rec_off;
90         struct tally freet, keys, data, dead, extra, hash, uncoal;
91         struct tdb1_record rec;
92         char *ret = NULL;
93         bool locked;
94         size_t len, unc = 0;
95         struct tdb1_record recovery;
96
97         /* We may have a write lock already, so don't lock. */
98         if (tdb->file->allrecord_lock.count != 0) {
99                 locked = false;
100         } else {
101                 if (tdb_lockall_read(tdb) != TDB_SUCCESS)
102                         return NULL;
103                 locked = true;
104         }
105
106         if (tdb1_recovery_area(tdb, tdb->tdb1.io, &rec_off, &recovery) != 0) {
107                 goto unlock;
108         }
109
110         tally1_init(&freet);
111         tally1_init(&keys);
112         tally1_init(&data);
113         tally1_init(&dead);
114         tally1_init(&extra);
115         tally1_init(&hash);
116         tally1_init(&uncoal);
117
118         for (off = TDB1_DATA_START(tdb->tdb1.header.hash_size);
119              off < tdb->file->map_size - 1;
120              off += sizeof(rec) + rec.rec_len) {
121                 if (tdb->tdb1.io->tdb1_read(tdb, off, &rec, sizeof(rec),
122                                            TDB1_DOCONV()) == -1)
123                         goto unlock;
124                 switch (rec.magic) {
125                 case TDB1_MAGIC:
126                         tally1_add(&keys, rec.key_len);
127                         tally1_add(&data, rec.data_len);
128                         tally1_add(&extra, rec.rec_len - (rec.key_len
129                                                          + rec.data_len));
130                         if (unc > 1)
131                                 tally1_add(&uncoal, unc - 1);
132                         unc = 0;
133                         break;
134                 case TDB1_FREE_MAGIC:
135                         tally1_add(&freet, rec.rec_len);
136                         unc++;
137                         break;
138                 /* If we crash after ftruncate, we can get zeroes or fill. */
139                 case TDB1_RECOVERY_INVALID_MAGIC:
140                 case 0x42424242:
141                         unc++;
142                         /* If it's a valid recovery, we can trust rec_len. */
143                         if (off != rec_off) {
144                                 rec.rec_len = tdb1_dead_space(tdb, off)
145                                         - sizeof(rec);
146                         }
147                         /* Fall through */
148                 case TDB1_DEAD_MAGIC:
149                         tally1_add(&dead, rec.rec_len);
150                         break;
151                 default:
152                         tdb->last_error = tdb_logerr(tdb, TDB_ERR_CORRUPT,
153                                                 TDB_LOG_ERROR,
154                                                 "Unexpected record magic 0x%x"
155                                                 " at offset %d",
156                                                 rec.magic, off);
157                         goto unlock;
158                 }
159         }
160         if (unc > 1)
161                 tally1_add(&uncoal, unc - 1);
162
163         for (off = 0; off < tdb->tdb1.header.hash_size; off++)
164                 tally1_add(&hash, get_hash_length(tdb, off));
165
166         /* 20 is max length of a %zu. */
167         len = strlen(SUMMARY_FORMAT1) + 35*20 + 1;
168         ret = (char *)malloc(len);
169         if (!ret)
170                 goto unlock;
171
172         snprintf(ret, len, SUMMARY_FORMAT1,
173                  (tdb1_len_t)tdb->file->map_size, keys.total+data.total,
174                  keys.num,
175                  keys.min, tally1_mean(&keys), keys.max,
176                  data.min, tally1_mean(&data), data.max,
177                  extra.min, tally1_mean(&extra), extra.max,
178                  dead.num,
179                  dead.min, tally1_mean(&dead), dead.max,
180                  freet.num,
181                  freet.min, tally1_mean(&freet), freet.max,
182                  hash.num,
183                  hash.min, tally1_mean(&hash), hash.max,
184                  uncoal.total,
185                  uncoal.min, tally1_mean(&uncoal), uncoal.max,
186                  keys.total * 100.0 / tdb->file->map_size,
187                  data.total * 100.0 / tdb->file->map_size,
188                  extra.total * 100.0 / tdb->file->map_size,
189                  freet.total * 100.0 / tdb->file->map_size,
190                  dead.total * 100.0 / tdb->file->map_size,
191                  (keys.num + freet.num + dead.num)
192                  * (sizeof(struct tdb1_record) + sizeof(uint32_t))
193                  * 100.0 / tdb->file->map_size,
194                  tdb->tdb1.header.hash_size * sizeof(tdb1_off_t)
195                  * 100.0 / (tdb1_len_t)tdb->file->map_size);
196
197 unlock:
198         if (locked) {
199                 tdb_unlockall_read(tdb);
200         }
201         return ret;
202 }