summaryrefslogtreecommitdiffstats
path: root/lib/tdb/common/summary.c
blob: a93eb93e734123041b0aafb7bc22ddb89e61866e (plain)
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
 /*
   Trivial Database: human-readable summary code
   Copyright (C) Rusty Russell 2010

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 3 of the License, or (at your option) any later version.

   This library 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#include "tdb_private.h"

#define SUMMARY_FORMAT \
	"Size of file/data: %llu/%zu\n" \
	"Header offset/logical size: %zu/%zu\n" \
	"Number of records: %zu\n" \
	"Incompatible hash: %s\n" \
	"Active/supported feature flags: 0x%08x/0x%08x\n" \
	"Robust mutexes locking: %s\n" \
	"Smallest/average/largest keys: %zu/%zu/%zu\n" \
	"Smallest/average/largest data: %zu/%zu/%zu\n" \
	"Smallest/average/largest padding: %zu/%zu/%zu\n" \
	"Number of dead records: %zu\n" \
	"Smallest/average/largest dead records: %zu/%zu/%zu\n" \
	"Number of free records: %zu\n" \
	"Smallest/average/largest free records: %zu/%zu/%zu\n" \
	"Number of hash chains: %zu\n" \
	"Smallest/average/largest hash chains: %zu/%zu/%zu\n" \
	"Number of uncoalesced records: %zu\n" \
	"Smallest/average/largest uncoalesced runs: %zu/%zu/%zu\n" \
	"Percentage keys/data/padding/free/dead/rechdrs&tailers/hashes: %.0f/%.0f/%.0f/%.0f/%.0f/%.0f/%.0f\n"

/* We don't use tally module, to keep upstream happy. */
struct tally {
	size_t min, max, total;
	size_t num;
};

static void tally_init(struct tally *tally)
{
	tally->total = 0;
	tally->num = 0;
	tally->min = tally->max = 0;
}

static void tally_add(struct tally *tally, size_t len)
{
	if (tally->num == 0)
		tally->max = tally->min = len;
	else if (len > tally->max)
		tally->max = len;
	else if (len < tally->min)
		tally->min = len;
	tally->num++;
	tally->total += len;
}

static size_t tally_mean(const struct tally *tally)
{
	if (!tally->num)
		return 0;
	return tally->total / tally->num;
}

static size_t get_hash_length(struct tdb_context *tdb, unsigned int i)
{
	tdb_off_t rec_ptr;
	struct tdb_chainwalk_ctx chainwalk;
	size_t count = 0;

	if (tdb_ofs_read(tdb, TDB_HASH_TOP(i), &rec_ptr) == -1)
		return 0;

	tdb_chainwalk_init(&chainwalk, rec_ptr);

	/* keep looking until we find the right record */
	while (rec_ptr) {
		struct tdb_record r;
		bool ok;
		++count;
		if (tdb_rec_read(tdb, rec_ptr, &r) == -1)
			return 0;
		rec_ptr = r.next;
		ok = tdb_chainwalk_check(tdb, &chainwalk, rec_ptr);
		if (!ok) {
			return SIZE_MAX;
		}
	}
	return count;
}

_PUBLIC_ char *tdb_summary(struct tdb_context *tdb)
{
	off_t file_size;
	tdb_off_t off, rec_off;
	struct tally freet, keys, data, dead, extra, hashval, uncoal;
	struct tdb_record rec;
	char *ret = NULL;
	bool locked;
	size_t unc = 0;
	int len;
	struct tdb_record recovery;

	/* Read-only databases use no locking at all: it's best-effort.
	 * We may have a write lock already, so skip that case too. */
	if (tdb->read_only || tdb->allrecord_lock.count != 0) {
		locked = false;
	} else {
		if (tdb_lockall_read(tdb) == -1)
			return NULL;
		locked = true;
	}

	if (tdb_recovery_area(tdb, tdb->methods, &rec_off, &recovery) != 0) {
		goto unlock;
	}

	tally_init(&freet);
	tally_init(&keys);
	tally_init(&data);
	tally_init(&dead);
	tally_init(&extra);
	tally_init(&hashval);
	tally_init(&uncoal);

	for (off = TDB_DATA_START(tdb->hash_size);
	     off < tdb->map_size - 1;
	     off += sizeof(rec) + rec.rec_len) {
		if (tdb->methods->tdb_read(tdb, off, &rec, sizeof(rec),
					   DOCONV()) == -1)
			goto unlock;
		switch (rec.magic) {
		case TDB_MAGIC:
			tally_add(&keys, rec.key_len);
			tally_add(&data, rec.data_len);
			tally_add(&extra, rec.rec_len - (rec.key_len
							 + rec.data_len));
			if (unc > 1)
				tally_add(&uncoal, unc - 1);
			unc = 0;
			break;
		case TDB_FREE_MAGIC:
			tally_add(&freet, rec.rec_len);
			unc++;
			break;
		/* If we crash after ftruncate, we can get zeroes or fill. */
		case TDB_RECOVERY_INVALID_MAGIC:
		case 0x42424242:
			unc++;
			/* If it's a valid recovery, we can trust rec_len. */
			if (off != rec_off) {
				rec.rec_len = tdb_dead_space(tdb, off)
					- sizeof(rec);
			}

			FALL_THROUGH;
		case TDB_DEAD_MAGIC:
			tally_add(&dead, rec.rec_len);
			break;
		default:
			TDB_LOG((tdb, TDB_DEBUG_ERROR,
				 "Unexpected record magic 0x%x at offset %u\n",
				 rec.magic, off));
			goto unlock;
		}
	}
	if (unc > 1)
		tally_add(&uncoal, unc - 1);

	for (off = 0; off < tdb->hash_size; off++)
		tally_add(&hashval, get_hash_length(tdb, off));

	file_size = tdb->hdr_ofs + tdb->map_size;

	len = asprintf(&ret, SUMMARY_FORMAT,
		 (unsigned long long)file_size, keys.total+data.total,
		 (size_t)tdb->hdr_ofs, (size_t)tdb->map_size,
		 keys.num,
		 (tdb->hash_fn == tdb_jenkins_hash)?"yes":"no",
		 (unsigned)tdb->feature_flags, TDB_SUPPORTED_FEATURE_FLAGS,
		 (tdb->feature_flags & TDB_FEATURE_FLAG_MUTEX)?"yes":"no",
		 keys.min, tally_mean(&keys), keys.max,
		 data.min, tally_mean(&data), data.max,
		 extra.min, tally_mean(&extra), extra.max,
		 dead.num,
		 dead.min, tally_mean(&dead), dead.max,
		 freet.num,
		 freet.min, tally_mean(&freet), freet.max,
		 hashval.num,
		 hashval.min, tally_mean(&hashval), hashval.max,
		 uncoal.total,
		 uncoal.min, tally_mean(&uncoal), uncoal.max,
		 keys.total * 100.0 / file_size,
		 data.total * 100.0 / file_size,
		 extra.total * 100.0 / file_size,
		 freet.total * 100.0 / file_size,
		 dead.total * 100.0 / file_size,
		 (keys.num + freet.num + dead.num)
		 * (sizeof(struct tdb_record) + sizeof(uint32_t))
		 * 100.0 / file_size,
		 tdb->hash_size * sizeof(tdb_off_t)
		 * 100.0 / file_size);
	if (len == -1) {
		goto unlock;
	}

unlock:
	if (locked) {
		tdb_unlockall_read(tdb);
	}
	return ret;
}