git.ozlabs.org Git - ccan/blob - 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 #include <ccan/tally/tally.h>
  20
  21 #define SUMMARY_FORMAT \
  22         "Size of file/data: %zu/%zu\n" \
  23         "Number of records: %zu\n" \
  24         "Smallest/average/largest keys: %zu/%zu/%zu\n%s" \
  25         "Smallest/average/largest data: %zu/%zu/%zu\n%s" \
  26         "Smallest/average/largest padding: %zu/%zu/%zu\n%s" \
  27         "Number of dead records: %zu\n" \
  28         "Smallest/average/largest dead records: %zu/%zu/%zu\n%s" \
  29         "Number of free records: %zu\n" \
  30         "Smallest/average/largest free records: %zu/%zu/%zu\n%s" \
  31         "Number of hash chains: %zu\n" \
  32         "Smallest/average/largest hash chains: %zu/%zu/%zu\n%s" \
  33         "Number of uncoalesced records: %zu\n" \
  34         "Smallest/average/largest uncoalesced runs: %zu/%zu/%zu\n%s" \
  35         "Percentage keys/data/padding/free/dead/rechdrs&tailers/hashes: %.0f/%.0f/%.0f/%.0f/%.0f/%.0f/%.0f\n"
  36
  37 #define HISTO_WIDTH 70
  38 #define HISTO_HEIGHT 20
  39
  40 /* Slow, but should be very rare. */
  41 static size_t dead_space(struct tdb_context *tdb, tdb_off_t off)
  42 {
  43         size_t len;
  44
  45         for (len = 0; off + len < tdb->map_size; len++) {
  46                 char c;
  47                 if (tdb->methods->tdb_read(tdb, off, &c, 1, 0))
  48                         return 0;
  49                 if (c != 0 && c != 0x42)
  50                         break;
  51         }
  52         return len;
  53 }
  54
  55 static size_t get_hash_length(struct tdb_context *tdb, unsigned int i)
  56 {
  57         tdb_off_t rec_ptr;
  58         size_t count = 0;
  59
  60         if (tdb_ofs_read(tdb, TDB_HASH_TOP(i), &rec_ptr) == -1)
  61                 return 0;
  62
  63         /* keep looking until we find the right record */
  64         while (rec_ptr) {
  65                 struct tdb_record r;
  66                 ++count;
  67                 if (tdb_rec_read(tdb, rec_ptr, &r) == -1)
  68                         return 0;
  69                 rec_ptr = r.next;
  70         }
  71         return count;
  72 }
  73
  74 char *tdb_summary(struct tdb_context *tdb, enum tdb_summary_flags flags)
  75 {
  76         tdb_off_t off;
  77         struct tally *freet, *keys, *data, *dead, *extra, *hash, *uncoal;
  78         char *freeg, *keysg, *datag, *deadg, *extrag, *hashg, *uncoalg;
  79         struct tdb_record rec;
  80         char *ret = NULL;
  81         bool locked;
  82         size_t len, unc = 0;
  83
  84         freeg = keysg = datag = deadg = extrag = hashg = uncoalg = NULL;
  85
  86         /* Read-only databases use no locking at all: it's best-effort.
  87          * We may have a write lock already, so skip that case too. */
  88         if (tdb->read_only || tdb->allrecord_lock.count != 0) {
  89                 locked = false;
  90         } else {
  91                 if (tdb_lockall_read(tdb) == -1)
  92                         return NULL;
  93                 locked = true;
  94         }
  95
  96         freet = tally_new(HISTO_HEIGHT);
  97         keys = tally_new(HISTO_HEIGHT);
  98         data = tally_new(HISTO_HEIGHT);
  99         dead = tally_new(HISTO_HEIGHT);
 100         extra = tally_new(HISTO_HEIGHT);
 101         hash = tally_new(HISTO_HEIGHT);
 102         uncoal = tally_new(HISTO_HEIGHT);
 103         if (!freet || !keys || !data || !dead || !extra || !hash || !uncoal) {
 104                 tdb->ecode = TDB_ERR_OOM;
 105                 goto unlock;
 106         }
 107
 108         for (off = TDB_DATA_START(tdb->header.hash_size);
 109              off < tdb->map_size - 1;
 110              off += sizeof(rec) + rec.rec_len) {
 111                 if (tdb->methods->tdb_read(tdb, off, &rec, sizeof(rec),
 112                                            DOCONV()) == -1)
 113                         goto unlock;
 114                 switch (rec.magic) {
 115                 case TDB_MAGIC:
 116                         tally_add(keys, rec.key_len);
 117                         tally_add(data, rec.data_len);
 118                         tally_add(extra, rec.rec_len - (rec.key_len
 119                                                         + rec.data_len));
 120                         break;
 121                 case TDB_FREE_MAGIC:
 122                         tally_add(freet, rec.rec_len);
 123                         unc++;
 124                         break;
 125                 /* If we crash after ftruncate, we can get zeroes or fill. */
 126                 case TDB_RECOVERY_INVALID_MAGIC:
 127                 case 0x42424242:
 128                         unc++;
 129                         rec.rec_len = dead_space(tdb, off) - sizeof(rec);
 130                         /* Fall through */
 131                 case TDB_DEAD_MAGIC:
 132                         tally_add(dead, rec.rec_len);
 133                         break;
 134                 default:
 135                         TDB_LOG((tdb, TDB_DEBUG_ERROR,
 136                                  "Unexpected record magic 0x%x at offset %d\n",
 137                                  rec.magic, off));
 138                         goto unlock;
 139                 }
 140
 141                 if (unc &&
 142                     (rec.magic == TDB_MAGIC || rec.magic == TDB_DEAD_MAGIC)) {
 143                         tally_add(uncoal, unc);
 144                         unc = 0;
 145                 }
 146         }
 147         if (unc)
 148                 tally_add(uncoal, unc);
 149
 150         for (off = 0; off < tdb->header.hash_size; off++)
 151                 tally_add(hash, get_hash_length(tdb, off));
 152
 153         if (flags & TDB_SUMMARY_HISTOGRAMS) {
 154                 freeg = tally_histogram(freet, HISTO_WIDTH, HISTO_HEIGHT);
 155                 keysg = tally_histogram(keys, HISTO_WIDTH, HISTO_HEIGHT);
 156                 datag = tally_histogram(data, HISTO_WIDTH, HISTO_HEIGHT);
 157                 deadg = tally_histogram(dead, HISTO_WIDTH, HISTO_HEIGHT);
 158                 extrag = tally_histogram(extra, HISTO_WIDTH, HISTO_HEIGHT);
 159                 hashg = tally_histogram(hash, HISTO_WIDTH, HISTO_HEIGHT);
 160                 uncoalg = tally_histogram(uncoal, HISTO_WIDTH, HISTO_HEIGHT);
 161         }
 162
 163         /* 20 is max length of a %zu. */
 164         len = strlen(SUMMARY_FORMAT) + 29*20 + 1
 165                 + (freeg ? strlen(freeg) : 0)
 166                 + (keysg ? strlen(keysg) : 0)
 167                 + (datag ? strlen(datag) : 0)
 168                 + (deadg ? strlen(deadg) : 0)
 169                 + (extrag ? strlen(extrag) : 0)
 170                 + (hashg ? strlen(hashg) : 0)
 171                 + (uncoalg ? strlen(uncoalg) : 0);
 172         ret = malloc(len);
 173         if (!ret)
 174                 goto unlock;
 175
 176         sprintf(ret, SUMMARY_FORMAT,
 177                 tdb->map_size, tally_total(keys, NULL)+tally_total(data, NULL),
 178                 tally_num(keys),
 179                 tally_min(keys), tally_mean(keys), tally_max(keys),
 180                 keysg ? keysg : "",
 181                 tally_min(data), tally_mean(data), tally_max(data),
 182                 datag ? datag : "",
 183                 tally_min(extra), tally_mean(extra), tally_max(extra),
 184                 extrag ? extrag : "",
 185                 tally_num(dead),
 186                 tally_min(dead), tally_mean(dead), tally_max(dead),
 187                 deadg ? deadg : "",
 188                 tally_num(freet),
 189                 tally_min(freet), tally_mean(freet), tally_max(freet),
 190                 freeg ? freeg : "",
 191                 tally_num(hash),
 192                 tally_min(hash), tally_mean(hash), tally_max(hash),
 193                 hashg ? hashg : "",
 194                 tally_total(uncoal, NULL),
 195                 tally_min(uncoal), tally_mean(uncoal), tally_max(uncoal),
 196                 uncoalg ? uncoalg : "",
 197                 tally_total(keys, NULL) * 100.0 / tdb->map_size,
 198                 tally_total(data, NULL) * 100.0 / tdb->map_size,
 199                 tally_total(extra, NULL) * 100.0 / tdb->map_size,
 200                 tally_total(freet, NULL) * 100.0 / tdb->map_size,
 201                 tally_total(dead, NULL) * 100.0 / tdb->map_size,
 202                 (tally_num(keys) + tally_num(freet) + tally_num(dead))
 203                 * (sizeof(struct tdb_record) + sizeof(uint32_t))
 204                 * 100.0 / tdb->map_size,
 205                 tdb->header.hash_size * sizeof(tdb_off_t)
 206                 * 100.0 / tdb->map_size);
 207
 208 unlock:
 209         free(freeg);
 210         free(keysg);
 211         free(datag);
 212         free(deadg);
 213         free(extrag);
 214         free(hashg);
 215         free(uncoalg);
 216         free(freet);
 217         free(keys);
 218         free(data);
 219         free(dead);
 220         free(extra);
 221         free(hash);
 222         free(uncoal);
 223         if (locked) {
 224                 tdb_unlockall_read(tdb);
 225         }
 226         return ret;
 227 }