memset(&stats->allocs, 0, (char *)(stats+1) - (char *)&stats->allocs);
 }
 
+static void tdb_log(struct tdb_context *tdb, enum tdb_log_level level,
+                   void *private, const char *message)
+{
+       fputs(message, stderr);
+}
+
 int main(int argc, char *argv[])
 {
        unsigned int i, j, num = 1000, stage = 0, stopat = -1;
        int flags = TDB_DEFAULT;
-       bool transaction = false;
+       bool transaction = false, summary = false;
        TDB_DATA key, data;
        struct tdb_context *tdb;
        struct timeval start, stop;
-       union tdb_attribute seed, stats;
+       union tdb_attribute seed, stats, log;
        enum TDB_ERROR ecode;
 
        /* Try to keep benchmarks even. */
        seed.base.next = NULL;
        seed.seed.seed = 0;
 
+       log.base.attr = TDB_ATTRIBUTE_LOG;
+       log.base.next = &seed;
+       log.log.log_fn = tdb_log;
+
        memset(&stats, 0, sizeof(stats));
        stats.base.attr = TDB_ATTRIBUTE_STATS;
        stats.base.next = NULL;
                argc--;
                argv++;
        }
+       if (argv[1] && strcmp(argv[1], "--summary") == 0) {
+               summary = true;
+               argc--;
+               argv++;
+       }
        if (argv[1] && strcmp(argv[1], "--stats") == 0) {
                seed.base.next = &stats;
                argc--;
        }
 
        tdb = tdb_open("/tmp/speed.tdb", flags, O_RDWR|O_CREAT|O_TRUNC,
-                      0600, &seed);
+                      0600, &log);
        if (!tdb)
                err(1, "Opening /tmp/speed.tdb");
 
        printf(" %zu ns (%zu bytes)\n",
               normalize(&start, &stop, num), file_size());
 
+       if (summary) {
+               char *sumstr = NULL;
+               tdb_summary(tdb, TDB_SUMMARY_HISTOGRAMS, &sumstr);
+               printf("%s\n", sumstr);
+               free(sumstr);
+       }
        if (seed.base.next)
                dump_and_clear_stats(&stats.stats);
        if (++stage == stopat)
                errx(1, "committing transaction: %s", tdb_errorstr(ecode));
        printf(" %zu ns (%zu bytes)\n",
               normalize(&start, &stop, num), file_size());
+       if (summary) {
+               char *sumstr = NULL;
+               tdb_summary(tdb, TDB_SUMMARY_HISTOGRAMS, &sumstr);
+               printf("%s\n", sumstr);
+               free(sumstr);
+       }
        if (seed.base.next)
                dump_and_clear_stats(&stats.stats);
        if (++stage == stopat)
                errx(1, "committing transaction: %s", tdb_errorstr(ecode));
        printf(" %zu ns (%zu bytes)\n",
               normalize(&start, &stop, num), file_size());
+       if (summary) {
+               char *sumstr = NULL;
+               tdb_summary(tdb, TDB_SUMMARY_HISTOGRAMS, &sumstr);
+               printf("%s\n", sumstr);
+               free(sumstr);
+       }
        if (seed.base.next)
                dump_and_clear_stats(&stats.stats);
        if (++stage == stopat)
                errx(1, "committing transaction: %s", tdb_errorstr(ecode));
        printf(" %zu ns (%zu bytes)\n",
               normalize(&start, &stop, num), file_size());
+       if (summary) {
+               char *sumstr = NULL;
+               tdb_summary(tdb, TDB_SUMMARY_HISTOGRAMS, &sumstr);
+               printf("%s\n", sumstr);
+               free(sumstr);
+       }
        if (seed.base.next)
                dump_and_clear_stats(&stats.stats);
        if (++stage == stopat)
                errx(1, "committing transaction: %s", tdb_errorstr(ecode));
        printf(" %zu ns (%zu bytes)\n",
               normalize(&start, &stop, num), file_size());
+       if (summary) {
+               char *sumstr = NULL;
+               tdb_summary(tdb, TDB_SUMMARY_HISTOGRAMS, &sumstr);
+               printf("%s\n", sumstr);
+               free(sumstr);
+       }
        if (seed.base.next)
                dump_and_clear_stats(&stats.stats);
        if (++stage == stopat)
                errx(1, "committing transaction: %s", tdb_errorstr(ecode));
        printf(" %zu ns (%zu bytes)\n",
               normalize(&start, &stop, num), file_size());
+       if (summary) {
+               char *sumstr = NULL;
+               tdb_summary(tdb, TDB_SUMMARY_HISTOGRAMS, &sumstr);
+               printf("%s\n", sumstr);
+               free(sumstr);
+       }
        if (seed.base.next)
                dump_and_clear_stats(&stats.stats);
        if (++stage == stopat)
 
        if (transaction && (ecode = tdb_transaction_start(tdb)))
                errx(1, "starting transaction: %s", tdb_errorstr(ecode));
-
        /* Append 1000 records. */
        printf("Appending %u records: ", num); fflush(stdout);
        gettimeofday(&start, NULL);
                errx(1, "committing transaction: %s", tdb_errorstr(ecode));
        printf(" %zu ns (%zu bytes)\n",
               normalize(&start, &stop, num), file_size());
+       if (summary) {
+               char *sumstr = NULL;
+               tdb_summary(tdb, TDB_SUMMARY_HISTOGRAMS, &sumstr);
+               printf("%s\n", sumstr);
+               free(sumstr);
+       }
        if (++stage == stopat)
                exit(0);
 
        printf(" %zu ns (%zu bytes)\n",
               normalize(&start, &stop, num), file_size());
 
+       if (summary) {
+               char *sumstr = NULL;
+               tdb_summary(tdb, TDB_SUMMARY_HISTOGRAMS, &sumstr);
+               printf("%s\n", sumstr);
+               free(sumstr);
+       }
        if (seed.base.next)
                dump_and_clear_stats(&stats.stats);
        if (++stage == stopat)