#
#
# patch "NEWS"
#  from [a9412ab044bd25db67edc1625131737f1450e45a]
#    to [b883957ce622f6c3054feff841488eb971a9e79d]
# 
# patch "cmd_db.cc"
#  from [ddc1958a87b2e73ffb96f2d1774340d1d42810b1]
#    to [1ed3e071783afad66d6bb81ee3b8b30604f15c8f]
# 
# patch "database.cc"
#  from [d0da4979961345a3f6f4b68769910f3ba3943f81]
#    to [72d5286b3568dce70e0e1b281eadf8eda3f787d4]
# 
# patch "database.hh"
#  from [40e06a31c4d18cf50a9a3f3f46bb2d14df06fe68]
#    to [31ba75343ca21813eb814b814d6576440f4f0cfc]
#
============================================================
--- NEWS	a9412ab044bd25db67edc1625131737f1450e45a
+++ NEWS	b883957ce622f6c3054feff841488eb971a9e79d
@@ -1,6 +1,11 @@ conflicts, move after landing on mainlin
 New stuff from nvm.dates* (written on top so as to avoid tedious merge
 conflicts, move after landing on mainline):
 
+        New features
+
+        - Additional '--full' option for 'mtn db info' to display some
+        statistic analysis of the date certs in the database.
+
         Internal
 
         - Using 64 bit integer values to represent dates internally. This
============================================================
--- cmd_db.cc	ddc1958a87b2e73ffb96f2d1774340d1d42810b1
+++ cmd_db.cc	1ed3e071783afad66d6bb81ee3b8b30604f15c8f
@@ -50,13 +50,13 @@ CMD(db_info, "info", "", CMD_REF(db), ""
 CMD(db_info, "info", "", CMD_REF(db), "",
     N_("Shows information about the database"),
     "",
-    options::opts::none)
+    options::opts::full)
 {
   N(args.size() == 0,
     F("no arguments needed"));
 
   database db(app);
-  db.info(cout);
+  db.info(cout, app.opts.full);
 }
 
 CMD(db_version, "version", "", CMD_REF(db), "",
============================================================
--- database.cc	d0da4979961345a3f6f4b68769910f3ba3943f81
+++ database.cc	72d5286b3568dce70e0e1b281eadf8eda3f787d4
@@ -13,6 +13,7 @@
 #include <fstream>
 #include <iterator>
 #include <list>
+#include <numeric>
 #include <set>
 #include <sstream>
 #include "vector.hh"
@@ -79,6 +80,7 @@ using std::vector;
 using std::set;
 using std::string;
 using std::vector;
+using std::accumulate;
 
 using boost::shared_ptr;
 using boost::shared_dynamic_cast;
@@ -840,7 +842,7 @@ void
 
 
 void
-database::info(ostream & out)
+database::info(ostream & out, bool analyze)
 {
   // don't check the schema
   ensure_open_for_maintenance();
@@ -971,6 +973,157 @@ database::info(ostream & out)
   form = form % imp->cache_size();
 
   out << form.str() << '\n'; // final newline is kept out of the translation
+
+  // the following analyzation is only done for --full info
+  if (!analyze)
+    return;
+
+
+  typedef map<revision_id, date_t> rev_date;
+  rev_date rd;
+  vector<cert> certs;
+
+  L(FL("fetching revision dates"));
+  imp->get_certs(date_cert_name, certs, "revision_certs");
+
+  L(FL("analyzing revision dates"));
+  rev_date::iterator d;
+  for (vector<cert>::iterator i = certs.begin(); i != certs.end(); ++i)
+    {
+      date_t cert_date;
+      try
+        {
+          cert_date = date_t::from_string(i->value());
+        }
+      catch (informative_failure & e)
+        {
+          // simply skip dates we cannot parse
+          W(F("invalid date: %s for revision %s, skipped")
+            % i->value() % i->ident);
+        }
+
+      if (cert_date.valid())
+        {
+          if ((d = rd.find(i->ident)) == rd.end())
+            rd.insert(make_pair(i->ident, cert_date));
+          else
+            {
+              if (d->second > cert_date)
+                d->second = cert_date;
+            }
+        }
+    }
+
+  L(FL("fetching ancestry map"));
+  typedef multimap<revision_id, revision_id>::const_iterator gi;
+  rev_ancestry_map graph;
+  get_revision_ancestry(graph);
+
+  L(FL("checking timestamps differences of related revisions"));
+  int correct = 0,
+      equal = 0,
+      incorrect = 0,
+      root_anc = 0,
+      missing = 0;
+
+  vector<s64> diffs;
+  u64 diff_sum = 0;
+
+  for (gi i = graph.begin(); i != graph.end(); ++i)
+    {
+      revision_id anc_rid = i->first,
+                  desc_rid = i->second;
+
+      if (null_id(anc_rid))
+        {
+          root_anc++;
+          continue;
+        }
+      I(!null_id(desc_rid));
+
+      date_t anc_date,
+             desc_date;
+
+      map<revision_id, date_t>::iterator j;
+      if ((j = rd.find(anc_rid)) != rd.end())
+        anc_date = j->second;
+
+      if ((j = rd.find(desc_rid)) != rd.end())
+        desc_date = j->second;
+
+      if (anc_date.valid() && desc_date.valid())
+        {
+          // we only need seconds precision here
+          s64 diff = (desc_date - anc_date) / 1000;
+          diffs.push_back(diff);
+
+          if (anc_date < desc_date)
+            correct++;
+          else if (anc_date == desc_date)
+            equal++;
+          else
+            {
+              L(FL("   rev %s -> rev %s") % anc_rid % desc_rid);
+              L(FL("   but date %s ! -> %s")
+                % anc_date.as_iso_8601_extended()
+                % desc_date.as_iso_8601_extended());
+              L(FL("   (difference: %d seconds)")
+                % (anc_date.as_unix_epoch() - desc_date.as_unix_epoch()));
+              diff_sum += anc_date.as_unix_epoch() -
+                          desc_date.as_unix_epoch();
+              incorrect++;
+            }
+        }
+      else
+        missing++;
+    }
+
+  form =
+    F("timestamp correctness between revisions\n"
+      "  correct dates   : %s edges\n"
+      "  equal dates     : %s edges\n"
+      "  incorrect dates : %s edges\n"
+      "  based on root   : %s edges\n"
+      "  missing date(s) : %s edges\n"
+      "\n"
+      "timestamp differences between revisions:\n"
+      "  mean            : %d sec\n"
+      "  min             : %d sec\n"
+      "  max             : %d sec\n"
+      "\n"
+      "  1st percentile  : %s sec\n"
+      "  5th percentile  : %s sec\n"
+      "  10th percentile : %s sec\n"
+      "  25th percentile : %s sec\n"
+      "  50th percentile : %s sec\n"
+      "  75th percentile : %s sec\n"
+      "  90th percentile : %s sec\n"
+      "  95th percentile : %s sec\n"
+      "  99th percentile : %s sec\n"
+      );
+
+  form = form % correct % equal % incorrect % root_anc % missing;
+
+  // sort, so that we can get percentile values
+  sort(diffs.begin(), diffs.end());
+
+  // calculate mean time difference, output that, min and max
+  s64 mean = accumulate(diffs.begin(), diffs.end(), 0);
+  mean /= diffs.size();
+  s64 median = *(diffs.begin() + diffs.size()/2);
+  form = form % mean % *diffs.begin() % *diffs.rbegin()
+    % *(diffs.begin() + int(diffs.size() * 0.01))
+    % *(diffs.begin() + int(diffs.size() * 0.05))
+    % *(diffs.begin() + int(diffs.size() * 0.10))
+    % *(diffs.begin() + int(diffs.size() * 0.25))
+    % *(diffs.begin() + int(diffs.size() * 0.50))
+    % *(diffs.begin() + int(diffs.size() * 0.75))
+    % *(diffs.begin() + int(diffs.size() * 0.90))
+    % *(diffs.begin() + int(diffs.size() * 0.95))
+    % *(diffs.begin() + int(diffs.size() * 0.99));
+
+  // output the string, with some newlines out of translation
+  out << '\n' << '\n' << form.str() << '\n';
 }
 
 void
============================================================
--- database.hh	40e06a31c4d18cf50a9a3f3f46bb2d14df06fe68
+++ database.hh	31ba75343ca21813eb814b814d6576440f4f0cfc
@@ -380,7 +380,7 @@ public:
   void debug(std::string const & sql, std::ostream & out);
   void dump(std::ostream &);
   void load(std::istream &);
-  void info(std::ostream &);
+  void info(std::ostream &, bool analyze);
   void version(std::ostream &);
   void migrate(key_store &);
   void test_migration_step(key_store &, std::string const &);