diff --git a/src/command_line.cc b/src/command_line.cc
index dfe9f78c..a395f66f 100644
--- a/src/command_line.cc
+++ b/src/command_line.cc
@@ -336,6 +336,7 @@ void LaunchStdinLoop(Config* config,
         case IpcId::CqueryBase:
         case IpcId::CqueryDerived:
         case IpcId::CqueryIndexFile:
+        case IpcId::CqueryRandom:
         case IpcId::CqueryWait: {
           queue->for_querydb.PushBack(std::move(message));
           break;
diff --git a/src/ipc.cc b/src/ipc.cc
index 495ad307..01029af8 100644
--- a/src/ipc.cc
+++ b/src/ipc.cc
@@ -86,6 +86,8 @@ const char* IpcIdToString(IpcId id) {
       return "$cquery/base";
     case IpcId::CqueryDerived:
       return "$cquery/derived";
+    case IpcId::CqueryRandom:
+      return "$cquery/random";
 
     case IpcId::Unknown:
       return "$unknown";
diff --git a/src/ipc.h b/src/ipc.h
index aaab0055..59d820ec 100644
--- a/src/ipc.h
+++ b/src/ipc.h
@@ -57,6 +57,7 @@ enum class IpcId : int {
   CqueryCallers,  // Show all callers of a function.
   CqueryBase,     // Show base types/method.
   CqueryDerived,  // Show all derived types/methods.
+  CqueryRandom,   // Show random definition.
 
   // Internal implementation detail.
   Unknown,
diff --git a/src/messages/cquery_random.cc b/src/messages/cquery_random.cc
new file mode 100644
index 00000000..029bfd1c
--- /dev/null
+++ b/src/messages/cquery_random.cc
@@ -0,0 +1,147 @@
+#include "message_handler.h"
+#include "query_utils.h"
+#include "queue_manager.h"
+
+#include <math.h>
+#include <stdlib.h>
+#include <numeric>
+
+namespace {
+struct Ipc_CqueryRandom : public RequestMessage<Ipc_CqueryRandom> {
+  const static IpcId kIpcId = IpcId::CqueryRandom;
+};
+MAKE_REFLECT_STRUCT(Ipc_CqueryRandom, id);
+REGISTER_IPC_MESSAGE(Ipc_CqueryRandom);
+
+const double kDeclWeight = 3;
+const double kDamping = 0.1;
+const double kAlpha = 0.3;
+
+template <typename Q>
+struct Kind;
+template <>
+struct Kind<QueryFunc> { static constexpr SymbolKind value = SymbolKind::Func; };
+template <>
+struct Kind<QueryType> { static constexpr SymbolKind value = SymbolKind::Type; };
+template <>
+struct Kind<QueryVar> { static constexpr SymbolKind value = SymbolKind::Var; };
+
+template <typename Q>
+void Add(const std::unordered_map<SymbolIdx, int>& sym2id,
+         std::vector<std::unordered_map<int, double>>& adj,
+         const std::vector<Id<Q>>& ids,
+         int n,
+         double w = 1) {
+  for (Id<Q> id : ids) {
+    auto it = sym2id.find(SymbolIdx{RawId(id), Kind<Q>::value});
+    if (it != sym2id.end())
+      adj[it->second][n] += w;
+  }
+}
+
+struct CqueryRandomHandler : BaseMessageHandler<Ipc_CqueryRandom> {
+  void Run(Ipc_CqueryRandom* request) override {
+    std::unordered_map<SymbolIdx, int> sym2id;
+    std::vector<SymbolIdx> syms;
+    int n = 0;
+
+    for (RawId i = 0; i < db->funcs.size(); i++)
+      if (db->funcs[i].def) {
+        syms.push_back(SymbolIdx{i, SymbolKind::Func});
+        sym2id[syms.back()] = n++;
+      }
+    for (RawId i = 0; i < db->types.size(); i++)
+      if (db->types[i].def) {
+        syms.push_back(SymbolIdx{i, SymbolKind::Type});
+        sym2id[syms.back()] = n++;
+      }
+    for (RawId i = 0; i < db->vars.size(); i++)
+      if (db->vars[i].def) {
+        syms.push_back(SymbolIdx{i, SymbolKind::Var});
+        sym2id[syms.back()] = n++;
+      }
+
+    std::vector<std::unordered_map<int, double>> adj(n);
+    auto add = [&](const std::vector<Use>& uses, double w) {
+      for (Use use : uses) {
+        auto it = sym2id.find(SymbolIdx{RawId(use.id), use.kind});
+        if (it != sym2id.end())
+          adj[it->second][n] += w;
+      }
+    };
+    n = 0;
+    for (QueryFunc& func : db->funcs)
+      if (func.def) {
+        add(func.declarations, kDeclWeight);
+        add(func.uses, 1);
+        Add(sym2id, adj, func.derived, n);
+        n++;
+      }
+    for (QueryType& type : db->types)
+      if (type.def) {
+        add(type.uses, 1);
+        Add(sym2id, adj, type.instances, n);
+        Add(sym2id, adj, type.def->funcs, n);
+        Add(sym2id, adj, type.def->types, n);
+        Add(sym2id, adj, type.def->vars, n);
+        n++;
+      }
+    for (QueryVar& var : db->vars)
+      if (var.def) {
+        add(var.declarations, kDeclWeight);
+        add(var.uses, 1);
+        n++;
+      }
+    for (int i = 0; i < n; i++) {
+      double sum = 0;
+      adj[i][i] += 1;
+      for (auto& it : adj[i])
+        sum += it.second;
+      for (auto& it : adj[i])
+        it.second = it.second / sum * (1 - kDamping);
+    }
+
+    std::vector<double> x(n, 1), y;
+    while (1) {
+      y.assign(n, kDamping);
+      for (int i = 0; i < n; i++)
+        for (auto& it : adj[i])
+          y[it.first] += x[i] * it.second;
+      double d = 0;
+      for (int i = 0; i < n; i++)
+        d = std::max(d, fabs(x[i] - y[i]));
+      if (d < 1e-5) break;
+      x.swap(y);
+    }
+
+    double sum = std::accumulate(x.begin(), x.end(), 0.), stdev = 0, offset = 0;
+    for (int i = 0; i < n; i++)
+      stdev += (x[i] - sum / n) * (x[i] - sum / n);
+    stdev = sqrt(stdev / n) * kAlpha;
+    for (int i = 0; i < n; i++)
+      offset = std::max(offset, x[i] / stdev);
+    sum = 0;
+    for (int i = 0; i < n; i++)
+      sum += x[i] = exp(x[i] / stdev - offset);
+
+    Out_LocationList out;
+    out.id = request->id;
+    double roulette = rand() / (RAND_MAX + 1.0) * sum;
+    sum = 0;
+    for (int i = 0; i < n; i++) {
+      sum += x[i];
+      if (sum >= roulette) {
+        Maybe<Use> use = GetDefinitionExtentOfSymbol(db, syms[i]);
+        if (!use)
+          continue;
+        optional<lsLocation> ls_loc = GetLsLocation(db, working_files, *use);
+        if (ls_loc)
+          out.result.push_back(*ls_loc);
+        break;
+      }
+    }
+    QueueManager::WriteStdout(IpcId::CqueryRandom, out);
+  }
+};
+REGISTER_MESSAGE_HANDLER(CqueryRandomHandler);
+}  // namespace
diff --git a/src/ntstring.h b/src/ntstring.h
index 3aa16687..0e6703de 100644
--- a/src/ntstring.h
+++ b/src/ntstring.h
@@ -35,13 +35,6 @@ class NTString {
     const char *p = strstr(c_str(), s);
     return p ? std::string::size_type(p - c_str()) : std::string::npos;
   }
-  size_type find(const char* s, size_type pos, size_type cnt) {
-    auto* p = (const char*)memmem(c_str() + pos, strlen(c_str()) - pos, s, cnt);
-    return p ? std::string::size_type(p - c_str()) : std::string::npos;
-  }
-  size_type find(std::string_view sv) {
-    return find(sv.data(), 0, sv.size());
-  }
 
   void operator=(std::string_view sv) {
     str = std::unique_ptr<char[]>(new char[sv.size() + 1]);