Implement COMMAND-STATS to expose total number of reads/writes since startup

src/Commands.cc

@@ -35,6 +35,7 @@ struct cmdMapInit {
     redis_cmd_map["debug"] = {RedisCommand::DEBUG, CommandType::CONTROL};
     redis_cmd_map["monitor"] = {RedisCommand::MONITOR, CommandType::CONTROL};
     redis_cmd_map["client_id"] = {RedisCommand::CLIENT_ID, CommandType::CONTROL};
+    redis_cmd_map["command_stats"] = {RedisCommand::COMMAND_STATS, CommandType::CONTROL};
 
     redis_cmd_map["auth"] = {RedisCommand::AUTH, CommandType::AUTHENTICATION};
     redis_cmd_map["hmac_auth_generate_challenge"] = {RedisCommand::HMAC_AUTH_GENERATE_CHALLENGE, CommandType::AUTHENTICATION};

src/Commands.hh

@@ -35,6 +35,7 @@ enum class RedisCommand {
   DEBUG,
   MONITOR,
   CLIENT_ID,
+  COMMAND_STATS,
 
   FLUSHALL,
 

src/Formatter.cc

@@ -27,6 +27,7 @@
 #include "Formatter.hh"
 #include "redis/ArrayResponseBuilder.hh"
 #include "redis/Transaction.hh"
+#include "utils/Statistics.hh"
 using namespace quarkdb;
 
 RedisEncodedResponse Formatter::moved(int64_t shardId, const RaftServer &location) {
@@ -191,6 +192,14 @@ RedisEncodedResponse Formatter::multiply(const RedisEncodedResponse &resp, size_
   return RedisEncodedResponse(ss.str());
 }
 
+RedisEncodedResponse Formatter::stats(const Statistics &stats) {
+  std::vector<std::string> arr;
+  arr.emplace_back(SSTR("TOTAL-READS " << stats.reads));
+  arr.emplace_back(SSTR("TOTAL-WRITES " << stats.writes));
+  arr.emplace_back(SSTR("TOTAL-BATCHES " << stats.batches));
+  return statusVector(arr);
+}
+
 RedisEncodedResponse Formatter::subscribe(std::string_view channel, size_t active) {
   return strstrint("subscribe", channel, active);
 }

src/Formatter.hh

@@ -32,6 +32,7 @@ namespace quarkdb {
 
 struct RaftEntry;
 class RedisRequest;
+struct Statistics;
 
 class Formatter {
 public:
@@ -64,6 +65,7 @@ public:
   static RedisEncodedResponse redisRequest(const RedisRequest &req);
 
   static RedisEncodedResponse multiply(const RedisEncodedResponse &resp, size_t factor);
+  static RedisEncodedResponse stats(const Statistics &stats);
 
 private:
   static RedisEncodedResponse strstrint(std::string_view str1, std::string_view str2, int num);

src/Shard.cc

@@ -220,6 +220,15 @@ LinkStatus Shard::dispatch(Connection *conn, RedisRequest &req) {
 
       return conn->status(ss.str());
     }
+    case RedisCommand::COMMAND_STATS: {
+      if(req.size() != 1) return conn->errArgs(req[0]);
+      InFlightRegistration registration(inFlightTracker);
+      if(!registration.ok()) {
+        return conn->err("unavailable");
+      }
+
+      return conn->raw(Formatter::stats(stateMachine->commandStats()));
+    }
     default: {
       if(req.getCommandType() == CommandType::QUARKDB) {
         qdb_critical("Unable to dispatch command '" << req[0] << "' of type QUARKDB");

src/StateMachine.cc

@@ -1786,12 +1786,18 @@ std::string StateMachine::statistics() {
   return stats;
 }
 
+//------------------------------------------------------------------------------
+// Get level stats
+//------------------------------------------------------------------------------
 std::string StateMachine::levelStats() {
   std::string stats;
   db->GetProperty(rocksdb::DB::Properties::kLevelStats, &stats);
   return stats;
 }
 
+//------------------------------------------------------------------------------
+// Get compression stats
+//------------------------------------------------------------------------------
 std::vector<std::string> StateMachine::compressionStats() {
   std::vector<std::string> results;
 
@@ -1804,6 +1810,13 @@ std::vector<std::string> StateMachine::compressionStats() {
   return results;
 }
 
+//------------------------------------------------------------------------------
+// Get command stats
+//------------------------------------------------------------------------------
+Statistics StateMachine::commandStats() {
+  return requestCounter.getOverallStats();
+}
+
 rocksdb::Status StateMachine::noop(LogIndex index) {
   StagingArea stagingArea(*this);
   return stagingArea.commit(index);

src/StateMachine.hh

@@ -243,6 +243,11 @@ public:
   //----------------------------------------------------------------------------
   std::vector<std::string> compressionStats();
 
+  //----------------------------------------------------------------------------
+  // Get command stats
+  //----------------------------------------------------------------------------
+  Statistics commandStats();
+
   bool inBulkLoad() const {
     return bulkLoad;
   }

src/utils/RequestCounter.cc

@@ -65,6 +65,10 @@ void RequestCounter::setReportingStatus(bool val) {
   activated = val;
 }
 
+Statistics RequestCounter::getOverallStats() {
+  return aggregator.getOverallStats();
+}
+
 void RequestCounter::mainThread(ThreadAssistant &assistant) {
   while(!assistant.terminationRequested()) {
 

src/utils/RequestCounter.hh

@@ -48,6 +48,8 @@ public:
 
   void setReportingStatus(bool val);
   void account(const RedisRequest &req);
+
+  Statistics getOverallStats();
 private:
   void account(const RedisRequest &req, Statistics *stats);