shard: disable double flush and improve kmod vm

cpp/core/LogsDB.cpp

@@ -1591,10 +1591,10 @@ public:
 
     void flush(bool sync) {
         ROCKS_DB_CHECKED(_db->FlushWAL(sync));
-        _maybeLogStatus();
     }
 
     void processIncomingMessages(std::vector<LogsDBRequest>& requests, std::vector<LogsDBResponse>& responses) {
+        _maybeLogStatus();
         for(auto& resp : responses) {
             auto request = _reqResp.getRequest(resp.header.requestId);
             if (request == nullptr) {

cpp/shard/Shard.cpp

@@ -892,7 +892,8 @@ public:
             ALWAYS_ASSERT(_inFlightEntries.size() == LogsDB::IN_FLIGHT_APPEND_WINDOW);
         }
         _shared.shardDB.flush(true);
-        _logsDB->flush(true);
+        // not needed as we just flushed and apparently it does actually flush again
+        // _logsDB->flush(true);
 
         sendMessages();
     }