I am using dedicated physical server pc for netxms server. Specs :
2 * Sockets with 12 Cores (total 48 cores with hyper threading enabled)
4* SSD Drive with raid,
128 GB Ram,
Centos 7,
Postgresql 9.6.3

Top Command result :
Tasks: 507 total,  3 running, 503 sleeping,  0 stopped,  1 zombie
%Cpu(s):  2.6 us,  3.3 sy,  0.0 ni, 92.4 id,  1.5 wa,  0.0 hi,  0.1 si,  0.0 st
KiB Mem : 13189904+total,  2368860 free,  6030832 used, 12349934+buff/cache
KiB Swap:  4194300 total,  4194300 free,        0 used. 11046916+avail Mem

  PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM    TIME+ COMMAND
15841 root      20  0 26.819g 2.455g  5564 S 238.9  2.0  2755:30 netxmsd
 4443 postgres  20  0 10.492g 905084 889572 R  31.6  0.7  0:58.43 postmaster
 7128 postgres  20  0 10.506g  61756  34000 R  9.6  0.0  0:00.29 postmaster

As you can see, OS is not swapping. And normally, everything is very vell. I can see line chart that has 8 lines and 60 secs data collection time with 30 day in 3-4 seconds.

Other Information about netxms server and pc is :

Database size : 116-120 GB

netxmsd: sh dbstats
SQL query counters:
  Total .......... 464511464
  SELECT ......... 108457658
  Non-SELECT ..... 356062135
  Long running ... 0
  Failed ......... 1
Background writer requests:
  DCI data ....... 122998830
  DCI raw data ... 123126498
  Others ......... 32500

netxmsd: sh stats
Total number of objects:    31872
Number of monitored nodes:  1601
Number of collectable DCIs:  33637

netxmsd: sh qu
Data collector                  : 0
DCI cache loader                : 0
Database writer                  : 0
Database writer (IData)          : 4
Database writer (raw DCI values) : 1
Event processor                  : 0
Node poller                      : 0
Syslog processing                : 0
Syslog writer                    : 0

netxmsd: sh watch
Thread                                          Interval Status
----------------------------------------------------------------------------
Item Poller                                      10      Running
Syncer Thread                                    30      Sleeping
Ad hoc scheduler                                5        Sleeping
Recurrent scheduler                              5        Sleeping
Poll Manager                                    5        Sleeping

I will send an other post to add more screen shots.

By the way, this timeout problem was not happening in netxms 2.0.8. It started when I upgraded to 2.1 from 2.0.8

Can you help me, please. Thanks.