Poller output not empty all the time #4687
Description
I'm getting this stuff all the time:
2022/04/09 01:57:51 - SYSTEM STATS: Time:169.0462 Method:cmd.php Processes:1 Threads:1 Hosts:177 HostsPerProcess:177 DataSources:5235 RRDsProcessed:3035
2022/04/09 01:55:02 - POLLER: Poller[Main Poller] PID[23758] WARNING: Poller Output Table not Empty. Issues: 2, DS[SW_F2 - Traffic - 1:49 (Up) [ISC_B-F1_1]] Graphs[SW_F2 - Traffic - 1:49 (Up) [ISC_B-F1_1] ]
The graphs seem to be rendered ok, but I still get an alert email all the time.
Looking at the actual table it looks like this:
+---------------+-------------+---------------------+----------------+
| local_data_id | rrd_name | time | output |
+---------------+-------------+---------------------+----------------+
| 6482 | traffic_in | 2022-04-09 01:45:42 | 41487596159437 |
| 6482 | traffic_in | 2022-04-09 01:50:45 | 41488856327543 |
| 6482 | traffic_in | 2022-04-09 01:55:51 | 41490182632144 |
| 6482 | traffic_out | 2022-04-09 01:47:06 | 33628854252 |
| 6482 | traffic_out | 2022-04-09 01:52:12 | 33629294595 |
| 6482 | traffic_out | 2022-04-09 01:57:18 | 33629750504 |
+---------------+-------------+---------------------+----------------+
local_data_id 6482 is just a random port of some switch.
As a matter of fact, previously, "Poller Output Table not Empty" was due to id 6481. So I identified that graph and datasource and deleted both and recreated them. The new one got id 8000...something and works fine. But after I had done that, it started complaining about id 6482 (6481 +1). There seems to be something magic going on at that point.
What does that mean? What could be wrong here?
Cacti 1.2.20
Mainly using "SNMP - Interface Statistics" Data Query
There are no PHP errors that I could find.
PS I tried to dig into the details of what Cacti does and there is for example an image missing on the documentation page that could be helpful https://docs.cacti.net/Principles-of-Operation.md -> Principles of Operation. https://github.com/Cacti/documentation/blob/develop/images/principles-of-operation.png seems to be just empty.
