Problems creating virtual feed after update

I recently updated the emoncms software with the last version and since then I’m not able to create a virtual feed to sum three powers for instance.

Any chance to correct this ?

Hi, can you tell us what system you are running please (EmonPi, EmonSD, self install etc)? Pasting the information from the admin page
will help us help you :smile: .

I’m using a raspberry pi 3 b where I’m put the image: emonSD-26Oct17 on it
I had some issues that without any reason after few days I have to restart the raspberry to continue to log feeds. At that time it was okay as I just wanted to see my consumption. I will in the futur have sonar panel and so I’m was looking to have a more stable version. This is why I update the software revision:
I’ve recently updated with this version:

emonSD-30Oct18 (Stable)

Since then it’s working well (1 week now) but I’m not able to sum the power as I’ve done it in the previous version.
When I try to create a virtual feed I’ve the same error @Neil see.

Have you run an update since you created the image?

If you post the information from the admin screen like I asked, it would help. Just click on the button and paste into a message - nothing else needed.

I see this problem too. Create a virtual feed. Click on the spanner. Select any (real) feed to use as the first item, make sure it’s set to ‘Source Feed’, click on ‘Changed, press to save’ and the error comes up.

ERROR: Could not save processlist. Cannot use virtual feed as source

Server Information
emonhub Active Running
mqtt_input Active Running
feedwriter Active Running - sleep 60s
service-runner Active Running
emonPiLCD Active Exited
redis-server Active Running
mosquitto Active Running
Emoncms Version low-write 9.9.8
Modules Administration : App v1.2.0 : Backup v1.1.5 : EmonHub Config v1.0.0 : Dashboard v1.3.1 : Device v1.2.0 : EventProcesses : Feed : Graph v1.2.1 : Input : Postprocess v1.0.0 : CoreProcess : Schedule : Network Setup v1.0.0 : sync : Time : User : Visualisation : WiFi v1.3.0
Git URL: GitHub - emoncms/emoncms: Web-app for processing, logging and visualising energy, temperature and other environmental data : Branch: * stable : Describe: 9.9.8-4-gd0db7a57
Server OS Linux 4.14.71-v7+
Host emonpi : emonpi : (
Date 2019-04-03 19:47:40 UTC
Uptime 19:47:40 up 18 days, 10:09, 2 users, load average: 0.02, 0.10, 0.10
HTTP Server Apache/2.4.25 (Raspbian) HTTP/1.1 CGI/1.1 80
MySQL Version 5.5.5-10.1.23-MariaDB-9+deb9u1
Host (
Date 2019-04-03 19:47:39 (UTC 00:00‌​)
Stats Uptime: 1592658 Threads: 3 Questions: 557160 Slow queries: 0 Opens: 33 Flush tables: 1 Open tables: 21 Queries per second avg: 0.349
Redis Version 3.2.6
Host localhost:6379 (
Uptime 17 days
MQTT Server Version Mosquitto 1.4.10
Host localhost:1883 (
Pi Model Raspberry Pi 3 Model B+ Rev 1.3 - 1 GB (Sony UK)
SoC Broadcom BCM2835
Serial num. 6FD53142
Temperature CPU: 53.69°C - GPU: 53.7’C
Release emonSD-30Oct18
Memory RAM Used: 18.54% Total: 976.74 MB Used: 181.13 MB Free: 795.61 MB
Swap Used: 0.00% Total: 100 MB Used: 0 B Free: 100 MB
Disk Mount Stats
/ Used: 39.87% Total: 3.81 GB Used: 1.52 GB Free: 2.11 GB
/boot Used: 51.69% Total: 42.52 MB Used: 21.98 MB Free: 20.54 MB
/home/pi/data Used: 1.76% Total: 10.32 GB Used: 185.41 MB Free: 9.61 GB
PHP Version 7.0.30-0+deb9u1 (Zend Version 3.0.0)
Modules apache2handler : calendar v7.0.30-0+deb9u1 : Core v7.0.30-0+deb9u1 : ctype v7.0.30-0+deb9u1 : curl v7.0.30-0+deb9u1 : date v7.0.30-0+deb9u1 : dom v20031129 : exif v7.0.30-0+deb9u1 : fileinfo v1.0.5 : filter v7.0.30-0+deb9u1 : ftp v7.0.30-0+deb9u1 : gd v7.0.30-0+deb9u1 : gettext v7.0.30-0+deb9u1 : hash v1.0 : iconv v7.0.30-0+deb9u1 : igbinary v2.0.1 : json v1.4.0 : libxml v7.0.30-0+deb9u1 : mbstring v7.0.30-0+deb9u1 : mcrypt v7.0.30-0+deb9u1 : mosquitto v0.4.0 : mysqli v7.0.30-0+deb9u1 : mysqlnd vmysqlnd 5.0.12-dev - 20150407 - $Id: b5c5906d452ec590732a93b051f3827e02749b83 $ : openssl v7.0.30-0+deb9u1 : pcre v7.0.30-0+deb9u1 : PDO v7.0.30-0+deb9u1 : pdo_mysql v7.0.30-0+deb9u1 : Phar v2.0.2 : posix v7.0.30-0+deb9u1 : readline v7.0.30-0+deb9u1 : redis v4.1.1 : Reflection v7.0.30-0+deb9u1 : session v7.0.30-0+deb9u1 : shmop v7.0.30-0+deb9u1 : SimpleXML v7.0.30-0+deb9u1 : sockets v7.0.30-0+deb9u1 : SPL v7.0.30-0+deb9u1 : standard v7.0.30-0+deb9u1 : sysvmsg v7.0.30-0+deb9u1 : sysvsem v7.0.30-0+deb9u1 : sysvshm v7.0.30-0+deb9u1 : tokenizer v7.0.30-0+deb9u1 : wddx v7.0.30-0+deb9u1 : xml v7.0.30-0+deb9u1 : xmlreader v7.0.30-0+deb9u1 : xmlwriter v7.0.30-0+deb9u1 : xsl v7.0.30-0+deb9u1 : Zend OPcache v7.0.30-0+deb9u1 : zlib v7.0.30-0+deb9u1
Client Information

Can you raise an issue on Github and reference it to here please.

I have had a look and proposed a solution PR @TrystanLea @glyn.hudson @Gwil.

1 Like

Thanks I will review this and update soon

1 Like