[jdbc.mysql] First two hours of any chart always flat

[thinkfat]

When adding any chart to the sitemap (classic ui), the first two hours are always a flat line. Doesn't seem to be an issue with persistence, if I switch to a longer period, the data is there and displayed. Just for each chart, not depending on displayed period, first two hours display a flat line. For hourly charts, of course the trace is then entirely flat.

I use the mysql persistence. No other persistence services enabled.

How to reproduce:
Every chart in a sitemap is affected. For example:
"Chart item=SomeNumberItem period=h refresh=30000" should produce a flat line.

I'm using openhab2 with docker, using the following docker file:

version: '2.2'

volumes:
    db:

services:
  db:
    image: mariadb
    command: --transaction-isolation=READ-COMMITTED --binlog-format=ROW
    restart: always
    volumes:
      - db:/var/lib/mysql
    environment:
      - MYSQL_USER=openhab
      - MYSQL_DATABASE=OpenHAB
      - MYSQL_ROOT_PASSWORD=XXX
      - MYSQL_PASSWORD=XXX

  knxd:
    image: "welteki/knxd:latest"
    restart: always
    network_mode: host
    command: knxd -D -R -T -S -e 0.0.1 -E 0.0.2:32 -u /tmp/knxd --send-delay=30 -b ipt:192.168.2.101

  openhab:
    image: "openhab/openhab:latest-debian"
    restart: always
    volumes:
      - "/etc/localtime:/etc/localtime:ro"
      - "/share/Container-Data/openhab/addons:/openhab/addons"
      - "/share/Container-Data/openhab/conf:/openhab/conf"
      - "/share/Container-Data/openhab/userdata:/openhab/userdata"
    environment:
      OPENHAB_HTTP_PORT: "8080"
      OPENHAB_HTTPS_PORT: "8443"
      EXTRA_JAVA_OPTS: "-Duser.timezone=Europe/Berlin"
    ports:
      - "2080:8080"
      - "2443:8443"
      - "2101:8101"
    links:
      - db

[CSchlipp]

I noticed the same quite some time ago, but didn't investigate further.
Whenever there's an offset of 1-2h, this tends to be some kind of timezone problem. The DB entries (at least in my case) are stored with UTC time, guess that's not correctly converted to the local timezone when creating the graphs...

[thinkfat]

That sounds like a plausible explanation. Is there any way I could check this?

[thinkfat]

Ok, well, yes. The container the database is running in has timezone UTC. OpenHAB container is on CEST. The mysql.cfg has "localtime=true", though. Should that not work around the difference?

[DiKaY1969]

I can confirm the problem too.

Unfortunately, the charts only show a static value in the period of 1 hour and not a trend! From a period of 4 hours and higher, the course is displayed correctly in the chart. This is also the case in the HabPanel's chart widget. I have not given a range but the course of the current hour should be given. I use mysql as a database. The time stamps of the data records are entered correctly.

Dierk