SIMATIC WinCC Open Architecture Forum

Hello Forum,

I have a question regarding the NGA with PostgreSQL and segment switching.
( WinCC 3.20 P003)

I wanted to see how the segments work in NGA with PostgreSQL so I created a simple project for testing.
Legacy Standard Project, Single Server, SQLite, NGA with PostgreSQL

Problem steps:
1. I created an archive group with segment duration 2 hours. Added some datapoints and made some value changes so the segment gets created.
2. Directly after this I changed the segment duration to 1 hour.
3. The segment still showed the old duration of 2 hours and also did not automatically switch the segment after 1 hour (actually expected this).
4. Tried to manually switch the segment, but the buttons are disabled.
5. Looking at the default PostgreSQL profile "Allow manual segment switch" is not checked.

WinCC OA Assistant:Yes, you can perform a manual segment switch in NGA using a PostgreSQL database as the backend in WinCC OA.

I did try to find this information myself in the documentation but I only found this. Nothing specific to PostgreSQL.

Allows manual segment switch: Some databases (such as InfluxDB®) can only perform automatic segment switches.

6. I cannot modify the profile because it is currently used by a backend.
7. I cannot (temporarily) change the profile of the backend. Once a profile is selected for a backend it cannot be changed anymore (the dropdown-menu is disabled). I could not find this behaviour in the documentation.
(Stopping the database or unchecking the Active checkbox did not change this behaviour)

My questions are:
1. Should changing the segment time for a segment automatically adjust the current segment?
2 If not: How can we change it, if manually switching is not possible (e.g. accidentially set it to 1 year instead of 1 hour)?
3. How can we modify the settings of a profile or change the profile of a backend without deleting the backend first?
4. Can a PostgreSQL backend manually switch the segments? WinCC OA Assistant says yes but it also says this

In WinCC OA, NGA (Next Generation Archiving) does not support PostgreSQL as a backend for archiving.

Thanks in advance

BR
Dennis

1. No, changing the segment time does just effect the newly created segments
2. Its not something you can do easily. At the moment we do not support a way to change the segment duration of already created segments. The only way of changing this would be via your database but this is something which should be done by consultants and database experts of ours.
3. You should not need to change the profile of the backend (probably you mean from InfluxDB_singleDB to dual for redu?) but those should be automatically created when using a redundant server
4. No, I am not aware of a possible manual segment switch - but if its correlated to point 1. you could take into account to delete the whole backend and create a new one with the segment duration you want to have

Br, Herbert