Hi,
In my development enviroment i am able to read data from HISTVAL table in WINCC OA, the problem arises when we try to read data from the client WINCC OA enviroment, they say the have their historic data configured so the SCADA does a Level 2 compression,
Could someone explain if this could affect somehow on reading data fron the HISTVAL value with a standar query like "Select * from histval", and if so, how could i solve this?
thx in advance.
Reading from SCADA compresion LVL2
- leoknipp
- Posts:2928
- Joined: Tue Aug 24, 2010 7:28 pm
Re: Reading from SCADA compresion LVL2
Hello,
the compression state of the archive files should not have an impact on the OLE DB functionality.
When the files are "compressed" only free (unused) entries are removed the files. This type of compression cannot be compared to the compression of files using a tool like "zip".
To test it in your system you can make a fileswitch and compress the older archive files using the "Actions" panel for the history database.
Best Regards
Leopold Knipp
Senior Support Specialist
the compression state of the archive files should not have an impact on the OLE DB functionality.
When the files are "compressed" only free (unused) entries are removed the files. This type of compression cannot be compared to the compression of files using a tool like "zip".
To test it in your system you can make a fileswitch and compress the older archive files using the "Actions" panel for the history database.
Best Regards
Leopold Knipp
Senior Support Specialist