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Topic starter
Hello all,
I need your recommendation for DataBase.
We are creating a project together with Dream Report and in the dream report we need to display the trend along with the data table every second, an example is in the attachment.
In PcVue we have 700 variables that we have to record every second.
If I set a period of 1 second for each variable, I get breaks in the recording and I get an incorrect report in the Dream Report.
What to do in such a situation? How many variables can be written in 1 second? How to organize database and table?
Posted : 12/09/2022 3:31 pm
Hi Roman,
HDS overflow indicates that PcVue is recording faster than the SQL Server database can support.
That could be due to many different reasons. The main one is: Hardware (Hard disk mainly) of the compueter where SQL server is running.
By the way, keep in mind HDS is not recording with sampling, meaning if the data value/ts/status doesn't change then no point is recorded (cf archiving training module).
However, there is a 'sampling' setting but it is general, meaning for ALL trends.
Nico
Posted : 13/09/2022 8:48 pm
Topic starter
If I set Force one record per period, then I record a trend depending on the period, right?(at attachment the picture)
Do I understand correctly that PcVue does not affect this time? affected by hardware?
how can i check this and provide to the customer?
he needs to write 700 variables in 1 second, if I set it like that, then we have data loss every 2-3 minutes.
Posted : 13/09/2022 9:21 pm
Hello Roman,
700 events per second is not a big value for a local database situated on a SDD.
From the traces you sent us I estimated the performance to ~100 events recorded per second on this project.
Few questions, to understand more about the configured archives :
- Is it a local or a network database instance? Network can highly impact hds performance.
- What physical disks are used for PcVue and for the database ?
- Is the SQL Server instance used for other things than PcVue archiving ?
- Are there trigger set on the database ?
Also, can you provide some hds trace with the performance flag set ? put it only for a minute, remove the flag and send us Hds.log file.
Best regards,
Kévin
Posted : 13/09/2022 9:36 pm
Yes Roman, that's the Setting I was talking about. Using this one will force PcVue to record every 1s for all trends of your project.
Note that's a bad idea to do that but, we know that some software request this mode as a requirement.
But, if you are using Dream Report, you don't need to do that as, if I am not mistaken, it is acting like our Data export feature: Doing the sampling by itself if points are missing.
Thank you Kevin or your answer.
Nico
PS: Could you please change the title to something less generic than only 'HDS'?
Posted : 13/09/2022 9:51 pm