Memory usage of OPCSystemsDatabase.exe Windows Service is high when data logging fails. Also the OPCSystemsService.exe when logging to CSV files and users open Excel or remote data logging services connect to the remote tags to be logged and a network failure occurs.

Go to Configure-Options-Data Buffering and enable data buffering to disk.

View the following video on how to setup data logging so there is no data loss on a network or database engine failure:

I need to log to a remote Oracle database engine or a database engine that is not included in the TNSNAMES.ORA file.

Use the following as the Database name:


As example for a system with a computer name GWDESK and the Oracle database name OPCDb:


How much memory on the hard disk is taken up when logging to SQL Server?

The following should be used as an aid in sizing database requirements.

The method used is to store 100 Tags each, of a few common data types for one hour at a 1 second continuous interval to separate tables. SQL Server 2005 Express was used to gather this information.

As always your final results may vary.

In SQL Server you can set the Database property under Options for Recovery model to Simple to reduce disk usage.

Boolean Data type table size

Rows: 3598

Reserved: 200 KB

Data: 152 KB

Index Size: 16 KB

Unused: 32 KB

Double data type table size

Rows: 3598

Reserved: 3272 KB

Data: 3200 KB

Index Size: 16 KB

Unused: 56 KB

Integer data type table size

Rows: 3598

Reserved: 1672 KB

Data: 1600 KB

Index Size: 16 KB

Unused: 56 KB

String data type table size (100 char / tag)

Rows: 3589

Reserved: 84752 KB

Data: 84552 KB

Index Size: 144 KB

Unused: 56 KB