High Availability (HA)

PI OLEDB Enterprise is built with the AF SDK and therefore supports connection failover to servers in a PI collective.

If a server connection becomes unavailable, SQL statements that are in progress may fail. Whether they fail depends on many factors, such as which tables are involved and whether the failover is fast enough so that the AF SDK method calls do not time out, and whether the statement execution is in the midst of an AF SDK call or between AF SDK calls. It is important to note that there is no guarantee for a successful execution, which means that the OLE DB consumer application needs to implement proper error handling and possible retry attempts.

If no SQL statements are in progress when a server connection fails and the automatic transition to another collective member occurs, the user or application may notice a longer execution time, or timeout, for the next statement executed. To avoid this timeout, command timeout values may be increased for HA connections.

Note: High Availability (HA) support is based on AF SDK functionality. For further details, see the topic AF High Availability Using an AF Collective in the Overview Guide, available at the OSIsoft Customer Portal.