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History Queries

OIBus enables both real-time data streaming and historical data retrieval, allowing access to information from periods before your streaming setup was active.

Create a History Query​

Setup Options​

You can create history queries using:

  • New South/North connectors specifically for historical retrieval
  • Existing South/North connectors (all items will be copied)
Compatible Connectors

Only South connectors with historian capabilities support history queries, including:

  • OPC UA (HA mode)
  • OPC Classic (HDA mode)
  • MSSQL/SQL Server
  • PostgreSQL
  • Oracle
  • OSIsoft PI System™
  • Other temporal database connectors

History Query Main Settings​

Time Configuration​

  1. Start Time: Beginning of historical period (required)
  2. End Time: End of historical period (required)
SQL Connectors Requirement

For SQL-based connectors, you MUST include both time variables in your queries:

SELECT * FROM sensor_data
WHERE timestamp > @StartTime
AND timestamp <= @EndTime

Resilience Features​

Automatic Recovery​

  • Tracks maximum retrieved timestamp in local cache
  • Resumes from last position after connection failures
  • Maintains progress across restarts

Item Grouping​

  • Default: Items share the same maximum instant (better performance)
  • Max instant per item: Tracks each item separately (more precise)
When to Use Per-Item Tracking (OPCUA, OPC, PI)

Use "Max instant per item" when:

  • Data points update at different frequencies
  • Source system doesn't guarantee synchronous writes
  • You need individual progress tracking for each item

Note: This creates separate queries per item which may increase server load

Running a Query​

Execution Controls​

Start or pause queries from:

  • Editing page
  • List page
  • Display page

Monitoring​

The display page shows:

  • Current progress
  • Query status
  • Items processed
  • Estimated completion
Important Note

Any modifications to:

  • Added/removed items
  • Updated configurations
  • Time range changes

will restart the query from the original start time.