Learn about topology testing and metrics
- Last UpdatedJun 09, 2025
- 2 minute read
- PI System
- PI Server 2024 R2
- PI Server
Topologies are tested under both normal and taxing conditions:
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"Normal" operating conditions: The everyday, 24/7, run-and-maintain system behavior
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"Taxing" conditions: System recovery after planned and unplanned outages, varying downtime recovery periods, automatic and manual backfills, behavior during cache rebuilds, as well as other conditions.
Testing under these conditions is done to ensure that hardware resources are sized correctly.
Performance envelope metrics
Performance envelope metrics are used to provide a system-wide, event-per-second rating that a topology is expected to sustain without taxing the specified hardware.
The following system components are factored in when calculating a topology's specific performance envelope or event-per-second rating:
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A set hardware configuration
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The latest released version of PI software
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Product installation requirements
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Product configuration and tuning settings
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The target, event-per-second rating
What do the metrics represent?
Performance envelope metrics are the recommended "bounds" for the system given the hardware shown in each topology's overview diagram.
The following table contains definitions for each of these metrics.
|
Topology performance metric |
Description |
|---|---|
|
Inbound data rate (events/sec) |
This is the maximum rate of all raw data coming into the system from all data sources per second. |
|
Archive data rate (events/sec) |
This is the maximum rate of archived events after compression has been applied per second. |
|
Analysis evaluation rate (evals/sec) |
This is the maximum rate of AF analytics evaluations per second. |
|
Event Frame (EF) generation rate (EFs/day) |
This is the maximum rate of event frames generated per day. These event frames have been generated by Asset Analytics. |
|
Notification rate (not/min) |
This is the maximum rate of notifications generated per minute. |
|
PI Vision Simultaneous Users |
This is the maximum amount of simultaneous users accessing PI Vision displays. This metric was designed with each user being able to load a display in under a minute. |
|
PI Web API Recorded Data Rate (events/sec) |
This is the maximum expected rate of recorded (uncompressed) data that was retrieved by PI Web API per second. |
|
PI SQL recorded data rate (events/sec) |
This is the maximum expected rate of recorded (uncompressed) data that was retrieved by PI SQL per second. Our testing utilizes PI JDBC with RTQP to perform the data retrieval. |
|
AF SDK recorded data rate (events/sec) |
This is the maximum expected rate of recorded (uncompressed) data that was retrieved by a custom AF SDK application per second. |