i2pplus

JRobin (jrobin/)

Fork of the RRD4J library (Round-Robin Database for Java) for efficient time-series data storage and graphing. Used for router statistics in the console.

What is Round-Robin Database?

RRD uses fixed-size databases that store data at regular intervals. Older data is automatically consolidated or discarded as new data arrives, ensuring:

• Constant storage - No growth over time
• Efficient queries - Pre-aggregated data at multiple resolutions
• Graph-ready - Built-in graphing from consolidated data

How I2P Uses It

Router statistics ( bandwidth, peer count, tunnel usage) are logged at regular intervals. The console then graphs these:

Resolution    Storage    Retention (days)
-----------------------------------------
  1 min        ~400B      2 days
  5 min        ~400B     10 days  
  1 hour       ~400B     25 days
  1 day        ~400B    >1 year

Data Consolidation

When moving between resolutions, RRD applies functions:

• AVERAGE - Mean of values
• MAX / MIN - Peak values
• LAST - Most recent value

This preserves both average behavior and peaks (important for bandwidth).

Key Classes

Class	Purpose
RrdDb	Database, holds datasources
RrdDef	Database definition
Sampler	Insert values
Graph	Render to image

Packages

• org.rrd4j.core - Database engine
• org.rrd4j.graph - Graph rendering
• org.rrd4j.data - Data manipulation and consolidation

Building

# Gradle
./gradlew :apps:jrobin:jar

# Ant (from repo root)
ant buildJrobin