Session Analysis
Session Analysis (SessionAnalysis) measures the quality of each user visit from the session dimension, reporting bounce rate, session duration percentiles, and session depth. It corresponds to the backend AnalyticsService.SessionAnalysis.
1. What Questions It Answers
- How high is the bounce rate (users who view a single page and leave)?
- How long does a session last on average? What are the P50 / P90 durations?
- What is the session depth (events per session)? Are users engaged or just skimming?
2. Key Metrics
| Metric | Meaning |
|---|---|
| Session count | session_count |
| Session users | unique_users (distinct) |
| Average duration | avg_duration_sec (seconds) |
| P50 / P90 duration | Session duration percentiles (seconds) |
| Bounce rate | bounce_rate (0-1, share of sessions containing only one event) |
| Session depth | avg_depth (events per session = total events / sessions) |
3. Backend API
gRPC: AnalyticsService.SessionAnalysis
| Field | Type | Description |
|---|---|---|
time_range | TimeRange | Analysis time range |
app_id | uint32 (optional) | Filter by app |
platform | string (optional) | Platform filter (empty = all) |
Response SessionAnalysisResponse: session_count / unique_users / avg_duration_sec / p50_duration_sec / p90_duration_sec / bounce_rate / avg_depth.
HTTP (admin proxy)
POST /admin/v1/analytics/session-analysis
Content-Type: application/json
{
"timeRange": { "startMs": 1718169600000, "endMs": 1718774399000 }
}
4. Data Source
Session data comes from sessions_fact (the session fact table), aggregated from events_fact by ETL:
- Session: a stretch of continuous user activity (aggregated by
session_id, split on timeout). - Duration: time difference between the first and last events in the session.
- Depth: number of events in the session.
- Bounce: the session contains only 1 event.
Session aggregation is maintained by offline ETL (
sql/doris/06_etl.sql) or materialized views and may lag by minutes.
5. Typical Scenarios
Landing page quality evaluation
Look at bounce_rate: a high bounce rate means the landing page fails to engage users (content mismatch, slow loading, poor guidance) — optimize the first screen.
User engagement
Look at avg_depth and p50_duration_sec: low depth / short duration means shallow visits; improve content stickiness and guidance.
Per-platform comparison
Query platform for web/ios/android separately and compare session quality across platforms to locate the one with the weakest experience.
6. Notes and Caveats
- Depends on session aggregation: session metrics come from
sessions_fact, which requires the ETL/materialized views to run normally; if the table is empty, check the ETL first. - Bounce rate basis: defined as "the share of sessions with only 1 event"; acceptable levels differ by product (content sites typically have higher bounce rates than tool sites).
- Percentiles are in seconds:
p50_duration_sec/p90_duration_secare in seconds. - Session splitting: sessions are defined by
session_id; the timeout rule affects session counts and durations (finer splitting → more, shorter sessions).