GSOC-304: ThingsBoard IoTDB 2.x Table Model Integration — Design and PoC

[PDGGK]

Hi,

I've been working on a design for GSOC-304 and wanted to share my progress publicly.

Design

The integration uses two tables in the IoTDB 2.x Table Model:

• A telemetry table (4 TAGs: tenant_id, entity_type, entity_id, key + 5 typed FIELD columns)
• An entity_attributes table (adding scope TAG for client/shared/server attributes)

This maps directly to ThingsBoard's TimeseriesDao, TimeseriesLatestDao, and AttributesDao interfaces.

PoC

Working proof of concept validated against IoTDB 2.0.5:

https://github.com/PDGGK/thingsboard-iotdb-table-poc

The PoC runs 12 verified steps with assertions covering:

• Multi-type Tablet writes (bool, long, double, string, JSON)
• Same-timestamp type-change detection + delete-then-insert fix
• SQL range queries, latest-value (ORDER BY time DESC LIMIT 1), and findAllLatest (N-parallel queries)
• Aggregation with date_bin() + COALESCE mixed-type promotion
• TTL-based retention via ALTER TABLE SET PROPERTIES
• Entity attributes table with scope-based filtering

All steps include assertions that verify expected behavior.

Prior contributions

• Merged: #17212 (Process resource leak fix)
• Open: #17180 (GROUP BY inclusive end time)
• 14 merged PRs total across 6 open-source projects

I've discussed the schema design with the mentor and incorporated feedback on the single-table vs per-entity-table tradeoff.

I also opened a cross-community discussion with the ThingsBoard project: thingsboard/thingsboard#15296

Happy to discuss the design with anyone interested.

Zihan Dai
GitHub: @PDGGK