What is the difference w.r.t the comparison done by Altinity of clickhouse with timescale ? Clickhouse performed better there for the same test. What gives ?

If you are referring to this post: https://altinity.com/blog/clickhouse-for-time-series

That post was written in November 2018 - 3 years ago - when TimescaleDB was barely 1.0.

A lot has changed since then:

1. TimescaleDB launched native columnar compression in 2019, which completely changed its story around storage footprint and query performance [0]

2. TimescaleDB has gotten much better

3. PostgreSQL has also gotten better (which in turn makes TimescaleDB better)

In fact, IIRC Altinity used and contributed ClickHouse to the TSBS [1], which is also what this newer benchmark uses as well

(Disclaimer: TimescaleDB co-founder)

[0] https://blog.timescale.com/blog/building-columnar-compressio...

[1] https://github.com/timescale/tsbs