Is it?

I thought BlinkDB was data warehousing on hdfs? I dont see any mention of inference-like features in the docs?

It's not similar. BlinkDB builds upon the work on sampling-driven approximate SQL query processing (an early project in that space was AQUA@Bell Labs), and extends it to cloud/HDFS setting.

Although some terms come up in both places (e.g., confidence bounds, noise, etc), BlinkDB and probabilistic databases are fundamentally different from each other (I have worked on both topics).