Few doubts regarding Streaming data : 1. Pinot supports data ingestion via streaming (Kafka) or batch(Hadoop) process. is there any direct API available for pushing data into Pinot? 2. Does pinot have a segment compaction process like Hbase compaction? Creating a lot of small segments will not affect query performance?

There offline push is via http post. There isn’t a write api right now if that’s what you are asking.

Based on my understanding, Pinot Streaming Processor can pull data from Kafka, kinesis, etc. but Pinot doesn't have a rest layer that accepts data requests(POST) directly. is there any plan to support write REST API in the future?

We have discussed, but there's no concrete timeline right now. May I ask what's your use case that would need the write-api?