Xiaobing

Allow a server to host segments on multi storage tiers

3

As of today, [a table with multi-tiers](https://docs.pinot.apache.org/operators/operating-pinot/tiered-storage#tier-config) has to use different server pools to support multi storage tiers, and relies on SegmentRelocator to move the segments among those server pools...

notify servers that need to move segments to new tiers via SegmentReloadMessage

6

This PR is part of the work to support multi-datadir for Pinot server as tracked by https://github.com/apache/pinot/issues/8843. Following up https://github.com/apache/pinot/pull/9598 and https://github.com/apache/pinot/pull/9306, this one has extended TableRebalancer to find out...

add SegmentContext to collect validDocIds bitmaps for many segments together

1

This PR adds SegmentContext used to collect segment related context before query execution. E.g. this makes it easier to collect validDocIds for many segments together, so that we can add...

For WBM flushes to pick largest memtable to flush

4

### Expected behavior When flushes due to `Write Buffer Manager` happen, try to pick the largest memtable (not flushed yet) to flush, instead of the one with smallest SeqNo. ###...