Add predownload functionality to Pinot #14686
Open
+2,211
−4
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feature
performance
#14592
Add a pre-download feature to enable "graceful" node replacement on Pinot. With this feature, during node replacement, admins would replace the old node (OD) to new node (NN) with the same instance id. Instead of bringing down the ON before starting up NN (which is required because there cannot be 2 nodes taking same helix id at the same time), admins could:
- pre-download fully succeed
- pre-download partially succeed but have retried enough times
- pre-download failed in non-retriable mode
- already waited for a max time period
With a successful pre-download, the Pinot node replacement could perform in the same way as a node restart. We could observe the downtime (referring to helix pending message values decrease to 0) reduce significantly.
(1h -> 10min in the attached case. Sometimes, it could be fully transparent if node load is not high.)