Why it matters

LLAP is Hive's interactive path. Understanding shapes low-latency Hive.

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The architecture

LLAP daemons: long-running JVMs on cluster nodes.

In-memory cache: shared across queries.

Query fragments run in daemons.

LLAP architectureLong-lived daemonson cluster nodesShared cachehot data in RAMFragment executionin daemonFalls back to Tez containers for queries not fitting LLAP model
LLAP components.
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How it works end to end

Cache: columnar cache with LRU eviction. Shared across queries + users.

Fault tolerance: query re-run on daemon death.

Integration: Tez uses LLAP for supported queries; falls back to containers.