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Posted to issues@impala.apache.org by "Quanlong Huang (Jira)" <ji...@apache.org> on 2026/09/24 08:38:00 UTC

[jira] [Created] (IMPALA-15415) Document the HBO features

Quanlong Huang created IMPALA-15415:
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             Summary: Document the HBO features
                 Key: IMPALA-15415
                 URL: https://issues.apache.org/jira/browse/IMPALA-15415
             Project: IMPALA
          Issue Type: Documentation
            Reporter: Quanlong Huang
            Assignee: Sanjana Malhotra


We need documents to explain the HBO feature and relative flags, query options, and observability updates.

Query options:
 * use_hbo_stats
 * store_hbo_stats

Flags:
 * hbo_similarity_threshold
 * hbo_max_runs_per_key
 * hbo_in_memory_backend_cache_size_bytes

Observability updates:
 * EXPLAIN output or query plan in the profile shows "from HBO" annotation if the cardinality is read from HBO cache.
 * IMPALA-15236 extends this to add more details

HBO is still an experimental feature and is working in progress. But it'd be nice to document it in the 5.0 release.



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