Jay-ju opened a new pull request, #66608:
URL: https://github.com/apache/doris/pull/66608
Ordinary Lance scans read every row of a fragment even when the query only
needs the first N. Lance applies its LIMIT after the scanner's own filter, so
we can forward the query LIMIT to each fragment scanner and let it stop early.
To stay correct we only push the LIMIT when all predicates are already
pushed into Lance (no residual Doris conjunct). Otherwise Doris still filters
the returned rows and an early truncation could drop valid results. The upper
LIMIT operator keeps enforcing the global bound across fragments, so per-split
truncation is always safe.
- thrift: add optional TLanceFileDesc.limit
- FE: set it in LanceScanNode.setScanParams only when hasLimit() and
conjuncts is empty; also surface it in explain output
- BE: forward it via lance_scanner_set_limit for ordinary scans (vector
search keeps its own top_k limit)
### What problem does this PR solve?
Issue Number: close #xxx
Related PR: #xxx
Problem Summary:
### Release note
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