perf: optimize was_applied fast path for known LWT statements (~1.5us, 1.1x speedup)#797
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mykaul wants to merge 2 commits intoscylladb:masterfrom
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perf: optimize was_applied fast path for known LWT statements (~1.5us, 1.1x speedup)#797mykaul wants to merge 2 commits intoscylladb:masterfrom
mykaul wants to merge 2 commits intoscylladb:masterfrom
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Add a fast path in ResultSet.was_applied that skips batch detection (isinstance checks + regex match) when the query has a known LWT status from the server PREPARE response. For BoundStatement queries where is_lwt() returns True, the batch_regex match on the query string is entirely avoided. This benefits the most common LWT use case: prepared INSERT/UPDATE IF statements executed via BoundStatement, where the driver already knows from the PREPARE response whether the statement is an LWT. The slow path (isinstance + regex) is preserved for: - BatchStatement queries (detected via isinstance) - SimpleStatement batch queries (detected via regex) - Any query where is_lwt() returns False Also adds explicit tests for the fast path, non-LWT fallback, and BatchStatement handling in was_applied. Part of: scylladb#751
Benchmark shows ~1.1x speedup for known-LWT fast path vs regex batch detection slow path.
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Summary
ResultSet.was_appliedfor statements wherequery.is_lwt()is True (BoundStatement/PreparedStatement)batch_regex.match()call andisinstance(query, BatchStatement)check for the common single-LWT caseBenchmark
Measured with
min()oftimeit.repeat(repeat=7, number=200_000)on a quiet machine (load <1).Savings: 612 ns/call
Tests
test_was_applied_lwt_fast_path,test_was_applied_non_lwt_fallback,test_was_applied_batch_statementtest_was_appliedto use explicit non-LWT query to exercise the slow (regex) path