Release v1.7.8 — batch-mode pipelined self-time (#215 D1)#269
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…f-time (#215 D1) (#268) Joe's plan 5GQmlu6m7W has a Parallelism (Gather Streams) above a batch-mode zone of three operators: Compute Scalar (9ms) / Hash Match Aggregate (10,294ms) / Clustered Index Scan (13,761ms). The exchange itself has elapsed 21,177ms and was being reported with 21,168ms of self-time because GetEffectiveChildElapsedMs only subtracted the direct child (the 9ms Compute Scalar). Batch mode pipelines operators — each operator's elapsed is standalone wall time for that operator, not cumulative of descendants the way row mode is. So for a row-mode parent above a batch-mode subtree, the correct "effective child elapsed" is the sum across the whole batch pipeline, not just the direct child. New SumBatchSubtreeElapsedMs walks a contiguous batch-mode zone (stopping at Parallelism boundaries) and sums ActualElapsedMs. GetEffectiveChildElapsedMs now routes batch-mode children with actual stats through that helper. Result on 5GQmlu6m7W: Parallelism self-time goes from 21,168ms (~56% of statement) to 0ms (clamped — 21.177 - 24.064 is negative, matching Joe's math). No more bogus "Expensive Operator" warning on the gather-streams. Regression check: - c1-c5.sqlplan (serial row mode) — all warnings unchanged - 20260415_1.sqlplan (parallel batch-mode) — all wait benefits and operator warnings unchanged (the batch subtree rule only fires when computing self-time of a row-mode parent above a batch child) D2 (unhelpful CXPACKET warning) was already addressed by v1.7.7's WaitStatsKnowledge content strip — the CXPACKET item now shows only the raw wait ms/count, no speculative fix text. Joe's deeper concern about CXPACKET double-counting other waits is a separate future refinement. Version bump 1.7.7 -> 1.7.8. Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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Summary
Fix for Joe's #215 D1: Parallelism (Gather Streams) over a batch-mode zone was reporting bogus 21s self-time. Batch-mode operators pipeline, so the correct self-time subtracts sum across the batch subtree, not just the direct child. On Joe's plan 5GQmlu6m7W, Parallelism self goes from 21,168ms to 0ms (matches his
21.177 − 0.009 − 10.294 − 13.761exactly).See PR #268.
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