[zzylol]

Repeated and related queries could rebuild work that another query already computes. This change adds the missing reuse candidates and a numerically safe search fallback for mixed repeat intervals.

Before this PR: duplicate exact percentiles were separate scalar aggregates; coarser groups missed inner range reductions; one-pane readers could not join longer chains; filtered SQL quantiles rebuilt their input; SQL count-ranked TopK lacked a raw-row heap. Direct pricing could reject mixed schedules on numerical-range guards and leave the search with a much more expensive plan.

After this PR:

• [Bug] Identical exact query-time aggregates are not shared across queries #922: identical scalar aggregates and identity-preserving TopK results share; different percentile ranks share their source window. Duplicate percentile cost is about 0.0780235/s, versus 0.0981873/s before; different ranks cost 0.0881873/s.
• [Bug] An exact coarser grouping does not roll up the finer exact result #923: rollups cross identical per-series reductions while preserving window/filter/function boundaries. Integer counts merge count states without float conversion. The original coarse-sum workload costs about 0.0066901/s; SQL count and inner-range sketch variants have regression coverage.
• [Bug] A nested shorter window of an exact sum does not reuse the newest panes of the longer window's chain #924: a one-pane reader can consume the newest pane of a longer chain. Original paired-window cost falls from 0.0082898/s to about 0.00415648/s; the SQL variant is covered too.
• [Bug] The same query at a longer repeat interval recomputes instead of reusing the shorter-interval result #925: bounded maintained-state proposals find shared plans across repeat intervals. If direct monetary coefficients remain unsupported, a structural proposal is priced by the full evaluator. Neither numerical guard is weakened and no restricted-model bound becomes a global bound. Original mixed-repeat cost falls from 0.0124000/s to about 0.0041495/s; SQL mixed repeats are covered.
• A filtered query (city = 'NYC') doesn't read its group from a grouped summary another query builds #902: a key-equality reader consumes an existing grouped quantile result. An at-most-one-row reduction preserves SQL's one NULL row for an absent group. Exact and KLL readouts retain their proper guarantees; predicates selecting multiple groups do not inherit a single quantile's rank bound. The original workload costs about 0.196309/s versus 0.372321/s before.
• SQL top-k by COUNT(*): sketch candidates are misplaced (per-host CMS/UnivMon, heap over exact counts); no CMS+heap over raw rows #886: raw-row CMS/CountSketch heaps use unit weights and absorb the inner count. Unsupported per-group SQL count-sketch realizations are explicitly pruned; exact counters remain. Heap compilation/execution is tested. Frequency bounds still do not certify TopK membership: the accuracy gate remains in force.

Key code interfaces added / modified: CSE eligibility; pane/rollup candidate rules; add_filtered_group_candidates; guarantee recomposition; PruneReason::NoRelationalCountSketchRealization; internal maintained-state and structural search seeds. No executor API changes.

Major algorithm changes: bounded maintained-state proposal search with evaluator-only structural fallback; reuse through identical per-series reductions; integer count-state rollups; filtered single-group quantile reads.

Validation: failing-first reproductions, focused production-planner regressions, executor checks for NULL/empty/grouped-count/raw-heap cases, negative accuracy and reuse-boundary tests, and search tests preserving full-domain bounds. 690 focused tests passed: asap-types --lib (211), asap-logical-asap-optimization --lib (231), asap-plan-selection --lib search:: (225), and the three integration targets identical_exact_queries, per_computation_candidates_sql, and sharing_issue_regressions (23). cargo fmt --all -- --check and cargo clippy --workspace --all-targets --all-features --locked -- -D warnings also passed. Bounded search results are incumbents, not claims of whole-workload optimality.

Fixes #922
Fixes #923
Fixes #924
Fixes #925
Fixes #902
Fixes #886

[zzylol]

Reviewed the implementation and regression coverage for #922, #923, #924, #925, #902 and #886. This is an author self-review, not independent approval.

Checked that filtered grouped quantile reuse preserves SQL empty/NULL behavior and restricts accuracy propagation to a single exact key; count rollups preserve integer states; raw-row heaps retain membership-accuracy rejection where no guarantee exists; restricted/structural search seeds are evaluated at actual cost and do not supply a global lower bound. Numerical safety thresholds remain unchanged.

The first CI run exposed CPU contention between concurrent wall-clock planning regressions. Commit acdccb8 serializes planning within each affected test binary without changing the 30-second budgets or cost assertions. Both binaries now pass with default libtest concurrency (14 tests), and formatting passes. Previous focused validation passed 690 tests and workspace clippy. Awaiting the new full CI run before merging.

[zzylol]

CI follow-up: all 12 sharing regressions passed on GitHub after isolating their planning budgets. The full run then reached an older filter-subquery composition test that assumed SQL count sketch choices were available. Those unsupported choices are deliberately pruned by this PR. Commit 3d634d3 uses a quantile subquery instead, preserving the multiple-choice substitution and approximate-input guarantee assertions. All 14 tests in stage1_logical_asap_optimization pass locally. Full CI is being rerun; no production behavior or numerical threshold changed in these follow-ups.

[zzylol]

Further CI coverage found nine legacy candidate-composition tests that depended on unsupported SQL Count CMS/UnivMon choices. ede27c6 updates SQL count assertions to require the exact accumulator and explicit NoRelationalCountSketchRealization reasons. Approximate composition tests now use executable KLL quantiles, retaining filter/HAVING placement, sizing, substitution, schema and guarantee assertions (including identity-only output alias projections).

Validation: all 266 logical-asap-optimization tests pass, all 376 plan-selection tests pass, and the changed package passes clippy with -D warnings. The latest GitHub format/lint check also passed. Full workspace CI remains pending.

[zzylol]

Review and validation complete for ede27c6. All checks passed: full Rust workspace tests, format/clippy, DAG viewer Python and Node tests, PromQL-only planner checks/tests, MetricsQL external dependency compatibility, vendored parser baseline, and PR title. CI: https://github.com/ProjectASAP/ASAPPlanner/actions/runs/40449306832

Merged via squash as ebfad9c. Verified #922, #923, #924, #925, #902 and #886 are all closed as completed.