Summary

16 iterative optimization loops on a data processing pipeline, reducing end-to-end response time from 1,829ms to 352ms (80.8%). Each loop proposes one change, benchmarks it, and either approves or rejects based on measurable improvement and correctness. Rejected loops are kept in the record — failures are as instructive as wins.

All loops

Loop	Name	Result	Delta	Status	Description
01	Redundant Query Elimination	1829→1305ms	-28.7%	Approved	Removed redundant third query; derived count in-memory
02	Parallel Query Execution	1071→852ms	-20.4%	Approved	Ran two independent queries concurrently
03	Batch Query with Shared CTEs	1177→1205ms	+2.4%	Rejected	Forced sequential execution, lost parallelism
04	CTE Pipeline Reduction	1061→1047ms	-1.3%	Rejected	Database already inlines single-reference CTEs
05	PREWHERE Bot Filter	1079→1095ms	+1.5%	Rejected	Bot ratio too low for measurable I/O savings
06	Server-Side Query Cache	925→214ms	-76.9%	Skipped	App already cached at application layer
07	CTE Re-execution Elimination	1049→700ms	-33.3%	Approved	Replaced double-referenced CTE with window function
08	CTE Re-execution (Second Pass)	961→749ms	-22.1%	Approved	Applied CTE linearization one level downstream
09	CTE Double-Reference Elimination	496→451ms	-9.1%	Approved	Eliminated final CTE double-reference
10	INNER JOIN to IN Subquery	481→462ms	-3.9%	Rejected	Improvement below 5% threshold
11	CTE Consolidation	632→605ms	-4.2%	Rejected	Improvement below 5% threshold
12	Group Boundary Simplification	712→629ms	-11.7%	Rejected	Correctness failure on tied timestamps
13	Arithmetic DESC Sort Elimination	814→643ms	-21.0%	Rejected	Correctness failure on tied timestamps
14	Map Signal Early Termination	531→509ms	-3.66%	Approved	Convergence detection for early termination
15	Combine Filtering Passes	509→509ms	~0%	Approved	Code quality; no measurable time gain
16	Element Data Pre-Computation	475→352ms	-25.9%	Approved	Pre-computed metrics in database layer

Cumulative impact

Original: 1,829ms → Final: 352ms (80.8% total reduction)