Benchmark native backend production query shapes

[chubes4]

Summary

• add production-shaped hierarchy and plugin-table inventory workloads
• attest the configured database backend against the active $wpdb implementation in every decision workload
• add SQLite and native Homeboy rigs with an immutable installed-site seed for custom-drop-in boot
• add an identical bounded concurrent HTTP read workload to both rigs
• validate benchmark rig component-path ownership

Tracks #232.

Current Evidence

The first valid native custom-drop-in run passed end to end:

• Homeboy run: ca01608d-ad76-47d5-915a-2c7062f218b8
• reproduction: homeboy bench --path <checkout> --placement local --rig mdi-native --scenario boot-timing --iterations 1 --warmup 0
• selected workload: exactly boot-timing, source in_tree
• MDI revision: 34c5d1c
• active runtime: WP_Markdown_Native_WPDB, enforced by fail-closed workload attestation

The workload had no boot phase/shared state and therefore only proves runtime selection and execution, not a meaningful performance comparison. Prior native timings collected before backend attestation are invalid because WP_SQLite_DB remained active.

The concurrent-read source contract is now present at f4b02ce:

• both rigs issue 20 host-side requests at concurrency 4 against one runtime
• every request asserts the exact expected $wpdb class and executes the same bounded wp_users query
• both rig JSON documents resolve successfully and the native query shape passes tests/smoke-native-order.php
• runtime comparison remains pending because Homeboy admission refused execution while the controller host was hot and Lab inventory was stale

Upstream Repairs

• Bench: select custom drop-in setup for pre-install db.php mounts wp-codebox#2410 selects existing custom-drop-in setup for pre-install db.php mounts
• feat(bench): add bounded external HTTP load wp-codebox#2415 adds the bounded single-runtime external-http-load benchmark primitive required by concurrent-read
• WordPress: forward benchmark scenario selection Extra-Chill/homeboy-extensions#2736 forwards exact scenario selection and preserves in-tree workload layout

Remaining Work

• run concurrent-read against both attested backends after WP Codebox #2415 is available and Homeboy runtime admission recovers
• run non-skipped production workloads against both attested backends
• add native correlated NOT EXISTS support before treating wiki-hierarchy as comparable
• collect repeated comparison evidence only after correctness passes

Verification

• native runtime activation probe returned WP_Markdown_Native_WPDB and activate_plugin(): ok
• native boot-timing Homeboy run passed with exact workload provenance
• php tests/smoke-native-order.php
• php -l tests/bench-fixtures/concurrent-read-endpoint.php
• both rig JSON files parse and resolve through homeboy rig show
• git diff --check

AI Assistance

OpenAI GPT-5.6 Sol via OpenCode traced false backend selection and benchmark orchestration failures across MDI, WP Codebox, and Homeboy Extensions; implemented the fixture, attestation, and concurrent request changes; dispatched upstream repairs; and collected the available evidence under my direction.