BE-457: HashQL: MIR execution pipeline extensions for postgres compilation

[indietyp]

🌟 What is the purpose of this PR?

Prepares the MIR execution pipeline for consumption by the postgres compiler. The execution analysis now produces a complete IslandGraph (not just a flat island list), the placement solver and island placement accept external allocators, and the traversal system gains the TraversalPathBitMap and as_symbol() APIs that the SQL generator needs. Also adds a backend switch cost to the terminator placement so cross-backend transitions are no longer free.

🔍 What does this change?

Execution analysis (pass/execution/mod.rs):

• run() becomes run_in() with an explicit allocator parameter, returning ExecutionAnalysisResidual (assignment + island graph). The island graph is now constructed as part of the analysis rather than left to the caller.
• Adds run_all_in() which runs the execution analysis over all graph-read bodies in a DefIdSlice.

Traversal system (traversal/mod.rs, traversal/entity.rs):

• TraversalPathBitMap: per-vertex-type collection of TraversalPathBitSets with pointwise lattice operations. The postgres compiler uses this to track which paths each island accesses across all vertex types.
• TraversalPath::as_symbol(): returns a static symbol for each path variant, used as SQL column aliases so the interpreter can locate result columns by name.
• TraversalPathBitSet::vertex(): returns the vertex type for a bitset.
• EntityPath::as_symbol() and EntityPath::column_name(): per-path SQL identifiers.

Terminator placement (terminator_placement/mod.rs):

• TransMatrix gains AddAssign for element-wise saturating addition.
• Adds backend_switch_cost() which encodes a fixed overhead for cross-backend transitions (Postgres to Interpreter: 8, Interpreter to Embedding: 4, etc.). Previously cross-backend transitions had zero inherent cost, so empty blocks were arbitrarily assigned to the interpreter even when staying on postgres was free.

Placement solver (placement/solve/):

• PlacementSolver::run() becomes run_in() with allocator parameter.
• CSP solver internal allocations use the provided allocator.

Island graph (island/graph/mod.rs):

• IslandGraph::new_in() now takes an allocator for its output storage.

Pretty printer (pretty/text.rs):

• TextFormatAnnotations gains annotate_basic_block() and BasicBlockAnnotation associated type, plus a blanket impl for &mut T.

Builder (builder/rvalue.rs):

• Adds RValueBuilder::opaque_entity_uuid() convenience constructor for the common pattern of extracting an entity's UUID.

Pre-Merge Checklist 🚀

🚢 Has this modified a publishable library?

This PR:

• does not modify any publishable blocks or libraries, or modifications do not need publishing

📜 Does this require a change to the docs?

The changes in this PR:

• are internal and do not require a docs change

🕸️ Does this require a change to the Turbo Graph?

The changes in this PR:

• do not affect the execution graph

⚠️ Known issues

The backend_switch_cost() values (8, 4, etc.) are hand-tuned heuristics. They correctly prevent the solver from arbitrarily switching backends for empty blocks, but a proper cost model would derive these from measured overhead.

🛡 What tests cover this?

• Updated execution pass end-to-end tests (execution/tests.rs) including entity_uuid_equality, mixed_postgres_embedding_interpreter, projection_and_apply_splits
• Updated statement placement tests for interpret and postgres backends (eq_opaque_entity_uuid)
• Updated terminator placement and island tests
• Placement solver tests updated for allocator API

❓ How to test this?

cargo nextest run -p hashql-mir

[cursor]

PR Summary

Medium Risk
Touches core MIR execution/placement logic by changing allocator threading, island graph construction, and transition cost modeling; incorrect costs or graph wiring could change backend assignment/scheduling outcomes.

Overview
Execution analysis is refactored to return an ExecutionAnalysisResidual containing the final per-block target assignment and a fully-built IslandGraph, with run() replaced by allocator-aware run_in() plus a new run_all_in() for analyzing all GraphReadFilter bodies.

Placement/island infrastructure is updated to accept external allocators (PlacementSolver::run_in, IslandPlacement::run_in, IslandGraph::new_in) and the island graph API is expanded (members, contains, find). Terminator placement now adds a fixed per-backend switch overhead (via backend_switch_cost() and TransMatrix +=) so cross-backend edges are no longer “free”, shifting solver preferences.

Traversal utilities gain SQL-friendly identifiers (TraversalPath::as_symbol, EntityPath::as_symbol) and a new TraversalPathBitMap lattice type for tracking paths across vertex types. MIR building/pretty-printing and tests/benchmarks are updated accordingly (including new opaque aggregate support and new/updated snapshots for entity-uuid equality).

^{Reviewed by Cursor Bugbot for commit 0bd3b25. Bugbot is set up for automated code reviews on this repo. Configure here.}

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
hash	Ready	Preview, Comment	Apr 21, 2026 5:15pm
petrinaut	Ready	Preview	Apr 21, 2026 5:15pm

2 Skipped Deployments

Project	Deployment	Actions	Updated (UTC)
hashdotdesign	Ignored	Preview	Apr 21, 2026 5:15pm
hashdotdesign-tokens	Ignored	Preview	Apr 21, 2026 5:15pm

[indietyp]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• BE-515: HashQL: Remove OFFSET 0 materialization fence from generated query #8650
• BE-514: HashQL: implement iterative adjustment passes in placement solver #8635
• BE-500, BE-501: HashQL: Unify mixed parameter resolution in data dependency analysis #8607
• BE-494: HashQL: Loop-breaker selection for recursive inlining #8600
• BE-482: HashQL: Remove logical not from MIR and fix postgres boolean lowering #8595
• BE-474: HashQL: Take into account terminator target eligibility in execution backend placement #8587
• BE-455: HashQL: Introduce evaluation orchestrator #8586
• BE-306: HashQL: PostgreSQL translation #8526
• BE-457: HashQL: MIR execution pipeline extensions for postgres compilation #8525 👈 (View in Graphite)
• BE-456: HashQL: Entity type model enrichment and graph store query extensions #8524
• BE-429: HashQL: Add island dependency graph with data requirement resolution #8501
• BE-428: HashQL: Simplify traversal tracking to path recording #8498
• BE-434: HashQL: Refactor entity storage path resolution with centralized schema mapping #8496
• BE-427: Add hashql-macros crate with procedural macros for ID types and symbols #8495
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.

[augmentcode]

🤖 Augment PR Summary

Summary: Prepares the HashQL MIR execution pipeline for Postgres compilation by returning a full island dependency graph and exposing traversal/placement APIs needed by the SQL generator.
Key Changes:

• Execution analysis now takes an explicit allocator (run_in) and returns ExecutionAnalysisResidual (assignment + IslandGraph); adds run_all_in for batch analysis.
• Traversal adds TraversalPathBitMap, TraversalPath::as_symbol(), and EntityPath::as_symbol()/column_name() for stable SQL column aliases.
• Placement solver and island placement APIs accept external allocators and route CSP internal allocations through the provided bump allocator.
• Terminator placement introduces a fixed backend_switch_cost() so cross-backend transitions have non-zero overhead (avoids “free” backend flips).
• Island graph gains helper queries (members, contains, find) and is now built/resolved within execution analysis.
• Pretty printer supports per-basic-block annotations; MIR builder gains an opaque aggregate constructor and new tests cover opaque UUID equality.

Tests: Updates/extends execution, statement placement, terminator placement, and allocator-related solver snapshots (incl. entity_uuid_equality). Notes: Backend switch costs are heuristics intended to be refined by a measured cost model.

_{🤖 Was this summary useful? React with 👍 or 👎}

[augmentcode]

Review completed. No suggestions at this time.

Comment augment review to trigger a new review at any time.

[codecov]

Codecov Report

❌ Patch coverage is 64.24581% with 128 lines in your changes missing coverage. Please review.
✅ Project coverage is 62.74%. Comparing base (bc50eb0) to head (0bd3b25).

Files with missing lines	Patch %	Lines
...cal/hashql/mir/src/pass/execution/traversal/mod.rs	0.00%	44 Missing ⚠️
libs/@local/hashql/mir/src/pretty/text.rs	21.62%	28 Missing and 1 partial ⚠️
.../hashql/mir/src/pass/execution/traversal/entity.rs	0.00%	28 Missing ⚠️
libs/@local/hashql/mir/src/pass/execution/mod.rs	44.00%	14 Missing ⚠️
.../hashql/mir/src/pass/execution/island/graph/mod.rs	35.29%	11 Missing ⚠️
.../mir/src/pass/execution/placement/solve/csp/mod.rs	90.00%	0 Missing and 1 partial ⚠️
libs/@local/hashql/mir/src/pass/execution/tests.rs	99.07%	1 Missing ⚠️

Additional details and impacted files

@@                                           Coverage Diff                                           @@
##           bm/be-456-hashql-entity-type-model-enrichment-and-graph-store-query    #8525      +/-   ##
=======================================================================================================
- Coverage                                                                62.77%   62.74%   -0.03%     
=======================================================================================================
  Files                                                                     1327     1326       -1     
  Lines                                                                   135968   135760     -208     
  Branches                                                                  5530     5526       -4     
=======================================================================================================
- Hits                                                                     85350    85181     -169     
+ Misses                                                                   49706    49664      -42     
- Partials                                                                   912      915       +3     

Flag	Coverage Δ
rust.hashql-compiletest	29.69% <ø> (ø)
rust.hashql-mir	92.08% <64.24%> (-0.37%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[codspeed-hq]

Merging this PR will not alter performance

✅ 24 untouched benchmarks
⏩ 56 skipped benchmarks¹

---

_{Comparing bm/be-457-hashql-mir-execution-pipeline-extensions-for-postgres (0bd3b25) with bm/be-456-hashql-entity-type-model-enrichment-and-graph-store-query (bc50eb0)}

Footnotes

1. 56 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

^{Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.}

[vercel]

Deployment failed with the following error:

Invalid request: `attribution.gitUser` should NOT have additional property `isBot`.

Latest approval commit db87959 is not an ancestor of c67124e, indicating rewritten history after approval