refactor: cache prepared statements in applyEdgeTechniquesAfterNativeInsert chunk loop

[carlos-alm]

Summary

• applyEdgeTechniquesAfterNativeInsert re-prepare()d two SQL statements from scratch on every chunk iteration instead of caching by chunk size, in a hot transactional edge-finalization path.
• Adopted the shared getOrCreatePerDbChunkStmt primitive from Consider adopting chunk-size statement-cache helper in features/structure.ts::batchUpdateRoles #1767, using persistent per-db caching (not per-call): this function has two call sites within buildEdges() that both pass the identical ctx.db and can both execute in one incremental rebuild (unlike batchUpdateRoles's mutually-exclusive full/incremental paths), and per-db keying is required for correctness anyway since prepared statements are bound to their originating connection (e.g. branch-compare.ts calls buildGraph() twice against different DB connections in one process).

Closes #1768

Test plan

• npm test — full suite green (3542 passed, 0 failed), including the Incremental rebuild leaves edges.technique NULL for native-engine call edges (full build sets 'ts-native') #1744 backfill regression test (3/3 passed)
• npm run lint / npx tsc --noEmit — clean
• SQL text confirmed byte-identical via git diff (no changes to the actual UPDATE statements' logic)

Stacked on #1890 (base branch fix/issue-1767-structure-chunked-stmt-cache) — only the build-edges.ts diff is this issue's change.

[greptile-apps]

Greptile Summary

This PR caches the two db.prepare() calls inside the chunk loop of applyEdgeTechniquesAfterNativeInsert that were previously recompiling SQL on every iteration, replacing them with the shared getOrCreatePerDbChunkStmt primitive from #1767. Two module-level WeakMap<BetterSqlite3Database, Map<number, SqliteStatement>> caches are introduced to scope statements per-db connection and per-chunk-size.

• Replaces per-iteration db.prepare(...) calls for the technique backfill and confidence floor UPDATE statements with lazily cached equivalents keyed by (db, chunkSize).
• Uses WeakMap keying on the db object to ensure independent connections (e.g. the branch-compare.ts dual-db scenario) never share prepared statements, and GC naturally releases cached statements when a connection is closed.
• The SQL text for both UPDATE statements is unchanged; only the compile-once caching layer is new.

Confidence Score: 5/5

Safe to merge — the change is a pure caching layer with no SQL or logic modifications.

Both UPDATE statements' SQL text and parameter binding are byte-identical to the original. The WeakMap keying on the db object correctly isolates cached statements per connection, handles the dual-db branch-compare scenario, and lets GC release statements when a connection closes. Chunk-size keying correctly accommodates the shorter final chunk. The two remaining db.prepare() calls inside the transaction (taggedRows, dynamicKindRows) are outside the chunk loop and intentionally left uncached.

No files require special attention.

Important Files Changed

Filename	Overview
src/domain/graph/builder/stages/build-edges.ts	Adds two module-level WeakMap caches and switches the chunk loop's pair of db.prepare() calls to getOrCreatePerDbChunkStmt; logic, SQL text, and parameter binding are all correct.

Sequence Diagram

%%{init: {'theme': 'neutral'}}%%
sequenceDiagram
    participant BE as buildEdges()
    participant AETANI as applyEdgeTechniquesAfterNativeInsert()
    participant Cache as techniqueBackfillStmtCache / confidenceFloorStmtCache (WeakMap)
    participant DB as BetterSqlite3Database

    BE->>AETANI: call (insertNativeBulkEdges path)
    AETANI->>DB: db.transaction(tx)
    loop chunk iteration
        AETANI->>Cache: getOrCreatePerDbChunkStmt(db, chunkSize, buildSql)
        alt cache miss (first call for this chunkSize)
            Cache->>DB: db.prepare(SQL)
            DB-->>Cache: SqliteStatement
        end
        Cache-->>AETANI: cached SqliteStatement
        AETANI->>DB: techniqueStmt.run(...chunk)
        AETANI->>DB: confidenceStmt.run(floor, floor, ...chunk)
    end

    BE->>AETANI: call (reconnectReverseDepEdges path, same db)
    AETANI->>DB: db.transaction(tx)
    loop chunk iteration
        AETANI->>Cache: getOrCreatePerDbChunkStmt(db, chunkSize, buildSql)
        note over Cache: cache HIT — statement reused across calls
        Cache-->>AETANI: cached SqliteStatement
        AETANI->>DB: techniqueStmt.run(...chunk)
        AETANI->>DB: confidenceStmt.run(floor, floor, ...chunk)
    end

Loading

%%{init: {'theme': 'base', 'themeVariables': {"darkMode": true, "background": "#0d1117", "primaryColor": "#21262d", "primaryTextColor": "#e6edf3", "primaryBorderColor": "#8b949e", "lineColor": "#8b949e", "textColor": "#e6edf3", "edgeLabelBackground": "#161b22", "actorBkg": "#21262d", "actorBorder": "#8b949e", "actorTextColor": "#e6edf3", "actorLineColor": "#8b949e", "signalColor": "#8b949e", "signalTextColor": "#e6edf3", "noteBkgColor": "#373320", "noteBorderColor": "#d4a72c", "noteTextColor": "#f0e6c0", "labelBoxBkgColor": "#21262d", "labelBoxBorderColor": "#8b949e", "labelTextColor": "#e6edf3", "loopTextColor": "#e6edf3", "activationBkgColor": "#30363d", "activationBorderColor": "#8b949e"}}}%%
sequenceDiagram
    participant BE as buildEdges()
    participant AETANI as applyEdgeTechniquesAfterNativeInsert()
    participant Cache as techniqueBackfillStmtCache / confidenceFloorStmtCache (WeakMap)
    participant DB as BetterSqlite3Database

    BE->>AETANI: call (insertNativeBulkEdges path)
    AETANI->>DB: db.transaction(tx)
    loop chunk iteration
        AETANI->>Cache: getOrCreatePerDbChunkStmt(db, chunkSize, buildSql)
        alt cache miss (first call for this chunkSize)
            Cache->>DB: db.prepare(SQL)
            DB-->>Cache: SqliteStatement
        end
        Cache-->>AETANI: cached SqliteStatement
        AETANI->>DB: techniqueStmt.run(...chunk)
        AETANI->>DB: confidenceStmt.run(floor, floor, ...chunk)
    end

    BE->>AETANI: call (reconnectReverseDepEdges path, same db)
    AETANI->>DB: db.transaction(tx)
    loop chunk iteration
        AETANI->>Cache: getOrCreatePerDbChunkStmt(db, chunkSize, buildSql)
        note over Cache: cache HIT — statement reused across calls
        Cache-->>AETANI: cached SqliteStatement
        AETANI->>DB: techniqueStmt.run(...chunk)
        AETANI->>DB: confidenceStmt.run(floor, floor, ...chunk)
    end

Loading

_{Reviews (1): Last reviewed commit: "refactor: cache prepared statements in a..." | Re-trigger Greptile}

[github-actions]

Codegraph Impact Analysis

1 functions changed → 4 callers affected across 2 files

• applyEdgeTechniquesAfterNativeInsert in src/domain/graph/builder/stages/build-edges.ts:1939 (4 transitive callers)