perf(native): fix full-build regression from NativeDbProxy overhead

src/domain/graph/builder/native-db-proxy.ts

@@ -27,6 +27,9 @@ export class NativeDbProxy implements BetterSqlite3Database {
 
   prepare<TRow = unknown>(sql: string): SqliteStatement<TRow> {
     const ndb = this.#ndb;
+    // Only INSERT statements need last_insert_rowid — skip the extra napi
+    // call for UPDATE/DELETE/other DML to halve per-statement overhead.
+    const isInsert = sql.trimStart().substring(0, 6).toUpperCase() === 'INSERT';
     const stmt: SqliteStatement<TRow> = {
       all(...params: unknown[]): TRow[] {
         return ndb.queryAll(sql, sanitize(params)) as TRow[];
@@ -36,10 +39,13 @@ export class NativeDbProxy implements BetterSqlite3Database {
       },
       run(...params: unknown[]): { changes: number; lastInsertRowid: number | bigint } {
         ndb.queryAll(sql, sanitize(params));
-        // Retrieve last_insert_rowid via SQLite scalar function so callers
-        // that depend on it (e.g. CFG block edge mapping) get correct values.
-        const row = ndb.queryGet('SELECT last_insert_rowid() AS rid', []) as { rid: number } | null;
-        return { changes: 0, lastInsertRowid: row?.rid ?? 0 };
+        if (isInsert) {
+          const row = ndb.queryGet('SELECT last_insert_rowid() AS rid', []) as {
+            rid: number;
+          } | null;
+          return { changes: 0, lastInsertRowid: row?.rid ?? 0 };
+        }
+        return { changes: 0, lastInsertRowid: 0 };
       },
       iterate(): IterableIterator<TRow> {
         throw new Error('iterate() is not supported via NativeDbProxy');

src/domain/graph/builder/pipeline.ts

@@ -477,15 +477,30 @@ async function runPostNativeAnalysis(
     const native = loadNative();
     if (native?.NativeDatabase) {
       try {
+        // Checkpoint JS WAL before opening native connection so both
+        // connections see the same DB state (structure writes are flushed).
+        ctx.db.pragma('wal_checkpoint(TRUNCATE)');
         ctx.nativeDb = native.NativeDatabase.openReadWrite(ctx.dbPath);
-        if (ctx.engineOpts) ctx.engineOpts.nativeDb = ctx.nativeDb;
+        if (ctx.engineOpts) {
+          ctx.engineOpts.nativeDb = ctx.nativeDb;
+          ctx.engineOpts.suspendJsDb = () => {
+            ctx.db.pragma('wal_checkpoint(TRUNCATE)');
+          };
+          ctx.engineOpts.resumeJsDb = () => {
+            try {
+              ctx.nativeDb?.exec('PRAGMA wal_checkpoint(TRUNCATE)');
+            } catch (e) {
+              debug(
+                `resumeJsDb: WAL checkpoint failed (nativeDb may already be closed): ${toErrorMessage(e)}`,
+              );
+            }
+          };
+        }
       } catch {
         ctx.nativeDb = undefined;
         if (ctx.engineOpts) ctx.engineOpts.nativeDb = undefined;
       }
     }
-  } else if (ctx.engineOpts) {
-    ctx.engineOpts.nativeDb = ctx.nativeDb;
   }
 
   try {
@@ -633,8 +648,13 @@ async function tryNativeOrchestrator(
   const needsStructure = !result.structureHandled;
 
   if (needsAnalysis || needsStructure) {
-    // In native-first mode the proxy is already wired — no WAL handoff needed.
-    if (!ctx.nativeFirstProxy && !handoffWalAfterNativeBuild(ctx)) {
+    // Always hand off to better-sqlite3 for JS post-processing.
+    // The NativeDbProxy has per-statement napi serialization overhead that
+    // makes structure/analysis phases significantly slower than direct
+    // better-sqlite3. Native bulk-insert methods (bulkInsertCfg, etc.)
+    // are wired through engineOpts.nativeDb in runPostNativeAnalysis.
+    if (ctx.nativeFirstProxy) ctx.nativeFirstProxy = false;
+    if (!handoffWalAfterNativeBuild(ctx)) {
       // DB reopen failed — return partial result
       return formatNativeTimingResult(p, 0, analysisTiming);
     }

src/features/cfg.ts

@@ -369,7 +369,7 @@ export async function buildCFGData(
   db: BetterSqlite3Database,
   fileSymbols: Map<string, FileSymbols>,
   rootDir: string,
-  _engineOpts?: {
+  engineOpts?: {
     nativeDb?: { bulkInsertCfg?(entries: Array<Record<string, unknown>>): number };
     suspendJsDb?: () => void;
     resumeJsDb?: () => void;
@@ -379,11 +379,56 @@ export async function buildCFGData(
   // skip WASM parser init, tree parsing, and JS visitor entirely — just persist.
   const allNative = allCfgNative(fileSymbols);
 
-  // NOTE: nativeDb.bulkInsertCfg is intentionally NOT used here.
-  // The CFG path requires delete-before-insert (deleteCfgForNode) which creates
-  // a dual-connection WAL conflict when deletes go through JS (better-sqlite3)
-  // and inserts go through native (rusqlite). The JS-only persistNativeFileCfg
-  // path below handles both on a single connection safely.
+  // ── Native bulk-insert fast path ──────────────────────────────────────
+  // The Rust bulkInsertCfg handles delete-before-insert atomically on a
+  // single rusqlite connection, so there is no dual-connection WAL conflict.
+  const nativeDb = engineOpts?.nativeDb;
+  if (allNative && nativeDb?.bulkInsertCfg) {
+    const entries: Array<Record<string, unknown>> = [];
+    for (const [relPath, symbols] of fileSymbols) {
+      const ext = path.extname(relPath).toLowerCase();
+      if (!CFG_EXTENSIONS.has(ext)) continue;
+
+      for (const def of symbols.definitions) {
+        if (def.kind !== 'function' && def.kind !== 'method') continue;
+        if (!def.line) continue;
+
+        const nodeId = getFunctionNodeId(db, def.name, relPath, def.line);
+        if (!nodeId) continue;
+
+        const cfg = def.cfg as { blocks?: CfgBuildBlock[]; edges?: CfgBuildEdge[] } | undefined;
+        if (!cfg?.blocks?.length) continue;
+
+        entries.push({
+          nodeId,
+          blocks: cfg.blocks.map((b) => ({
+            index: b.index,
+            blockType: b.type,
+            startLine: b.startLine ?? null,
+            endLine: b.endLine ?? null,
+            label: b.label ?? null,
+          })),
+          edges: (cfg.edges || []).map((e) => ({
+            sourceIndex: e.sourceIndex,
+            targetIndex: e.targetIndex,
+            kind: e.kind,
+          })),
+        });
+      }
+    }
+
+    if (entries.length > 0) {
+      let inserted = 0;
+      try {
+        engineOpts?.suspendJsDb?.();
+        inserted = nativeDb.bulkInsertCfg(entries);
+      } finally {
+        engineOpts?.resumeJsDb?.();
+      }
+      info(`CFG (native bulk): ${inserted} functions analyzed`);
+    }
+    return;
+  }
 
   const extToLang = buildExtToLangMap();
   let parsers: unknown = null;