Problem

loadSnapshotFast Pass C calls rebuildSymbolIndexFor for every restored file. Measured on openclaw (13,654 files, ReleaseFast, warm cache) with the new CODEDB_LOAD_PROFILE sub-phase attribution:

• symidx = 18–20ms of a ~60ms load (the single largest insert cost)
• Pass C heap growth +62.5MB, one-shot codedb search = 244MB max RSS / 132.7MB phys footprint

Plain content search never reads symbol_index — every one-shot CLI search pays the inserts and heap for nothing. The codebase already has the lazy pattern for exactly this (word index: word_index_complete + rebuild-on-first-use, #539).

Failing Test

test "issue-564: snapshot fast-load defers the symbol index until first symbol use" (src/test_snapshot.zig): after loadSnapshot, symbol_index.count() must be 0, and the first findAllSymbols must build it on demand and answer correctly. Fails on release/0.2.5825 (eager build → count > 0).

Fix

Defer: markSymbolIndexIncomplete() before Pass C; rebuildSymbolIndexFor no-ops while incomplete; ensureSymbolIndex() (mirrors the lazy word-index rebuild) at every reader entry — findSymbol/findAllSymbols/searchSymbols/renderSymbols/resolveCallees/findCallPath/buildCallCentrality — and an incomplete-guard in ensureCallGraph so an empty graph is never built and cached.

Measured after (same machine/protocol)

• load ~60ms → ~40ms; symidx 18ms → 0.2ms
• Pass C heap +62.5MB → +20.5MB
• one-shot search: 244MB → 200MB max RSS; footprint 132.7MB → 89.2MB (−33%)
• codedb symbol GatewayClient correct on first (lazy) use; 537b call-edge test green