Validation Cache

Status: Current Last updated: 2026-05-01 17:07 EDT

The CHAT-core validation cache, used by chatter validate and the LSP server. Distinct from the result cache used by Batchalign for text and audio backend results: this cache stores parse + validate results keyed by file path + options.

crates/talkbank-transform/src/unified_cache/.

Architecture

flowchart TD
    req["Validation request\n(path + options)"]
    key["Cache key\n(path + check_alignment flag)"]
    db["SQLite WAL\n~/.cache/talkbank-chat/\ntalkbank-cache.db"]
    hit["Cache hit\n→ return stored result"]
    miss["Cache miss\n→ parse + validate + store"]

    req --> key --> db
    db -->|found + version match| hit
    db -->|not found or stale| miss
    miss --> db

Configuration

Config	Value	Why
Backend	SQLite via `sqlx`	Concurrent reads (WAL), atomic writes, zero-config
Pool size	16 connections	Matches validation worker count
`mmap`	256 MB	Fast random access for 95k+ entries
Invalidation	Version field + 30-day TTL	Schema changes auto-invalidate; stale entries pruned
Bridge	Embedded single-threaded tokio runtime	Sync workers call `rt.block_on()` for async SQLite

Schema

file_cache table:

Column	Role
`file_path`	Primary key — absolute resolved path
`check_alignment`	Whether alignment validation was requested
`parser_kind`	Parser backend (tree-sitter or re2c)
`result`	Serialized validation outcome
`cached_at`	Insertion timestamp
`version`	Schema/code version — mismatch invalidates the entry

Database location

Platform	Path
macOS	`~/Library/Caches/talkbank-chat/talkbank-cache.db`
Linux	`~/.cache/talkbank-chat/talkbank-cache.db`
Windows	`%LocalAppData%\talkbank-chat\talkbank-cache.db`

Invalidation

Schema changes — bump the version field; old entries become unreachable.
Time-based — entries older than 30 days are pruned.
Manual — pass --force to bypass cache lookups for a particular validation run.

Per project policy, do not delete the cache directory without explicit request — see the cache-policy section of talkbank-tools/CLAUDE.md.

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