* fix(checkpoints): reject malformed Redis history write records
Validate pending-write tuples before optional Redis history entries reach
delta materialization. Treat the whole malformed entry as a miss so the
authoritative saver rebuilds it without dropping or inventing state.
Cover actual checkpoint reads, whole-entry replacement, valid tuple/list
records, neighbor preservation and warm-cache rereads.
* fix(checkpoints): bind cached history writes to their channel
* fix(checkpoints): keep cache warning failures best-effort
Guard warning handlers across decode, ingestion, serialization, Redis outages and purge. Preserve authoritative rebuilds and valid neighboring writes, with native graph regression coverage.
* docs(gateway): keep guidance below the hard size budget
---------
Co-authored-by: Willem Jiang <willem.jiang@gmail.com>
* fix(checkpoints): isolate cached history payloads from state readers
Copy nested snapshot seeds and pending-write payloads at both cache boundaries.
Keep user copy callbacks outside the registry lock so readers cannot poison
later checkpoint materialization or deadlock by re-entering the cache.
Cover sync/async state accessor reads, nested message payloads, disabled-cache
controls and callback lock ownership.
* docs(checkpoints): document synchronous history copy costs
---------
Co-authored-by: Willem Jiang <willem.jiang@gmail.com>
* feat(checkpoint-cache): delta-mode checkpoint history cache with recursive compose
Read-only, invalidation-free cache for LangGraph delta-channel history
({writes, seed}) at the get_delta_channel_history choke point:
- database.checkpoint_cache config (memory|redis; max_entries 0=disabled;
redis bounded by TTL, Gateway/async only)
- memory LRU backend (copy-on-read, zero-serde hit path) and redis backend
(lazy import, degrades to all-miss on outage)
- CachedHistorySaver: recursive composition from the nearest warm ancestor
(depth budget 8), caching each level; depth-0 cold chains delegate one
inner fast-path walk. Entries keyed by immutable
(db, thread, ns, checkpoint_id, channel) — no invalidation, coherent
across workers
- provider wiring: wraps in delta mode only (async + sync), full mode
untouched; sync path is memory-only
- bench opt-in: DEERFLOW_CHECKPOINT_BENCH_HISTORY_CACHE=1
sqlite bench (500 updates, payload 2KB): write phase 2.28x at f=250,
1.32x at f=10; one delegated walk per thread cold start.
* chore(config): bump config_version to 32 for database.checkpoint_cache
The checkpoint history cache feature added the database.checkpoint_cache
section to config.example.yaml; bump the schema version so existing
deployments get the outdated-config warning and can run make config-upgrade.
* chore(helm): bump config_version to 32 in chart values and README
* fix(checkpoint-cache): purge thread history entries on delete paths
Addresses review on #4638: delete_thread/prune removed source-of-truth
checkpoints but left the thread's materialized history payloads in the
cache (memory: until LRU eviction; redis: until TTL, default 1 day) — a
data-lifecycle gap for tenant offboarding / GDPR-style erasure.
- Cache contract gains thread-scoped adelete_thread/delete_thread
(lifecycle purge, not invalidation; entries remain immutable)
- Memory backend: stem scan over the LRU map; redis: SCAN MATCH + UNLINK,
outage degrades to TTL-bounded retention without raising
- CachedHistorySaver purges on delete_thread/adelete_thread and
prune/aprune (prune rewrites chains, so pre-prune histories must go);
delete_for_runs stays delegation-only (run->thread mapping unavailable,
no in-tree callers), documented in code
- ttl_seconds description documents the residual-retention window
- Tests: thread-scoped purge on both backends, saver-level delete/prune
purge, prefix-safety (t1 vs t10), redis outage degradation, and the
pinned no-purge behavior of delete_for_runs
* fix(checkpoint-cache): stable db identity, prefix-aware sync singleton, explicit zero TTL
Addresses Copilot review on #4638:
- checkpoint_cache_db_hash now hashes the credential-free postgres
identity (host:port/database + schema): credential rotation no longer
changes the cache namespace (cold cache + orphaned keys until TTL).
Unparseable URLs fall back to the raw string.
- The sync-path memory cache singleton is also keyed by its key_prefix:
a namespace change (db identity change or operator override) recreates
the cache instead of leaving stale-prefix entries unreachable and
unpurgeable.
- ttl_seconds=0 is now an explicit, documented opt-out of redis expiry
(SET without EX; redis maxmemory policy only) instead of a silent
'ttl_seconds or None' coercion.
Tests: credential-rotation hash stability, unparseable-URL fallback,
prefix-change singleton recreation, same-prefix singleton reuse, and
zero-TTL wire behavior (ex=None).
---------
Co-authored-by: Willem Jiang <willem.jiang@gmail.com>
