feat(knowledgebase): replace litellm-pgvector connector with memory-retrieval

Per docs/research/langchain-pgvector-vs-litellm-pgvector.md (issue #25):
the vendored litellm-pgvector connector (793 lines, Prisma migrations, a
fragile git-context build) is replaced by a ~90-line FastAPI service
(services/memory-retrieval/) wrapping langchain_postgres.PGVector directly
against pgvector-db. Same gateway boundary — it still calls litellm for
embeddings, nothing talks to Postgres or the model directly except this
service.

- New services/memory-retrieval/ (main.py, Dockerfile, requirements.txt):
  POST /ingest, POST /query, GET /health.
- docker-compose.yml: litellm-pgvector service replaced by memory-retrieval;
  pgvector-db and embedding-server untouched.
- litellm-config.yaml: vector_store_registry block removed (no
  langchain_postgres provider exists to register against; callers query
  memory-retrieval directly instead of an in-band file_search tool call —
  that mechanism was never confirmed working per issue #24 anyway).
- scripts/ingest-memory.sh rewritten for the new /ingest endpoint (same
  per-line chunking, no dedup).
- .env vars renamed: LITELLM_PGVECTOR_API_KEY/LITELLM_PGVECTOR_EMBEDDING_KEY
  -> MEMORY_RETRIEVAL_API_KEY/MEMORY_RETRIEVAL_EMBEDDING_KEY.
- vendor/litellm-pgvector/ removed entirely.
- docs/memory-knowledgebase.md updated for the new setup/query flow.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
This commit is contained in:
2026-09-02 22:09:25 +02:00
co-authored by Claude-Bot
parent e2a79eab4a
commit abeadc49c8
21 changed files with 154 additions and 1349 deletions
+13 -14
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@@ -2,7 +2,7 @@
Three gateway-level capabilities added on top of the [AI gateway/proxy](https://git.arthurerlich.de/haylan/LLM-Server/issues/9), so every client behind LiteLLM gets them — not just Open WebUI. See [issue #21](https://git.arthurerlich.de/haylan/LLM-Server/issues/21) for the rationale.
**Not yet verified on real hardware** — see [issue #24](https://git.arthurerlich.de/haylan/LLM-Server/issues/24). In particular: `litellm-pgvector`'s Prisma migrations on first boot, and the exact `vector_store_registry` field names for the `pg_vector` provider.
**Not yet verified on real hardware** — see [issue #24](https://git.arthurerlich.de/haylan/LLM-Server/issues/24).
## Web search (SearXNG)
@@ -21,23 +21,23 @@ Requires `SEARXNG_LAN_IP` set in `.env` (SearXNG's stable LAN IP — use a stati
## Knowledgebase (vector store / RAG)
LiteLLM's native knowledgebase feature has **no Qdrant backend** — the `qdrant` service in this stack only serves Open WebUI's own separate RAG/Memory feature and is unrelated to this. The only self-hosted path is [litellm-pgvector](https://github.com/BerriAI/litellm-pgvector), a companion service backed by its own Postgres+pgvector database (`pgvector-db`), which this stack now runs alongside `litellm`. Full research: `docs/research/litellm-knowledgebase.md`.
LiteLLM's native knowledgebase feature has **no Qdrant backend** — the `qdrant` service in this stack only serves Open WebUI's own separate RAG/Memory feature and is unrelated to this — and no `langchain_postgres` backend either. Instead, a small in-repo service wraps LangChain's `PGVector` directly against its own Postgres+pgvector database (`pgvector-db`). This replaced an earlier attempt to vendor the third-party `litellm-pgvector` connector — see `docs/research/langchain-pgvector-vs-litellm-pgvector.md` for why. One consequence: the OpenAI-style `file_search` tool call on a `/chat/completions` request doesn't work here (no `vector_store_registry` entry) — query `memory-retrieval` directly instead (see below).
New pieces:
- **`embedding-server`** — a second llama.cpp instance (small footprint, `nomic-embed-text-v1.5`) serving `/v1/embeddings`. The chat model isn't embedding-trained and llama.cpp serves one model per process, so this can't just be a flag on `llama-server`.
- **`pgvector-db`** — Postgres with the pgvector extension, separate from `litellm-db`.
- **`litellm-pgvector`** — the connector service; no published image exists, so it's built from a vendored copy of the upstream repo at `vendor/litellm-pgvector/` (see that dir's `VENDORED.md`) — a remote git build context failed on the server's Docker/BuildKit setup.
- `litellm-config.yaml`'s `local-embedding` model entry and `vector_store_registry` block, tying it together.
- **`memory-retrieval`** (`services/memory-retrieval/`) — a ~90-line FastAPI app wrapping `langchain_postgres.PGVector`, exposing `POST /ingest` and `POST /query`. Calls back into `litellm` for embeddings, same gateway boundary as everything else here.
- `litellm-config.yaml`'s `local-embedding` model entry, which `memory-retrieval` calls through.
### First-time setup
```bash
docker compose --profile tools run --rm downloader-embedding # fetch the embedding model
docker compose up -d embedding-server pgvector-db litellm-pgvector
docker compose up -d embedding-server pgvector-db memory-retrieval
```
Create a `litellm-pgvector` virtual key in LiteLLM's Admin UI (per `docs/proxy-key-onboarding.md`) and set it as `LITELLM_PGVECTOR_EMBEDDING_KEY` in `.env` — the connector calls back into `litellm` for embeddings, same as any other workload.
Create a `memory-retrieval` virtual key in LiteLLM's Admin UI (per `docs/proxy-key-onboarding.md`) and set it as `MEMORY_RETRIEVAL_EMBEDDING_KEY` in `.env`it calls back into `litellm` for embeddings, same as any other workload.
### Loading memory into it
@@ -51,14 +51,13 @@ One chunk per fact/paragraph line, tagged with `source`/`section` metadata. Re-r
### Querying it
Via the OpenAI Assistants-style `file_search` tool on a chat completion:
Directly against `memory-retrieval` — no in-band `file_search` tool call (see above):
```json
{
"model": "qwen3.8-27b-local",
"messages": [...],
"tools": [{"type": "file_search", "vector_store_ids": ["memory-and-notes"]}]
}
```bash
curl -X POST http://memory-retrieval:8000/query \
-H "Authorization: Bearer <MEMORY_RETRIEVAL_API_KEY>" \
-H "Content-Type: application/json" \
-d '{"query": "...", "k": 5}'
```
or directly: `POST /v1/vector_stores/memory-and-notes/search` with `{"query": "..."}`.
A caller wanting RAG-augmented chat does the "search then send" pattern: query `/query`, splice the results into the prompt, then call `litellm` as normal.