wiki-vault/Sources/Homelab/2026-05-15-postgres-consolidation-phase2a-result.md

---
created: '2026-05-15'
path: Sources/Homelab
project: postgres-consolidation-reflection-layer
status: active
tags:
- ob1
- mcp
- pgvector
- embeddings
- session-note
type: session-notes
updated: '2026-05-15'
worker: 2
phase: 2a
---

# Postgres Consolidation — Worker 2, Phase 2a result

Light Phase 2a complete. Disruption-free: no consumer connections
broken, no live writers paused, no schema rename. `openbrain` is still
the live DB name; `petalbrain` rename is Worker 3's cutover.

## What landed

Inside `openbrain` (the existing DB):

### New roles (no grants on `ob1` yet — that schema doesn't exist)

| Role          | Schema-level grants                                                        | search_path                    |
|---------------|----------------------------------------------------------------------------|--------------------------------|
| `vault_mcp`   | OWNER of `wiki`                                                            | `wiki, public`                 |
| `trellis_mcp` | OWNER of `trellis`                                                         | `trellis, public`              |
| `ob1_mcp`     | USAGE + SELECT on `wiki` and `trellis`                                     | `ob1, public` (ob1 not yet created) |
| `lovebug`     | USAGE + SELECT + INSERT/UPDATE/DELETE on `wiki` and `trellis`              | `wiki, ob1, trellis, public`   |

All four: LOGIN, NOSUPERUSER, NOCREATEDB, NOCREATEROLE, NOREPLICATION,
NOBYPASSRLS, INHERIT.

Default privileges configured so future tables owned by `vault_mcp`
(in `wiki`) and `trellis_mcp` (in `trellis`) inherit the same grant
model automatically.

Credentials at `/opt/backups/postgres-consolidation/credentials.env`
(mode 0600, herbyadmin-only). 64-char hex passwords. For KeePassXC
transcription.

### Schemas in `openbrain`

- `wiki` — restored from Phase 1 `herbylab-pg_dump`, then
  `ALTER SCHEMA herbylab RENAME TO wiki`. Contains:
  - tables `alembic_version` (1 row), `artifacts` (0 rows),
    `projects` (0 rows)
  - sequences `artifacts_id_seq`, `projects_id_seq` (linked to
    IDENTITY columns)
  - enums `artifact_type`, `project_status`, `project_domain`
  - functions `artifacts_set_updated_at`, `notify_project_change`
  - triggers `artifacts_updated_at_bump`, `projects_notify`
  - FK constraint `projects.artifact_id` → `artifacts.id`
  - all OID references updated transparently across the rename

- `trellis` — restored from Phase 1 `trellis-pg_dump` (same name in
  source and target, no rename). Contains:
  - tables `alembic_version` (1), `events` (50), `tags` (42),
    `thread_tags` (55), `threads` (13)
  - sequences `events_id_seq`, `tags_id_seq`, `threads_id_seq`
    (OWNED BY linked)
  - FK chain across `events ⇒ threads`, `thread_tags ⇒ threads`,
    `thread_tags ⇒ tags`, `threads.parent_id ⇒ threads`

- `public` — **untouched**. `public.thoughts` still owned by
  `postgres`, still receiving writes from `ob1-watcher` (75 rows at
  end of Phase 2a, vs 74 at Phase 1 dump start, vs 70 at Phase 0
  recon — `ob1-watcher` is healthy). Worker 3 moves this to `ob1`.

- `public.embeddings` — **new, empty**. Shared cross-schema embedding
  store per locked spec:

  ```
  public.embeddings (
    id              BIGSERIAL PRIMARY KEY,
    source_schema   TEXT NOT NULL,
    source_table    TEXT NOT NULL,
    source_id       BIGINT NOT NULL,
    embedding       VECTOR(768) NOT NULL,
    embedding_model TEXT NOT NULL,
    embedded_at     TIMESTAMPTZ NOT NULL DEFAULT now(),
    UNIQUE (source_schema, source_table, source_id, embedding_model)
  )
  ```

  Indexes:
  - `embeddings_pkey` (id)
  - `embeddings_source_uniq` UNIQUE (source_schema, source_table,
    source_id, embedding_model)
  - `idx_embeddings_hnsw` HNSW (embedding vector_cosine_ops) WITH
    (m=16, ef_construction=64) — matches the existing
    `idx_thoughts_embedding_hnsw` convention exactly
  - `idx_embeddings_source` (source_schema, source_table, source_id)
    — for orphan cleanup + source-aware queries
  - `idx_embeddings_model` (embedding_model) — for the multi-model
    coexistence case the plan calls out

  Owned by `postgres` (neutral shared infrastructure). All four
  service users have SELECT+INSERT+UPDATE+DELETE on the table and
  SELECT+USAGE on the `embeddings_id_seq` sequence. No FK — orphan
  cleanup is a separate periodic job (out of scope here per plan).

## What Phase 2a did NOT do

- Did not rename `openbrain` → `petalbrain`. That's a destructive
  cutover (live consumers must disconnect for `ALTER DATABASE
  RENAME`). Deferred to Worker 3.
- Did not create the `ob1` schema. Worker 3 owns the
  `ALTER TABLE public.thoughts SET SCHEMA ob1` step + accompanying
  shape rewrite.
- Did not touch `public.thoughts` in any way. Still in `public`,
  still writable, still being written to.
- Did not pause `ob1-watcher` or `ob1-enricher`. Both still live.
- Did not modify any MCP container connection strings or env files.
  All MCPs still connect to `openbrain` as before.
- Did not touch the source `herbylab` or `trellis` databases. Both
  still exist on the instance with their original content; cleanup
  is Phase 8 of the plan.

## Verification done

### Row counts in openbrain match dump-source counts exactly

| Schema/Table              | Live count | Dump-source count |
|---------------------------|-----------:|------------------:|
| `wiki.projects`           | 0          | 0 (herbylab)      |
| `wiki.artifacts`          | 0          | 0 (herbylab)      |
| `wiki.alembic_version`    | 1          | 1 (herbylab)      |
| `trellis.threads`         | 13         | 13                |
| `trellis.events`          | 50         | 50                |
| `trellis.tags`            | 42         | 42                |
| `trellis.thread_tags`     | 55         | 55                |
| `trellis.alembic_version` | 1          | 1                 |
| `public.thoughts`         | 75         | (live; was 74 at dump time) |
| `public.embeddings`       | 0          | (new)             |

Source `herbylab` DB and source `trellis` DB confirmed unchanged.

### Permission boundary smoke tests (positive isolation per plan Phase 3)

All ran via direct postgres connection on
`postgresql://<role>:<pw>@localhost:5432/openbrain`:

| Test                                             | Expected | Result |
|--------------------------------------------------|----------|--------|
| `vault_mcp` SELECT `wiki.artifacts`              | succeed  | OK     |
| `vault_mcp` INSERT `trellis.threads`             | DENY     | `ERROR: permission denied for schema trellis` |
| `trellis_mcp` SELECT `wiki.artifacts`            | DENY     | `ERROR: permission denied for schema wiki` |
| `ob1_mcp` SELECT `wiki.artifacts` + `trellis.threads` | succeed | OK (counts 0 + 13) |
| `ob1_mcp` INSERT `wiki.artifacts`                | DENY     | `ERROR: permission denied for table artifacts` |
| `vault_mcp` INSERT `public.embeddings`           | succeed  | OK (id 1)  |
| `ob1_mcp` INSERT `public.embeddings`             | succeed  | OK (id 2)  |
| `trellis_mcp` INSERT `public.embeddings`         | succeed  | OK (id 3)  |
| `lovebug` INSERT `public.embeddings`             | succeed  | OK (id 4)  |

Smoke-test rows (4) deleted after verification;
`public.embeddings` back to 0 rows.

## Surprises / notes

- **Sequence ownership followed table.** First pass on `ALTER OWNER`
  failed with `cannot change owner of sequence "artifacts_id_seq" —
  Sequence "artifacts_id_seq" is linked to table "artifacts"`. The
  herbylab dump uses `GENERATED ALWAYS AS IDENTITY`, whose sequence
  is owned by the table and cannot be reassigned independently.
  Fixed by excluding `relkind='S'` from the table loop; sequence
  ownership now follows the table automatically. Trellis sequences
  use SERIAL/OWNED BY which has the same behavior. Caught + handled
  in one retry; final state correct.
- **`ob1_mcp.search_path = ob1, public`** is set now even though the
  `ob1` schema doesn't exist yet. Once Worker 3 creates the schema
  in the same DB (whatever its final name), unqualified table refs
  from `ob1-mcp`'s connection will resolve there automatically.
- **No `vault-mcp` env update** was needed for Phase 2a. The current
  `HERBYLAB_DATABASE_URL` in `vault-mcp` points at hostname
  `vault-postgres` (still anomalous — part of Travis's rename
  rollout) and DB `herbylab`. Neither is wired into the consolidated
  state yet. Phase 3 of the original plan handles MCP connection
  cutover.

## Worker 3 readiness assessment

Worker 3's cutover window is the next destructive step. From the
priming, Worker 3 must:

1. Pause `ob1-watcher` + `ob1-enricher` + `ob1-mcp`.
2. Take Phase 2-start fresh `pg_dump` of `openbrain`, `herbylab`,
   `trellis` to `/opt/backups/postgres-consolidation/` with suffix
   `-phase2-start-<UTC-timestamp>`. Verify via test restore.
3. `ALTER DATABASE openbrain RENAME TO petalbrain` (now safe — no
   live connections).
4. Connect to `petalbrain` and `ALTER TABLE public.thoughts SET
   SCHEMA ob1`, plus all dependent objects (indexes are intra-table
   so they follow; the `match_thoughts` function references
   `thoughts` directly without schema qualification so search_path
   must include `ob1` when ob1_mcp calls it — already set; the
   `thoughts_updated_at` trigger follows the table; `update_updated_at()`
   function lives in `public` and should be moved or be referenced
   cross-schema).
5. Create `ob1` schema if `SET SCHEMA` didn't auto-create it
   (`SET SCHEMA` does create the schema if it didn't exist — but
   actually it requires the schema to pre-exist; Worker 3 should
   `CREATE SCHEMA ob1 AUTHORIZATION ob1_mcp` first).
6. ob1-specific grants: `ob1_mcp` owns `ob1.*`; `lovebug` gets full
   RW; `vault_mcp` and `trellis_mcp` get nothing.
7. Backfill embeddings: for each of the 75-ish rows in
   `ob1.thoughts`, insert into `public.embeddings` with
   `source_schema='ob1'`, `source_table='thoughts'`, `source_id=<row
   id>`, `embedding=<existing embedding column value>`,
   `embedding_model='nomic-embed-text'`.
8. Decide: keep the `ob1.thoughts.embedding` column post-backfill
   (redundant with `public.embeddings`) or drop it. Plan says all
   embeddings live in `public.embeddings`; suggests dropping. But
   that changes the row shape for `ob1-mcp`'s code. Worker 3 call.
9. Rewrite `ob1-mcp`'s `add_thought` and `search_thoughts` for the
   new shape (target table `ob1.thoughts`, embedding pushed to
   `public.embeddings` separately, search joins).
10. Update connection strings on `ob1-mcp`, `ob1-watcher`,
    `ob1-enricher` from DB `openbrain` to DB `petalbrain`. Watcher
    talks to ob1-mcp HTTP only, so its env may not need DB host
    change — verify.
11. Update `trellis-mcp` and `herbydev-mcp` / `vault-mcp` connection
    strings from their current DBs (`trellis`, `herbylab`) to the
    consolidated `petalbrain` with their service-user credentials
    from `credentials.env`.
12. Resume `ob1-watcher` + `ob1-enricher`.
13. Verify: row counts, semantic search query roundtrip, NOTIFY
    trigger on `wiki.projects` still emits.

Phase 2a outputs Worker 3 will need:
- Service user passwords in
  `/opt/backups/postgres-consolidation/credentials.env`.
- Phase 1 backup set in `/opt/backups/postgres-consolidation/` plus
  the rollback runbook there.
- This session note.

## Holding pattern

`ob1-watcher` and `ob1-enricher` continue writing to
`public.thoughts`. Each minute that passes, the gap between the Phase
1 dump's `thoughts` snapshot (74) and the cutover-time count grows.
Phase 2-start fresh dump shrinks that gap to seconds when Worker 3
runs. Until then: no degradation, no risk; just normal capture.

Worker 2 standing by. No further actions until Worker 3 spawns or
Travis redirects.