fix(memory): make key globally unique, 409 on any duplicate

Switches from the compound unique `(key, user_id, team_id)` to a simple
`key @unique`. The compound form silently allowed duplicates when
user_id or team_id was NULL (Postgres treats each NULL as distinct), so
callers could POST the same key repeatedly. Globally-unique key means
one row per key, period — any duplicate create → 409.

- schema.prisma (×3): `key String @unique`, drop `@@unique(...)`.
- initial add_memory_table migration: unique index on (key) only.
- Remove the now-unused follow-up NULLS NOT DISTINCT migration.
- Endpoint error message simplified ("already exists" — no "for this scope").
- Test fake's create() now enforces global key uniqueness.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

litellm-proxy-extras/litellm_proxy_extras/migrations/20260421120000_add_memory_table/migration.sql

@@ -14,8 +14,9 @@ CREATE TABLE IF NOT EXISTS "LiteLLM_MemoryTable" (
     CONSTRAINT "LiteLLM_MemoryTable_pkey" PRIMARY KEY ("memory_id")
 );
 
--- CreateIndex
-CREATE UNIQUE INDEX IF NOT EXISTS "LiteLLM_MemoryTable_key_user_id_team_id_key" ON "LiteLLM_MemoryTable"("key", "user_id", "team_id");
+-- CreateIndex (key is globally unique — one row per key, period)
+CREATE UNIQUE INDEX IF NOT EXISTS "LiteLLM_MemoryTable_key_key"
+    ON "LiteLLM_MemoryTable"("key");
 
 -- CreateIndex
 CREATE INDEX IF NOT EXISTS "LiteLLM_MemoryTable_user_id_idx" ON "LiteLLM_MemoryTable"("user_id");

litellm-proxy-extras/litellm_proxy_extras/migrations/20260423090000_memory_unique_nulls_not_distinct/migration.sql

@@ -1,34 +0,0 @@
--- Fix duplicate-key issue on LiteLLM_MemoryTable.
---
--- Problem: the unique constraint `(key, user_id, team_id)` does not block
--- duplicates when `user_id` or `team_id` is NULL, because by default
--- Postgres treats each NULL as distinct (ANSI SQL semantics). Callers with
--- no team_id could POST the same key repeatedly and get multiple rows.
---
--- Fix (Postgres 15+): recreate the unique index with NULLS NOT DISTINCT so
--- NULL values are treated as equal for uniqueness checks.
---
--- Note: Prisma has no schema syntax for NULLS NOT DISTINCT (as of writing),
--- so this lives as a raw SQL migration. Prisma introspection will still see
--- the index as uniquely covering `(key, user_id, team_id)`, matching the
--- `@@unique` in schema.prisma.
-
--- 1. Deduplicate existing rows: keep only the most-recently-updated row per
---    (key, user_id, team_id), using IS NOT DISTINCT FROM so NULL == NULL.
-DELETE FROM "LiteLLM_MemoryTable" a
-USING "LiteLLM_MemoryTable" b
-WHERE a.memory_id <> b.memory_id
-  AND a.key = b.key
-  AND a.user_id IS NOT DISTINCT FROM b.user_id
-  AND a.team_id IS NOT DISTINCT FROM b.team_id
-  AND (
-    a.updated_at < b.updated_at
-    OR (a.updated_at = b.updated_at AND a.memory_id < b.memory_id)
-  );
-
--- 2. Drop the old (NULL-distinct) unique index.
-DROP INDEX IF EXISTS "LiteLLM_MemoryTable_key_user_id_team_id_key";
-
--- 3. Recreate with NULLS NOT DISTINCT.
-CREATE UNIQUE INDEX "LiteLLM_MemoryTable_key_user_id_team_id_key"
-    ON "LiteLLM_MemoryTable"("key", "user_id", "team_id") NULLS NOT DISTINCT;

litellm-proxy-extras/litellm_proxy_extras/schema.prisma

@@ -1229,7 +1229,7 @@ model LiteLLM_ClaudeCodePluginTable {
 // `metadata` is an optional JSON envelope for structured tags without schema changes.
 model LiteLLM_MemoryTable {
   memory_id   String   @id @default(uuid())
-  key         String
+  key         String   @unique
   value       String
   metadata    Json?
   user_id     String?
@@ -1239,7 +1239,6 @@ model LiteLLM_MemoryTable {
   updated_at  DateTime @default(now()) @updatedAt
   updated_by  String?
 
-  @@unique([key, user_id, team_id])
   @@index([user_id])
   @@index([team_id])
 }

litellm/proxy/memory/memory_endpoints.py

@@ -138,12 +138,12 @@ async def create_memory(
     try:
         row = await prisma_client.db.litellm_memorytable.create(data=create_data)
     except Exception as e:
-        # Unique constraint (key, user_id, team_id) → 409.
+        # Key is globally unique. Any duplicate → 409.
         msg = str(e)
         if "Unique" in msg or "unique" in msg or "UniqueViolation" in msg:
             raise HTTPException(
                 status_code=409,
-                detail=f"Memory with key '{body.key}' already exists for this scope.",
+                detail=f"Memory with key '{body.key}' already exists.",
             )
         verbose_proxy_logger.exception("Error creating memory: %s", e)
         raise HTTPException(status_code=500, detail=str(e))

litellm/proxy/schema.prisma

@@ -1229,7 +1229,7 @@ model LiteLLM_ClaudeCodePluginTable {
 // `metadata` is an optional JSON envelope for structured tags without schema changes.
 model LiteLLM_MemoryTable {
   memory_id   String   @id @default(uuid())
-  key         String
+  key         String   @unique
   value       String
   metadata    Json?
   user_id     String?
@@ -1239,7 +1239,6 @@ model LiteLLM_MemoryTable {
   updated_at  DateTime @default(now()) @updatedAt
   updated_by  String?
 
-  @@unique([key, user_id, team_id])
   @@index([user_id])
   @@index([team_id])
 }

schema.prisma

@@ -1229,7 +1229,7 @@ model LiteLLM_ClaudeCodePluginTable {
 // `metadata` is an optional JSON envelope for structured tags without schema changes.
 model LiteLLM_MemoryTable {
   memory_id   String   @id @default(uuid())
-  key         String
+  key         String   @unique
   value       String
   metadata    Json?
   user_id     String?
@@ -1239,7 +1239,6 @@ model LiteLLM_MemoryTable {
   updated_at  DateTime @default(now()) @updatedAt
   updated_by  String?
 
-  @@unique([key, user_id, team_id])
   @@index([user_id])
   @@index([team_id])
 }

tests/test_litellm/proxy/memory/test_memory_endpoints.py

@@ -84,12 +84,9 @@ class _InMemoryMemoryTable:
         return [r for r in self.rows if self._matches(r, where)]
 
     async def create(self, data: Dict[str, Any]) -> MagicMock:
+        # Key is globally unique.
         for r in self.rows:
-            if (
-                r.key == data["key"]
-                and r.user_id == data.get("user_id")
-                and r.team_id == data.get("team_id")
-            ):
+            if r.key == data["key"]:
                 raise Exception("UniqueViolation: duplicate key")
         self._counter += 1
         row = _make_row(