feat(base): env vars for per-instance duckdb memory limit + threads

apps/server/src/core/base/query-cache/query-cache.config.ts

@@ -6,6 +6,8 @@ export type QueryCacheConfig = {
   minRows: number;
   maxCollections: number;
   warmTopN: number;
+  memoryLimit: string;
+  threads: number;
 };
 
 @Injectable()
@@ -17,6 +19,8 @@ export class QueryCacheConfigProvider {
       minRows: env.getBaseQueryCacheMinRows(),
       maxCollections: env.getBaseQueryCacheMaxCollections(),
       warmTopN: env.getBaseQueryCacheWarmTopN(),
+      memoryLimit: env.getBaseQueryCacheMemoryLimit(),
+      threads: env.getBaseQueryCacheThreads(),
     };
   }
 }

apps/server/src/integrations/environment/environment.service.ts

@@ -343,4 +343,23 @@ export class EnvironmentService {
         .toLowerCase() === 'true'
     );
   }
+
+  getBaseQueryCacheMemoryLimit(): string {
+    // Per-DuckDB-instance memory ceiling. DuckDB accepts human-readable sizes:
+    // '32MB', '128MB', '1GB'. Default keeps a single instance from
+    // monopolising the heap if a runaway query needs to spill.
+    return this.configService.get<string>(
+      'BASE_QUERY_CACHE_MEMORY_LIMIT',
+      '64MB',
+    );
+  }
+
+  getBaseQueryCacheThreads(): number {
+    // Per-DuckDB-instance thread budget. Defaults to 2 so multiple concurrent
+    // instances don't fight for every core on a shared host.
+    return parseInt(
+      this.configService.get<string>('BASE_QUERY_CACHE_THREADS', '2'),
+      10,
+    );
+  }
 }