Localized lookups for efficient database service request processing

A method, comprising:

• receiving, at a routing application, a request to access a portion of a database stored in a network-based service from a client application hosted by a same container engine as the routing application, the network-based service comprising a plurality of storage nodes that store different respective portions of a plurality of databases including the database;
• accessing, by the routing application, a storage node mapping for the network-based service to identify one of the plurality of storage nodes that stores the portion of the database;
• sending, by the routing application, the request to the identified storage node with an identification token obtained by the routing application to provide verifiable authorization to access the portion of the database at the identified storage node;
• and
• returning, by the routing application, a result for the request to the client application based, at least in part, on a response received from the identified storage node at the routing application.

One or more non-transitory, computer-readable storage media, storing program instructions that when executed on or across one or more computing devices cause the one or more computing devices to implement:

• receiving, at a routing application, a request to access a portion of a database stored in a network-based service from a client application hosted by a same container engine as the routing application, the network-based service comprising a plurality of storage nodes that store different respective portions of a plurality of databases including the database;
• identifying, by the routing application, one of the plurality of storage nodes that stores the portion of the database according to a storage node mapping for the network-based service obtained by the routing application;
• including, by the routing application, an identification token obtained by the routing application to provide verifiable authorization to access the portion of the database at the identified storage node when sending the request to the identified storage node;
• and
• returning, by the routing application, a result for the request to the client application based, at least in part, on a response received from the identified storage node at the routing application.