1. A computer-executed method comprising: maintaining a hierarchy of hash tables, each hash table of the hierarchy of hash tables storing information for child resources of a container resource in a hierarchy of resources; maintaining a session-level hash table, distinct from the hierarchy of hash tables, that stores information for resources in the hierarchy of resources; and determining, by a particular process, information for a target resource of a particular path expression by: determining whether information corresponding to the particular path expression is stored at the session-level hash table; in response to determining that the information corresponding to the particular path expression is not stored at the session-level hash table, determining whether information for resources corresponding to segments of the particular path expression are represented in the hierarchy of hash tables; and wherein the method is performed by one or more computing devices.