1. A method comprising performing a machine-executed operation involving instructions, wherein the machine-executed operation is at least one of: A) sending said instructions over transmission media; B) receiving said instructions over transmission media; C) storing said instructions onto a machine-readable storage medium; and D) executing the instructions; wherein said instructions are instructions which, when executed by one or more processors, cause the one or more processors to perform the steps of: when changes are made to indexed information, storing an indication that an index has to be changed, wherein the step of storing an indication is performed in a first operation that is synchronous relative to the changes, wherein the index is not changed during said first operation; and in response to detecting that certain conditions have been satisfied, performing a second operation that updates the index and removes the indications that the index has to be changed, wherein the second operation is performed asynchronously relative to the changes made to the indexed information.