1. A computer-implemented method comprising: maintaining, by a first computing member of a distributed data management system, a data region comprising a plurality of data entry keys and respective data entry values; maintaining, by the first computing member of the distributed data management system, a plurality of log entries in an event file of an operation log for the data region maintained by the first computing member of the distributed data management system, wherein the event file stores log entries representing respective requests to create or update a respective data entry of the data region, wherein each log entry in the event file has a unique event identifier; generating, by the first computing member in operational memory, a first index that stores a mapping between data entry values and respective data entry keys; generating, by the first computing member in non-operational memory, an index reference file that stores a mapping between data entry values occurring in the first index and respective unique event identifiers of log entries representing respective requests to create or update data entry keys to have one of the data entry values occurring in the first index; receiving, by a second computing member of the distributed data management system, a request to generate a second index in operational memory from the index reference file stored in non-operational memory; and in response to the request, generating, by the second computing member in operational memory, a second index that stores a mapping between data entry values stored in the index reference file and respective unique event identifiers of log entries stored in the index reference file, and wherein each log entry represented in the second index can be used by the second computing member to restore a mapping between a particular data entry value and one or more data entry keys that was previously represented in the first index.