You can set the merge policy of the MDEX Engine via a Dgraph command flag or a URL command.

An MDEX Engine's merge policy determines how frequently it merges partial update generations. The data layer that stores the index is a versioning data store. As a result:

A version is persisted as a sequence of generation files. A new version appends a new generation file to the sequence. Query latency depends, in part, on the number and size of generation files used to store the index.

Generation files are combined through a process called merging. Merging is a background task that does not affect the MDEX Engine functionality, but may affect its performance. Because of this, you can set the policy that dictates the aggressiveness of the merges; this policy is called the merge policy.

The merge policy can be controlled through a Dgraph flag or through the admin interface via a URL command. Using these controls, you can set the merge policy to one of two settings:

The balanced policy is recommended for the majority of applications. But aggressive merging may help those applications that meet the following criteria: