Performance impact of schema and configuration changes

Changes to the schema and configuration can be made on an empty index (before data is loaded), or after the records have already been loaded into the Dgraph. Even though it is possible to change the schema for your records after the records have been loaded, such a change is associated with performance impact.

You can use the updateProperties or updateDimensions operations of the Configuration Web Service to update the PDRs and DDRs (the records schema) after the records have already been added to the Dgraph process index. However, changes to the schema on an existing index are not recommended for performance reasons, since such changes cause the Dgraph to reindex the data set, which is associated with an increase in CPU and memory usage.

Note also that not all changes to the PDRs and DDRs can be done on an existing data domain containing records.

In addition, changes to the configuration, such as to the settings of the GCR, while they can be done on a running data domain that contains records, are also associated with performance impact in cases when the data domain contains a large number of records.