Hi, here is my understanding.
GetDataTableEntries : Just retrieve rows based on maxItems which you set on input. It should be the fastest because no query or expression are defined.
SearchDataTableEntries : You can set a searchExpression and this parameter will work on partial match search against Key columns. This should be the second fastest.
QueryDataTableEntries : This service can set a query and a maxItems in input parameters. Query will work after retrieving the rows so it should be slow than the others when query is defined.
However, I cannot decide which is more efficient because it depends on your use case.
I hope this helps you.
