I have a question about the query against to the federated engine tables.
As the following example:
"select Id,name from e01_system.category"
Note: the "e01_system.category" is a federated table.
I select only tow fields from the federated table "category" with the above
sql statement. But it seemed as if gets all the fields of the table (the table
has more then ten fields actually), so the performance of the sql stetement is
very slow when the table's size is very big.I conclude this through monitoring
the throughput of the network with a network tool named "sniffer". I think the
federated table works not as what i expected.
