I found this which may be helpful:
[If the hive connection is taking a very long time]Download and install the Cloudera ODBC driver for Apache Hive version 2.5.5, 32-bit from the Drivers & Activation page.The Cloudera ODBC driver for Apache Hive version 2.5.0, 32-bit was sending a SELECT * query to the hive, making the query run longer.The initial ‘SELECT*’ statement uses SQLPrepare which just compiles the SQL and does not actually execute it. This should be the fastest method of retrieving metadata. Internally, connecting to a 300 million row table in hive via Tableau Desktop took just 0.1 seconds for the ‘SELECT *’. Manually running a ‘select count(*)’ on that table took 147 seconds by contrast.
Alternately, using the following customizations should force Tableau to send a LIMIT query:
CAP_ODBC_METADATA_SUPPRESS_PREPARED_QUERY = true
CAP_QUERY_TOP_0_METADATA = true
I am looking at customization settings for a different data source (Kognitio via generic ODBC connector) and came across your post. I got the list of CAP_ customizations from:
but the CAP_QUERY_TOP_0_METADATA isn't listed there. I will definitely try it. Do you know if there is a full list of customizations available anywhere?
I had similar issues connecting via a TDC to a different data source (Kognitio via generic ODBC) and the CAP_SUPPRESS_DISCOVERY_QUERIES didn't work for me on V8.3. However a recent upgrade to V9.0 solved the issue for me so it might work for you too.