Fix ClassLoaderSafeConnectorMetadata so that it delegates canCreateSampledTables()
Add support for sampled tables to Hive connector
Add documentation for migrating from Hive
Add missing Cassandra decimal data type mappings
fix NPE in CassandraColumnHandle toString()
Parallelize test queries in presto-main

Make all unit tests in presto-main run in parallel by default, and
annotate non-threadsafe tests with singleThreaded=true
Fix bugs of upper case Cassandra schema, table, column names
Add backpressure to InMemoryExchange
Run all tests in parallel by default

Annotate all tests that use @BeforeMethod with singleThreaded=true