presto-thrift/src/main/java/io/prestosql/plugin/thrift/ThriftModule.java/ThriftModule/createMetadataRefreshExecutor
class ThriftModule:    @Provides
    @Singleton
    @ForMetadataRefresh
    public Executor createMetadataRefreshExecutor(ThriftConnectorConfig config)
    {
        return newFixedThreadPool(config.getMetadataRefreshThreads(), daemonThreadsNamed("metadata-refresh-%s"));
    }