Have you selected "Extend Insert" check box to carry out a bulk insert of a defined set of lines? TalendHelpCenter:tRedshiftOutput.
In addition, tMap is cache component consuming two much memory. For a large set of data, try to store the data on disk instead of memory on tMap. Also, allocate more memory to execute the job.
Please have a look at KB article TalendHelpCenterutOfMemory.