Limit the number of nodes that process a query, typically during debugging. Only accepts the values 0 (meaning all nodes) or 1 (meaning all work is done on the coordinator node). If you are diagnosing a problem that you suspect is due to a timing issue due to distributed query processing, you can set NUM_NODES=1 to verify if the problem still occurs when all the work is done on a single node.
You might set the NUM_NODES option to 1 briefly,
during INSERT or
CREATE TABLE AS SELECT statements.
Normally, those statements produce one or more data files
per data node.
If the write operation involves small amounts of data, a Parquet
table, and/or a partitioned table, the default behavior could
produce many small files when intuitively you might expect
only a single output file.
SET NUM_NODES=1 turns off the
|<< MEM_LIMIT||NUM_SCANNER_THREADS >>|