Reduces the number of Spark partitions by logically merging partitions together.
This will not perform any shuffle operation.
mappings: facts_bidding: kind: coalesce input: facts_all partitions: 32
broadcast(optional) (type: boolean) (default: false): Hint for broadcasting the result of this mapping for map-side joins.
cache(optional) (type: string) (default: NONE): Cache mode for the results of this mapping. Supported values are
NONE- Disables caching of teh results of this mapping
DISK_ONLY- Caches the results on disk
MEMORY_ONLY- Caches the results in memory. If not enough memory is available, records will be uncached.
MEMORY_ONLY_SER- Caches the results in memory in a serialized format. If not enough memory is available, records will be uncached.
MEMORY_AND_DISK- Caches the results first in memory and then spills to disk.
MEMORY_AND_DISK_SER- Caches the results first in memory in a serialized format and then spills to disk.
input(mandatory) (string): The name of the input mapping
partitions(mandatory) (integer): The number of output partitions
filter(optional) (type: string) (default: empty): An optional SQL filter expression that is applied after the transformation itself.
main- the only output of the mapping