This operator loads a block of data from a different dataset that has the matching partition key as that of the input block. This operator usually precedes a JOIN operator.
block2 = LOAD BLOCK FROM "dataset2location" MATCHING block1;
PRECONDITIONS: The two input datasets must have identical index.
COMBINE operator does a sorted merge (or union) of two input blocks by comparing the input sort columns.
combined = COMBINE block1, block2 SORTED ON memberId, country_sk;
PRECONDITIONS: All blocks must be sorted on the sort keys.
PIVOT operator creates multiple output (sub-)blocks for an input block based on the columns specified. Each output sub-block would have all the tuples for a distinct value of the pivot keys. The number of output blocks, therefore, is equal to the number of distinct pivot keys found in the input.
pivotedblock = PIVOT inputblock ON memberId;
PIVOT operator can be used in IN MEMORY mode where in it would store all the tuples in a pivoted sub-block in memory.
pivotedblock = PIVOT IN MEMORY inputblock ON memberId;
PRECONDITIONS: The pivot keys specified must be the prefix of the sort keys of the input block.