DISTINCT_COUNT_OFF_HEAP

This section contains reference documentation for the DISTINCT_COUNT_OFF_HEAP function.

Returns the count of distinct values. The values are stored using off-heap memory.

Signature

DISTINCT_COUNT_OFF_HEAP(col[, params])

• col (required): Name of the column to aggregate on.

• params (optional): Semicolon-separated parameter key-value pairs:

  • initialCapacity: The initial capacity of the set for non-dictionary-encoded case (default 10000).

  • hashbits: Number of bits for murmur3: 32/64/128 (default 64)

• Example: DISTINCT_COUNT_OFF_HEAP(col, 'initialCapacity=100000;hashbits=128')

Note

• For variable length data types such as STRING and BYTES, murmur3 hash values are used to represent the values.

• Currently it only supports aggregate without group-by. For MV column, it only supports fixes lengh types.