MURMUR_HASH3_64_V2

Description

Computes a singed 64-bit MurmurHash3 hash value. The unsigned version refer to murmur_hash3_u64_v2

The difference from MURMUR_HASH3_64 is: this version reuses the 128-bit processing function of MurmurHash3, outputting only the first 64-bit hash value, which is consistent with the standard library implementation.

Note: According to testing, the performance of xxhash_64 is approximately 2 times that of murmur_hash3_64. Therefore, when calculating hash values, it is recommended to use xxhash_64 instead of murmur_hash3_64.

Syntax

MURMUR_HASH3_64_V2( <str> [ , <str> ... ] )

Parameters

Parameter	Description
<str>	The value to be computed as a 64-bit MurmurHash3 hash

Return Value

Returns the 64-bit MurmurHash3 hash value of the input string.

Returns NULL if any parameter is NULL.

Examples

select murmur_hash3_64_v2(null), murmur_hash3_64_v2("hello"), murmur_hash3_64_v2("hello", "world");

+--------------------------+-----------------------------+--------------------------------------+
| murmur_hash3_64_v2(null) | murmur_hash3_64_v2("hello") | murmur_hash3_64_v2("hello", "world") |
+--------------------------+-----------------------------+--------------------------------------+
|                     NULL |        -3758069500696749310 |                  -662943091231200135 |
+--------------------------+-----------------------------+--------------------------------------+

-- The function outputs a signed 64-bit integer.
SELECT
    mmhash3_64_v2,
    mmhash3_u64_v2,
    i64_to_ui64 = mmhash3_u64_v2 AS is_equal
FROM (
    SELECT
        murmur_hash3_64_v2('1013199993_1756808272') AS mmhash3_64_v2,
        murmur_hash3_u64_v2('1013199993_1756808272') AS mmhash3_u64_v2,
        CAST(murmur_hash3_64_v2('1013199993_1756808272') AS LARGEINT) & 18446744073709551615 AS i64_to_ui64
) t;

+----------------------+----------------------+----------+
| mmhash3_64_v2        | mmhash3_u64_v2       | is_equal |
+----------------------+----------------------+----------+
| -2648103510258542450 | 15798640563451009166 |        1 |
+----------------------+----------------------+----------+