Hash Functions
hll_hash_boolean(bool)
Description: Hashes data of the bool type.
Return type: hll_hashval
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SELECT hll_hash_boolean(FALSE); hll_hash_boolean --------------------- 5048724184180415669 (1 row) |
hll_hash_boolean(bool, int32)
Description: Configures a hash seed (that is, change the hash policy) and hashes data of the bool type.
Return type: hll_hashval
Example:
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SELECT hll_hash_boolean(FALSE, 10); hll_hash_boolean -------------------- 391264977436098630 (1 row) |
hll_hash_smallint(smallint)
Description: Hashes data of the smallint type.
Return type: hll_hashval
Example:
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SELECT hll_hash_smallint(100::smallint); hll_hash_smallint --------------------- 4631120266694327276 (1 row) |
If parameters with the same numeric value are hashed using different data types, the data will differ, because hash functions select different calculation policies for each type.
hll_hash_smallint(smallint, int32)
Description: Configures a hash seed (that is, change the hash policy) and hashes data of the smallint type.
Return type: hll_hashval
Example:
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SELECT hll_hash_smallint(100::smallint, 10); hll_hash_smallint --------------------- 8349353095166695771 (1 row) |
hll_hash_integer(integer)
Description: Hashes data of the integer type.
Return type: hll_hashval
Example:
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SELECT hll_hash_integer(0); hll_hash_integer ---------------------- -3485513579396041028 (1 row) |
hll_hash_integer(integer, int32)
Description: Hashes data of the integer type and configures a hash seed (that is, change the hash policy).
Return type: hll_hashval
Example:
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SELECT hll_hash_integer(0, 10); hll_hash_integer -------------------- 183371090322255134 (1 row) |
hll_hash_bigint(bigint)
Description: Hashes data of the bigint type.
Return type: hll_hashval
Example:
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SELECT hll_hash_bigint(100::bigint); hll_hash_bigint --------------------- 8349353095166695771 (1 row) |
hll_hash_bigint(bigint, int32)
Description: Hashes data of the bigint type and configures a hash seed (that is, change the hash policy).
Return type: hll_hashval
Example:
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SELECT hll_hash_bigint(100::bigint, 10); hll_hash_bigint --------------------- 4631120266694327276 (1 row) |
hll_hash_bytea(bytea)
Description: Hashes data of the bytea type.
Return type: hll_hashval
Example:
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SELECT hll_hash_bytea(E'\\x'); hll_hash_bytea ---------------- 0 (1 row) |
hll_hash_bytea(bytea, int32)
Description: Hashes data of the bytea type and configures a hash seed (that is, change the hash policy).
Return type: hll_hashval
Example:
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SELECT hll_hash_bytea(E'\\x', 10); hll_hash_bytea --------------------- 6574525721897061910 (1 row) |
hll_hash_text(text)
Description: Hashes data of the text type.
Return type: hll_hashval
Example:
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SELECT hll_hash_text('AB'); hll_hash_text --------------------- 5365230931951287672 (1 row) |
hll_hash_text(text, int32)
Description: Hashes data of the text type and configures a hash seed (that is, change the hash policy).
Return type: hll_hashval
Example:
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SELECT hll_hash_text('AB', 10); hll_hash_text --------------------- 7680762839921155903 (1 row) |
hll_hash_any(anytype)
Description: Hashes data of any type.
Return type: hll_hashval
Example:
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SELECT hll_hash_any(1); hll_hash_any ---------------------- -8604791237420463362 (1 row) SELECT hll_hash_any('08:00:2b:01:02:03'::macaddr); hll_hash_any ---------------------- -4883882473551067169 (1 row) |
hll_hash_any(anytype, int32)
Description: Hashes data of any type and configures a hash seed (that is, change the hash policy).
Return type: hll_hashval
Example:
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SELECT hll_hash_any(1, 10); hll_hash_any ---------------------- -1478847531811254870 (1 row) |
hll_hashval_eq(hll_hashval, hll_hashval)
Description: Compares two pieces of data of the hll_hashval type to check whether they are the same.
Return type: bool
Example:
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SELECT hll_hashval_eq(hll_hash_integer(1), hll_hash_integer(1)); hll_hashval_eq ---------------- t (1 row) |
hll_hashval_ne(hll_hashval, hll_hashval)
Description: Compares two pieces of data of the hll_hashval type to check whether they are different.
Return type: bool
Example:
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SELECT hll_hashval_ne(hll_hash_integer(1), hll_hash_integer(1)); hll_hashval_ne ---------------- f (1 row) |
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