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ce773f230d
The IEEE 754 standard allows a wide variety of bit patterns for NaNs,
of which at least two ("NaN" and "-NaN") are pretty easy to produce
from SQL on most machines. This is problematic because our btree
comparison functions deem all NaNs to be equal, but our float hash
functions know nothing about NaNs and will happily produce varying
hash codes for them. That causes unexpected results from queries
that hash a column containing different NaN values. It could also
produce unexpected lookup failures when using a hash index on a
float column, i.e. "WHERE x = 'NaN'" will not find all the rows
it should.
To fix, special-case NaN in the float hash functions, not too much
unlike the existing special case that forces zero and minus zero
to hash the same. I arranged for the most vanilla sort of NaN
(that coming from the C99 NAN constant) to still have the same
hash code as before, to reduce the risk to existing hash indexes.
I dithered about whether to back-patch this into stable branches,
but ultimately decided to do so. It's a clear improvement for
queries that hash internally. If there is anybody who has -NaN
in a hash index, they'd be well advised to re-index after applying
this patch ... but the misbehavior if they don't will not be much
worse than the misbehavior they had before.
Per bug #17172 from Ma Liangzhu.
Discussion: https://postgr.es/m/17172-7505bea9e04e230f@postgresql.org
264 lines
13 KiB
SQL
264 lines
13 KiB
SQL
--
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-- Test hash functions
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--
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-- When the salt is 0, the extended hash function should produce a result
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-- whose low 32 bits match the standard hash function. When the salt is
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-- not 0, we should get a different result.
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--
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SELECT v as value, hashint2(v)::bit(32) as standard,
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hashint2extended(v, 0)::bit(32) as extended0,
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hashint2extended(v, 1)::bit(32) as extended1
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FROM (VALUES (0::int2), (1::int2), (17::int2), (42::int2)) x(v)
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WHERE hashint2(v)::bit(32) != hashint2extended(v, 0)::bit(32)
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OR hashint2(v)::bit(32) = hashint2extended(v, 1)::bit(32);
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SELECT v as value, hashint4(v)::bit(32) as standard,
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hashint4extended(v, 0)::bit(32) as extended0,
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hashint4extended(v, 1)::bit(32) as extended1
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FROM (VALUES (0), (1), (17), (42), (550273), (207112489)) x(v)
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WHERE hashint4(v)::bit(32) != hashint4extended(v, 0)::bit(32)
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OR hashint4(v)::bit(32) = hashint4extended(v, 1)::bit(32);
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SELECT v as value, hashint8(v)::bit(32) as standard,
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hashint8extended(v, 0)::bit(32) as extended0,
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hashint8extended(v, 1)::bit(32) as extended1
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FROM (VALUES (0), (1), (17), (42), (550273), (207112489)) x(v)
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WHERE hashint8(v)::bit(32) != hashint8extended(v, 0)::bit(32)
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OR hashint8(v)::bit(32) = hashint8extended(v, 1)::bit(32);
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SELECT v as value, hashfloat4(v)::bit(32) as standard,
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hashfloat4extended(v, 0)::bit(32) as extended0,
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hashfloat4extended(v, 1)::bit(32) as extended1
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FROM (VALUES (0), (1), (17), (42), (550273), (207112489)) x(v)
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WHERE hashfloat4(v)::bit(32) != hashfloat4extended(v, 0)::bit(32)
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OR hashfloat4(v)::bit(32) = hashfloat4extended(v, 1)::bit(32);
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SELECT v as value, hashfloat8(v)::bit(32) as standard,
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hashfloat8extended(v, 0)::bit(32) as extended0,
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hashfloat8extended(v, 1)::bit(32) as extended1
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FROM (VALUES (0), (1), (17), (42), (550273), (207112489)) x(v)
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WHERE hashfloat8(v)::bit(32) != hashfloat8extended(v, 0)::bit(32)
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OR hashfloat8(v)::bit(32) = hashfloat8extended(v, 1)::bit(32);
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SELECT v as value, hashoid(v)::bit(32) as standard,
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hashoidextended(v, 0)::bit(32) as extended0,
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hashoidextended(v, 1)::bit(32) as extended1
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FROM (VALUES (0), (1), (17), (42), (550273), (207112489)) x(v)
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WHERE hashoid(v)::bit(32) != hashoidextended(v, 0)::bit(32)
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OR hashoid(v)::bit(32) = hashoidextended(v, 1)::bit(32);
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SELECT v as value, hashchar(v)::bit(32) as standard,
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hashcharextended(v, 0)::bit(32) as extended0,
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hashcharextended(v, 1)::bit(32) as extended1
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FROM (VALUES (NULL::"char"), ('1'), ('x'), ('X'), ('p'), ('N')) x(v)
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WHERE hashchar(v)::bit(32) != hashcharextended(v, 0)::bit(32)
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OR hashchar(v)::bit(32) = hashcharextended(v, 1)::bit(32);
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SELECT v as value, hashname(v)::bit(32) as standard,
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hashnameextended(v, 0)::bit(32) as extended0,
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hashnameextended(v, 1)::bit(32) as extended1
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FROM (VALUES (NULL), ('PostgreSQL'), ('eIpUEtqmY89'), ('AXKEJBTK'),
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('muop28x03'), ('yi3nm0d73')) x(v)
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WHERE hashname(v)::bit(32) != hashnameextended(v, 0)::bit(32)
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OR hashname(v)::bit(32) = hashnameextended(v, 1)::bit(32);
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SELECT v as value, hashtext(v)::bit(32) as standard,
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hashtextextended(v, 0)::bit(32) as extended0,
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hashtextextended(v, 1)::bit(32) as extended1
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FROM (VALUES (NULL), ('PostgreSQL'), ('eIpUEtqmY89'), ('AXKEJBTK'),
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('muop28x03'), ('yi3nm0d73')) x(v)
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WHERE hashtext(v)::bit(32) != hashtextextended(v, 0)::bit(32)
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OR hashtext(v)::bit(32) = hashtextextended(v, 1)::bit(32);
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SELECT v as value, hashoidvector(v)::bit(32) as standard,
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hashoidvectorextended(v, 0)::bit(32) as extended0,
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hashoidvectorextended(v, 1)::bit(32) as extended1
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FROM (VALUES (NULL::oidvector), ('0 1 2 3 4'), ('17 18 19 20'),
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('42 43 42 45'), ('550273 550273 570274'),
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('207112489 207112499 21512 2155 372325 1363252')) x(v)
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WHERE hashoidvector(v)::bit(32) != hashoidvectorextended(v, 0)::bit(32)
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OR hashoidvector(v)::bit(32) = hashoidvectorextended(v, 1)::bit(32);
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SELECT v as value, hash_aclitem(v)::bit(32) as standard,
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hash_aclitem_extended(v, 0)::bit(32) as extended0,
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hash_aclitem_extended(v, 1)::bit(32) as extended1
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FROM (SELECT DISTINCT(relacl[1]) FROM pg_class LIMIT 10) x(v)
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WHERE hash_aclitem(v)::bit(32) != hash_aclitem_extended(v, 0)::bit(32)
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OR hash_aclitem(v)::bit(32) = hash_aclitem_extended(v, 1)::bit(32);
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SELECT v as value, hashmacaddr(v)::bit(32) as standard,
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hashmacaddrextended(v, 0)::bit(32) as extended0,
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hashmacaddrextended(v, 1)::bit(32) as extended1
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FROM (VALUES (NULL::macaddr), ('08:00:2b:01:02:04'), ('08:00:2b:01:02:04'),
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('e2:7f:51:3e:70:49'), ('d6:a9:4a:78:1c:d5'),
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('ea:29:b1:5e:1f:a5')) x(v)
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WHERE hashmacaddr(v)::bit(32) != hashmacaddrextended(v, 0)::bit(32)
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OR hashmacaddr(v)::bit(32) = hashmacaddrextended(v, 1)::bit(32);
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SELECT v as value, hashinet(v)::bit(32) as standard,
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hashinetextended(v, 0)::bit(32) as extended0,
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hashinetextended(v, 1)::bit(32) as extended1
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FROM (VALUES (NULL::inet), ('192.168.100.128/25'), ('192.168.100.0/8'),
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('172.168.10.126/16'), ('172.18.103.126/24'), ('192.188.13.16/32')) x(v)
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WHERE hashinet(v)::bit(32) != hashinetextended(v, 0)::bit(32)
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OR hashinet(v)::bit(32) = hashinetextended(v, 1)::bit(32);
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SELECT v as value, hash_numeric(v)::bit(32) as standard,
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hash_numeric_extended(v, 0)::bit(32) as extended0,
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hash_numeric_extended(v, 1)::bit(32) as extended1
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FROM (VALUES (0), (1.149484958), (17.149484958), (42.149484958),
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(149484958.550273), (2071124898672)) x(v)
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WHERE hash_numeric(v)::bit(32) != hash_numeric_extended(v, 0)::bit(32)
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OR hash_numeric(v)::bit(32) = hash_numeric_extended(v, 1)::bit(32);
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SELECT v as value, hashmacaddr8(v)::bit(32) as standard,
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hashmacaddr8extended(v, 0)::bit(32) as extended0,
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hashmacaddr8extended(v, 1)::bit(32) as extended1
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FROM (VALUES (NULL::macaddr8), ('08:00:2b:01:02:04:36:49'),
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('08:00:2b:01:02:04:f0:e8'), ('e2:7f:51:3e:70:49:16:29'),
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('d6:a9:4a:78:1c:d5:47:32'), ('ea:29:b1:5e:1f:a5')) x(v)
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WHERE hashmacaddr8(v)::bit(32) != hashmacaddr8extended(v, 0)::bit(32)
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OR hashmacaddr8(v)::bit(32) = hashmacaddr8extended(v, 1)::bit(32);
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SELECT v as value, hash_array(v)::bit(32) as standard,
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hash_array_extended(v, 0)::bit(32) as extended0,
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hash_array_extended(v, 1)::bit(32) as extended1
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FROM (VALUES ('{0}'::int4[]), ('{0,1,2,3,4}'), ('{17,18,19,20}'),
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('{42,34,65,98}'), ('{550273,590027, 870273}'),
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('{207112489, 807112489}')) x(v)
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WHERE hash_array(v)::bit(32) != hash_array_extended(v, 0)::bit(32)
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OR hash_array(v)::bit(32) = hash_array_extended(v, 1)::bit(32);
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-- array hashing with non-hashable element type
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SELECT v as value, hash_array(v)::bit(32) as standard
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FROM (VALUES ('{0}'::money[])) x(v);
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SELECT v as value, hash_array_extended(v, 0)::bit(32) as extended0
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FROM (VALUES ('{0}'::money[])) x(v);
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SELECT v as value, hashbpchar(v)::bit(32) as standard,
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hashbpcharextended(v, 0)::bit(32) as extended0,
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hashbpcharextended(v, 1)::bit(32) as extended1
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FROM (VALUES (NULL), ('PostgreSQL'), ('eIpUEtqmY89'), ('AXKEJBTK'),
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('muop28x03'), ('yi3nm0d73')) x(v)
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WHERE hashbpchar(v)::bit(32) != hashbpcharextended(v, 0)::bit(32)
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OR hashbpchar(v)::bit(32) = hashbpcharextended(v, 1)::bit(32);
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SELECT v as value, time_hash(v)::bit(32) as standard,
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time_hash_extended(v, 0)::bit(32) as extended0,
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time_hash_extended(v, 1)::bit(32) as extended1
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FROM (VALUES (NULL::time), ('11:09:59'), ('1:09:59'), ('11:59:59'),
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('7:9:59'), ('5:15:59')) x(v)
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WHERE time_hash(v)::bit(32) != time_hash_extended(v, 0)::bit(32)
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OR time_hash(v)::bit(32) = time_hash_extended(v, 1)::bit(32);
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SELECT v as value, timetz_hash(v)::bit(32) as standard,
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timetz_hash_extended(v, 0)::bit(32) as extended0,
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timetz_hash_extended(v, 1)::bit(32) as extended1
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FROM (VALUES (NULL::timetz), ('00:11:52.518762-07'), ('00:11:52.51762-08'),
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('00:11:52.62-01'), ('00:11:52.62+01'), ('11:59:59+04')) x(v)
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WHERE timetz_hash(v)::bit(32) != timetz_hash_extended(v, 0)::bit(32)
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OR timetz_hash(v)::bit(32) = timetz_hash_extended(v, 1)::bit(32);
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SELECT v as value, interval_hash(v)::bit(32) as standard,
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interval_hash_extended(v, 0)::bit(32) as extended0,
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interval_hash_extended(v, 1)::bit(32) as extended1
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FROM (VALUES (NULL::interval),
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('5 month 7 day 46 minutes'), ('1 year 7 day 46 minutes'),
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('1 year 7 month 20 day 46 minutes'), ('5 month'),
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('17 year 11 month 7 day 9 hours 46 minutes 5 seconds')) x(v)
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WHERE interval_hash(v)::bit(32) != interval_hash_extended(v, 0)::bit(32)
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OR interval_hash(v)::bit(32) = interval_hash_extended(v, 1)::bit(32);
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SELECT v as value, timestamp_hash(v)::bit(32) as standard,
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timestamp_hash_extended(v, 0)::bit(32) as extended0,
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timestamp_hash_extended(v, 1)::bit(32) as extended1
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FROM (VALUES (NULL::timestamp), ('2017-08-22 00:09:59.518762'),
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('2015-08-20 00:11:52.51762-08'),
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('2017-05-22 00:11:52.62-01'),
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('2013-08-22 00:11:52.62+01'), ('2013-08-22 11:59:59+04')) x(v)
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WHERE timestamp_hash(v)::bit(32) != timestamp_hash_extended(v, 0)::bit(32)
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OR timestamp_hash(v)::bit(32) = timestamp_hash_extended(v, 1)::bit(32);
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SELECT v as value, uuid_hash(v)::bit(32) as standard,
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uuid_hash_extended(v, 0)::bit(32) as extended0,
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uuid_hash_extended(v, 1)::bit(32) as extended1
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FROM (VALUES (NULL::uuid), ('a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11'),
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('5a9ba4ac-8d6f-11e7-bb31-be2e44b06b34'),
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('99c6705c-d939-461c-a3c9-1690ad64ed7b'),
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('7deed3ca-8d6f-11e7-bb31-be2e44b06b34'),
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('9ad46d4f-6f2a-4edd-aadb-745993928e1e')) x(v)
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WHERE uuid_hash(v)::bit(32) != uuid_hash_extended(v, 0)::bit(32)
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OR uuid_hash(v)::bit(32) = uuid_hash_extended(v, 1)::bit(32);
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SELECT v as value, pg_lsn_hash(v)::bit(32) as standard,
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pg_lsn_hash_extended(v, 0)::bit(32) as extended0,
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pg_lsn_hash_extended(v, 1)::bit(32) as extended1
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FROM (VALUES (NULL::pg_lsn), ('16/B374D84'), ('30/B374D84'),
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('255/B374D84'), ('25/B379D90'), ('900/F37FD90')) x(v)
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WHERE pg_lsn_hash(v)::bit(32) != pg_lsn_hash_extended(v, 0)::bit(32)
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OR pg_lsn_hash(v)::bit(32) = pg_lsn_hash_extended(v, 1)::bit(32);
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CREATE TYPE mood AS ENUM ('sad', 'ok', 'happy');
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SELECT v as value, hashenum(v)::bit(32) as standard,
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hashenumextended(v, 0)::bit(32) as extended0,
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hashenumextended(v, 1)::bit(32) as extended1
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FROM (VALUES ('sad'::mood), ('ok'), ('happy')) x(v)
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WHERE hashenum(v)::bit(32) != hashenumextended(v, 0)::bit(32)
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OR hashenum(v)::bit(32) = hashenumextended(v, 1)::bit(32);
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DROP TYPE mood;
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SELECT v as value, jsonb_hash(v)::bit(32) as standard,
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jsonb_hash_extended(v, 0)::bit(32) as extended0,
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jsonb_hash_extended(v, 1)::bit(32) as extended1
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FROM (VALUES (NULL::jsonb),
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('{"a": "aaa bbb ddd ccc", "b": ["eee fff ggg"], "c": {"d": "hhh iii"}}'),
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('{"foo": [true, "bar"], "tags": {"e": 1, "f": null}}'),
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('{"g": {"h": "value"}}')) x(v)
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WHERE jsonb_hash(v)::bit(32) != jsonb_hash_extended(v, 0)::bit(32)
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OR jsonb_hash(v)::bit(32) = jsonb_hash_extended(v, 1)::bit(32);
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SELECT v as value, hash_range(v)::bit(32) as standard,
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hash_range_extended(v, 0)::bit(32) as extended0,
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hash_range_extended(v, 1)::bit(32) as extended1
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FROM (VALUES (int4range(10, 20)), (int4range(23, 43)),
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(int4range(5675, 550273)),
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(int4range(550274, 1550274)), (int4range(1550275, 208112489))) x(v)
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WHERE hash_range(v)::bit(32) != hash_range_extended(v, 0)::bit(32)
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OR hash_range(v)::bit(32) = hash_range_extended(v, 1)::bit(32);
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SELECT v as value, hash_multirange(v)::bit(32) as standard,
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hash_multirange_extended(v, 0)::bit(32) as extended0,
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hash_multirange_extended(v, 1)::bit(32) as extended1
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FROM (VALUES ('{[10,20)}'::int4multirange), ('{[23, 43]}'::int4multirange),
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('{[5675, 550273)}'::int4multirange),
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('{[550274, 1550274)}'::int4multirange),
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('{[1550275, 208112489)}'::int4multirange)) x(v)
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WHERE hash_multirange(v)::bit(32) != hash_multirange_extended(v, 0)::bit(32)
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OR hash_multirange(v)::bit(32) = hash_multirange_extended(v, 1)::bit(32);
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CREATE TYPE hash_test_t1 AS (a int, b text);
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SELECT v as value, hash_record(v)::bit(32) as standard,
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hash_record_extended(v, 0)::bit(32) as extended0,
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hash_record_extended(v, 1)::bit(32) as extended1
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FROM (VALUES (row(1, 'aaa')::hash_test_t1, row(2, 'bbb'), row(-1, 'ccc'))) x(v)
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WHERE hash_record(v)::bit(32) != hash_record_extended(v, 0)::bit(32)
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OR hash_record(v)::bit(32) = hash_record_extended(v, 1)::bit(32);
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DROP TYPE hash_test_t1;
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-- record hashing with non-hashable field type
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CREATE TYPE hash_test_t2 AS (a money, b text);
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SELECT v as value, hash_record(v)::bit(32) as standard
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FROM (VALUES (row(1, 'aaa')::hash_test_t2)) x(v);
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SELECT v as value, hash_record_extended(v, 0)::bit(32) as extended0
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FROM (VALUES (row(1, 'aaa')::hash_test_t2)) x(v);
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DROP TYPE hash_test_t2;
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--
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-- Check special cases for specific data types
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--
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SELECT hashfloat4('0'::float4) = hashfloat4('-0'::float4) AS t;
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SELECT hashfloat4('NaN'::float4) = hashfloat4('-NaN'::float4) AS t;
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SELECT hashfloat8('0'::float8) = hashfloat8('-0'::float8) AS t;
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SELECT hashfloat8('NaN'::float8) = hashfloat8('-NaN'::float8) AS t;
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SELECT hashfloat4('NaN'::float4) = hashfloat8('NaN'::float8) AS t;
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