This also enables hash join and hash aggregation on ltree columns.
Tommy Pavlicek, reviewed by jian he
Discussion: https://postgr.es/m/CAEhP-W9ZEoHeaP_nKnPCVd_o1c3BAUvq1gWHrq8EbkNRiS9CvQ@mail.gmail.com
ltxtquery_op.o
EXTENSION = ltree
-DATA = ltree--1.1--1.2.sql ltree--1.1.sql ltree--1.0--1.1.sql
+DATA = ltree--1.2--1.3.sql ltree--1.1--1.2.sql ltree--1.1.sql \
+ ltree--1.0--1.1.sql
PGFILEDESC = "ltree - hierarchical label data type"
HEADERS = ltree.h
g.b.c.d.e
(1 row)
+-- Check that the hash_ltree() and hash_ltree_extended() function's lower
+-- 32 bits match when the seed is 0 and do not match when the seed != 0
+SELECT v as value, hash_ltree(v)::bit(32) as standard,
+ hash_ltree_extended(v, 0)::bit(32) as extended0,
+ hash_ltree_extended(v, 1)::bit(32) as extended1
+FROM (VALUES (NULL::ltree), (''::ltree), ('0'::ltree), ('0.1'::ltree),
+ ('0.1.2'::ltree), ('0'::ltree), ('0_asd.1_ASD'::ltree)) x(v)
+WHERE hash_ltree(v)::bit(32) != hash_ltree_extended(v, 0)::bit(32)
+ OR hash_ltree(v)::bit(32) = hash_ltree_extended(v, 1)::bit(32);
+ value | standard | extended0 | extended1
+-------+----------+-----------+-----------
+(0 rows)
+
CREATE TABLE ltreetest (t ltree);
\copy ltreetest FROM 'data/ltree.data'
+SELECT count(*) from ltreetest;
+ count
+-------
+ 1006
+(1 row)
+
SELECT * FROM ltreetest WHERE t < '12.3' order by t asc;
t
----------------------------------
(4 rows)
drop index tstidx;
+--- test hash index
+create index tstidx on ltreetest using hash (t);
+set enable_seqscan=off;
+set enable_bitmapscan=off;
+EXPLAIN (COSTS OFF)
+SELECT * FROM ltreetest WHERE t = '12.3' order by t asc;
+ QUERY PLAN
+--------------------------------------
+ Index Scan using tstidx on ltreetest
+ Index Cond: (t = '12.3'::ltree)
+(2 rows)
+
+SELECT * FROM ltreetest WHERE t = '12.3' order by t asc;
+ t
+------
+ 12.3
+(1 row)
+
+reset enable_seqscan;
+reset enable_bitmapscan;
+-- test hash aggregate
+set enable_hashagg=on;
+set enable_sort=off;
+EXPLAIN (COSTS OFF)
+SELECT count(*) FROM (
+SELECT t FROM (SELECT * FROM ltreetest UNION ALL SELECT * FROM ltreetest) t1 GROUP BY t
+) t2;
+ QUERY PLAN
+-----------------------------------------------------
+ Aggregate
+ -> HashAggregate
+ Group Key: ltreetest.t
+ -> Append
+ -> Seq Scan on ltreetest
+ -> Seq Scan on ltreetest ltreetest_1
+(6 rows)
+
+SELECT count(*) FROM (
+SELECT t FROM (SELECT * FROM ltreetest UNION ALL SELECT * FROM ltreetest) t1 GROUP BY t
+) t2;
+ count
+-------
+ 1006
+(1 row)
+
+reset enable_hashagg;
+reset enable_sort;
+drop index tstidx;
+-- test gist index
create index tstidx on ltreetest using gist (t gist_ltree_ops(siglen=0));
ERROR: value 0 out of bounds for option "siglen"
DETAIL: Valid values are between "4" and "2024".
--- /dev/null
+/* contrib/ltree/ltree--1.2--1.3.sql */
+
+-- complain if script is sourced in psql, rather than via ALTER EXTENSION
+\echo Use "ALTER EXTENSION ltree UPDATE TO '1.3'" to load this file. \quit
+
+CREATE FUNCTION hash_ltree(ltree)
+RETURNS integer
+AS 'MODULE_PATHNAME'
+LANGUAGE C STRICT IMMUTABLE PARALLEL SAFE;
+
+CREATE FUNCTION hash_ltree_extended(ltree, bigint)
+RETURNS bigint
+AS 'MODULE_PATHNAME'
+LANGUAGE C STRICT IMMUTABLE PARALLEL SAFE;
+
+CREATE OPERATOR CLASS hash_ltree_ops
+DEFAULT FOR TYPE ltree USING hash
+AS
+ OPERATOR 1 = ,
+ FUNCTION 1 hash_ltree(ltree),
+ FUNCTION 2 hash_ltree_extended(ltree, bigint);
+
+ALTER OPERATOR =(ltree, ltree) SET (HASHES);
# ltree extension
comment = 'data type for hierarchical tree-like structures'
-default_version = '1.2'
+default_version = '1.3'
module_pathname = '$libdir/ltree'
relocatable = true
trusted = true
#include "access/htup_details.h"
#include "catalog/pg_statistic.h"
+#include "common/hashfn.h"
#include "ltree.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
PG_FUNCTION_INFO_V1(ltree_ne);
PG_FUNCTION_INFO_V1(ltree_ge);
PG_FUNCTION_INFO_V1(ltree_gt);
+PG_FUNCTION_INFO_V1(hash_ltree);
+PG_FUNCTION_INFO_V1(hash_ltree_extended);
PG_FUNCTION_INFO_V1(nlevel);
PG_FUNCTION_INFO_V1(ltree_isparent);
PG_FUNCTION_INFO_V1(ltree_risparent);
PG_RETURN_BOOL(res != 0);
}
+/* Compute a hash for the ltree */
+Datum
+hash_ltree(PG_FUNCTION_ARGS)
+{
+ ltree *a = PG_GETARG_LTREE_P(0);
+ uint32 result = 1;
+ int an = a->numlevel;
+ ltree_level *al = LTREE_FIRST(a);
+
+ while (an > 0)
+ {
+ uint32 levelHash = DatumGetUInt32(hash_any((unsigned char *) al->name, al->len));
+
+ /*
+ * Combine hash values of successive elements by multiplying the
+ * current value by 31 and adding on the new element's hash value.
+ *
+ * This method is borrowed from hash_array(), which see for further
+ * commentary.
+ */
+ result = (result << 5) - result + levelHash;
+
+ an--;
+ al = LEVEL_NEXT(al);
+ }
+
+ PG_FREE_IF_COPY(a, 0);
+ PG_RETURN_UINT32(result);
+}
+
+/* Compute an extended hash for the ltree */
+Datum
+hash_ltree_extended(PG_FUNCTION_ARGS)
+{
+ ltree *a = PG_GETARG_LTREE_P(0);
+ const uint64 seed = PG_GETARG_INT64(1);
+ uint64 result = 1;
+ int an = a->numlevel;
+ ltree_level *al = LTREE_FIRST(a);
+
+ /*
+ * If the path has length zero, return 1 + seed to ensure that the low 32
+ * bits of the result match hash_ltree when the seed is 0, as required by
+ * the hash index support functions, but to also return a different value
+ * when there is a seed.
+ */
+ if (an == 0)
+ {
+ PG_FREE_IF_COPY(a, 0);
+ PG_RETURN_UINT64(result + seed);
+ }
+
+ while (an > 0)
+ {
+ uint64 levelHash = DatumGetUInt64(hash_any_extended((unsigned char *) al->name, al->len, seed));
+
+ result = (result << 5) - result + levelHash;
+
+ an--;
+ al = LEVEL_NEXT(al);
+ }
+
+ PG_FREE_IF_COPY(a, 0);
+ PG_RETURN_UINT64(result);
+}
+
Datum
nlevel(PG_FUNCTION_ARGS)
{
INSERT INTO test VALUES ('Top.Collections.Pictures.Astronomy.Astronauts');
CREATE INDEX path_gist_idx ON test USING gist(path);
CREATE INDEX path_idx ON test USING btree(path);
+CREATE INDEX path_hash_idx ON test USING hash(path);
install_data(
'ltree.control',
'ltree--1.0--1.1.sql',
- 'ltree--1.1--1.2.sql',
'ltree--1.1.sql',
+ 'ltree--1.1--1.2.sql',
+ 'ltree--1.2--1.3.sql',
kwargs: contrib_data_args,
)
SELECT '{ltree.asd, tree.awdfg}'::ltree[] ?@ 'tree & aWdfg@'::ltxtquery;
SELECT '{j.k.l.m, g.b.c.d.e}'::ltree[] ?~ 'A*@|g.b.c.d.e';
+-- Check that the hash_ltree() and hash_ltree_extended() function's lower
+-- 32 bits match when the seed is 0 and do not match when the seed != 0
+SELECT v as value, hash_ltree(v)::bit(32) as standard,
+ hash_ltree_extended(v, 0)::bit(32) as extended0,
+ hash_ltree_extended(v, 1)::bit(32) as extended1
+FROM (VALUES (NULL::ltree), (''::ltree), ('0'::ltree), ('0.1'::ltree),
+ ('0.1.2'::ltree), ('0'::ltree), ('0_asd.1_ASD'::ltree)) x(v)
+WHERE hash_ltree(v)::bit(32) != hash_ltree_extended(v, 0)::bit(32)
+ OR hash_ltree(v)::bit(32) = hash_ltree_extended(v, 1)::bit(32);
+
CREATE TABLE ltreetest (t ltree);
\copy ltreetest FROM 'data/ltree.data'
+SELECT count(*) from ltreetest;
+
SELECT * FROM ltreetest WHERE t < '12.3' order by t asc;
SELECT * FROM ltreetest WHERE t <= '12.3' order by t asc;
SELECT * FROM ltreetest WHERE t = '12.3' order by t asc;
SELECT * FROM ltreetest WHERE t ? '{23.*.1,23.*.2}' order by t asc;
drop index tstidx;
+
+--- test hash index
+
+create index tstidx on ltreetest using hash (t);
+set enable_seqscan=off;
+set enable_bitmapscan=off;
+
+EXPLAIN (COSTS OFF)
+SELECT * FROM ltreetest WHERE t = '12.3' order by t asc;
+SELECT * FROM ltreetest WHERE t = '12.3' order by t asc;
+
+reset enable_seqscan;
+reset enable_bitmapscan;
+
+-- test hash aggregate
+
+set enable_hashagg=on;
+set enable_sort=off;
+
+EXPLAIN (COSTS OFF)
+SELECT count(*) FROM (
+SELECT t FROM (SELECT * FROM ltreetest UNION ALL SELECT * FROM ltreetest) t1 GROUP BY t
+) t2;
+
+SELECT count(*) FROM (
+SELECT t FROM (SELECT * FROM ltreetest UNION ALL SELECT * FROM ltreetest) t1 GROUP BY t
+) t2;
+
+reset enable_hashagg;
+reset enable_sort;
+
+drop index tstidx;
+
+-- test gist index
+
create index tstidx on ltreetest using gist (t gist_ltree_ops(siglen=0));
create index tstidx on ltreetest using gist (t gist_ltree_ops(siglen=2025));
create index tstidx on ltreetest using gist (t gist_ltree_ops(siglen=2028));
<literal>>=</literal>, <literal>></literal>
</para>
</listitem>
+ <listitem>
+ <para>
+ Hash index over <type>ltree</type>:
+ <literal>=</literal>
+ </para>
+ </listitem>
+
<listitem>
<para>
GiST index over <type>ltree</type> (<literal>gist_ltree_ops</literal>
INSERT INTO test VALUES ('Top.Collections.Pictures.Astronomy.Astronauts');
CREATE INDEX path_gist_idx ON test USING GIST (path);
CREATE INDEX path_idx ON test USING BTREE (path);
+CREATE INDEX path_hash_idx ON test USING HASH (path);
</programlisting>
<para>
projects / postgresql.git / commitdiff