Skip to content

Commit 485f0aa

Browse files
tglsfdctglsfdc
committed
Add hash support functions and hash opclass for contrib/ltree.
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
1 parent 0997e0a commit 485f0aa

File tree

9 files changed

+221
-3
lines changed

9 files changed

+221
-3
lines changed

‎contrib/ltree/Makefile

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -14,7 +14,8 @@ OBJS = \
1414
ltxtquery_op.o
1515

1616
EXTENSION = ltree
17-
DATA = ltree--1.1--1.2.sql ltree--1.1.sql ltree--1.0--1.1.sql
17+
DATA = ltree--1.2--1.3.sql ltree--1.1--1.2.sql ltree--1.1.sql \
18+
ltree--1.0--1.1.sql
1819
PGFILEDESC = "ltree - hierarchical label data type"
1920

2021
HEADERS = ltree.h

‎contrib/ltree/expected/ltree.out

Lines changed: 68 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1433,8 +1433,27 @@ SELECT '{j.k.l.m, g.b.c.d.e}'::ltree[] ?~ 'A*@|g.b.c.d.e';
14331433
g.b.c.d.e
14341434
(1 row)
14351435

1436+
-- Check that the hash_ltree() and hash_ltree_extended() function's lower
1437+
-- 32 bits match when the seed is 0 and do not match when the seed != 0
1438+
SELECT v as value, hash_ltree(v)::bit(32) as standard,
1439+
hash_ltree_extended(v, 0)::bit(32) as extended0,
1440+
hash_ltree_extended(v, 1)::bit(32) as extended1
1441+
FROM (VALUES (NULL::ltree), (''::ltree), ('0'::ltree), ('0.1'::ltree),
1442+
('0.1.2'::ltree), ('0'::ltree), ('0_asd.1_ASD'::ltree)) x(v)
1443+
WHERE hash_ltree(v)::bit(32) != hash_ltree_extended(v, 0)::bit(32)
1444+
OR hash_ltree(v)::bit(32) = hash_ltree_extended(v, 1)::bit(32);
1445+
value | standard | extended0 | extended1
1446+
-------+----------+-----------+-----------
1447+
(0 rows)
1448+
14361449
CREATE TABLE ltreetest (t ltree);
14371450
\copy ltreetest FROM 'data/ltree.data'
1451+
SELECT count(*) from ltreetest;
1452+
count
1453+
-------
1454+
1006
1455+
(1 row)
1456+
14381457
SELECT * FROM ltreetest WHERE t < '12.3' order by t asc;
14391458
t
14401459
----------------------------------
@@ -7833,6 +7852,55 @@ SELECT * FROM ltreetest WHERE t ? '{23.*.1,23.*.2}' order by t asc;
78337852
(4 rows)
78347853

78357854
drop index tstidx;
7855+
--- test hash index
7856+
create index tstidx on ltreetest using hash (t);
7857+
set enable_seqscan=off;
7858+
set enable_bitmapscan=off;
7859+
EXPLAIN (COSTS OFF)
7860+
SELECT * FROM ltreetest WHERE t = '12.3' order by t asc;
7861+
QUERY PLAN
7862+
--------------------------------------
7863+
Index Scan using tstidx on ltreetest
7864+
Index Cond: (t = '12.3'::ltree)
7865+
(2 rows)
7866+
7867+
SELECT * FROM ltreetest WHERE t = '12.3' order by t asc;
7868+
t
7869+
------
7870+
12.3
7871+
(1 row)
7872+
7873+
reset enable_seqscan;
7874+
reset enable_bitmapscan;
7875+
-- test hash aggregate
7876+
set enable_hashagg=on;
7877+
set enable_sort=off;
7878+
EXPLAIN (COSTS OFF)
7879+
SELECT count(*) FROM (
7880+
SELECT t FROM (SELECT * FROM ltreetest UNION ALL SELECT * FROM ltreetest) t1 GROUP BY t
7881+
) t2;
7882+
QUERY PLAN
7883+
-----------------------------------------------------
7884+
Aggregate
7885+
-> HashAggregate
7886+
Group Key: ltreetest.t
7887+
-> Append
7888+
-> Seq Scan on ltreetest
7889+
-> Seq Scan on ltreetest ltreetest_1
7890+
(6 rows)
7891+
7892+
SELECT count(*) FROM (
7893+
SELECT t FROM (SELECT * FROM ltreetest UNION ALL SELECT * FROM ltreetest) t1 GROUP BY t
7894+
) t2;
7895+
count
7896+
-------
7897+
1006
7898+
(1 row)
7899+
7900+
reset enable_hashagg;
7901+
reset enable_sort;
7902+
drop index tstidx;
7903+
-- test gist index
78367904
create index tstidx on ltreetest using gist (t gist_ltree_ops(siglen=0));
78377905
ERROR: value 0 out of bounds for option "siglen"
78387906
DETAIL: Valid values are between "4" and "2024".

‎contrib/ltree/ltree--1.2--1.3.sql

Lines changed: 23 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,23 @@
1+
/* contrib/ltree/ltree--1.2--1.3.sql */
2+
3+
-- complain if script is sourced in psql, rather than via ALTER EXTENSION
4+
\echo Use "ALTER EXTENSION ltree UPDATE TO '1.3'" to load this file. \quit
5+
6+
CREATE FUNCTION hash_ltree(ltree)
7+
RETURNS integer
8+
AS 'MODULE_PATHNAME'
9+
LANGUAGE C STRICT IMMUTABLE PARALLEL SAFE;
10+
11+
CREATE FUNCTION hash_ltree_extended(ltree, bigint)
12+
RETURNS bigint
13+
AS 'MODULE_PATHNAME'
14+
LANGUAGE C STRICT IMMUTABLE PARALLEL SAFE;
15+
16+
CREATE OPERATOR CLASS hash_ltree_ops
17+
DEFAULT FOR TYPE ltree USING hash
18+
AS
19+
OPERATOR 1 = ,
20+
FUNCTION 1 hash_ltree(ltree),
21+
FUNCTION 2 hash_ltree_extended(ltree, bigint);
22+
23+
ALTER OPERATOR =(ltree, ltree) SET (HASHES);

‎contrib/ltree/ltree.control

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,6 +1,6 @@
11
# ltree extension
22
comment = 'data type for hierarchical tree-like structures'
3-
default_version = '1.2'
3+
default_version = '1.3'
44
module_pathname = '$libdir/ltree'
55
relocatable = true
66
trusted = true

‎contrib/ltree/ltree_op.c

Lines changed: 69 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -9,6 +9,7 @@
99

1010
#include "access/htup_details.h"
1111
#include "catalog/pg_statistic.h"
12+
#include "common/hashfn.h"
1213
#include "ltree.h"
1314
#include "utils/builtins.h"
1415
#include "utils/lsyscache.h"
@@ -24,6 +25,8 @@ PG_FUNCTION_INFO_V1(ltree_eq);
2425
PG_FUNCTION_INFO_V1(ltree_ne);
2526
PG_FUNCTION_INFO_V1(ltree_ge);
2627
PG_FUNCTION_INFO_V1(ltree_gt);
28+
PG_FUNCTION_INFO_V1(hash_ltree);
29+
PG_FUNCTION_INFO_V1(hash_ltree_extended);
2730
PG_FUNCTION_INFO_V1(nlevel);
2831
PG_FUNCTION_INFO_V1(ltree_isparent);
2932
PG_FUNCTION_INFO_V1(ltree_risparent);
@@ -129,6 +132,72 @@ ltree_ne(PG_FUNCTION_ARGS)
129132
PG_RETURN_BOOL(res != 0);
130133
}
131134

135+
/* Compute a hash for the ltree */
136+
Datum
137+
hash_ltree(PG_FUNCTION_ARGS)
138+
{
139+
ltree *a = PG_GETARG_LTREE_P(0);
140+
uint32 result = 1;
141+
int an = a->numlevel;
142+
ltree_level *al = LTREE_FIRST(a);
143+
144+
while (an > 0)
145+
{
146+
uint32 levelHash = DatumGetUInt32(hash_any((unsigned char *) al->name, al->len));
147+
148+
/*
149+
* Combine hash values of successive elements by multiplying the
150+
* current value by 31 and adding on the new element's hash value.
151+
*
152+
* This method is borrowed from hash_array(), which see for further
153+
* commentary.
154+
*/
155+
result = (result << 5) - result + levelHash;
156+
157+
an--;
158+
al = LEVEL_NEXT(al);
159+
}
160+
161+
PG_FREE_IF_COPY(a, 0);
162+
PG_RETURN_UINT32(result);
163+
}
164+
165+
/* Compute an extended hash for the ltree */
166+
Datum
167+
hash_ltree_extended(PG_FUNCTION_ARGS)
168+
{
169+
ltree *a = PG_GETARG_LTREE_P(0);
170+
const uint64 seed = PG_GETARG_INT64(1);
171+
uint64 result = 1;
172+
int an = a->numlevel;
173+
ltree_level *al = LTREE_FIRST(a);
174+
175+
/*
176+
* If the path has length zero, return 1 + seed to ensure that the low 32
177+
* bits of the result match hash_ltree when the seed is 0, as required by
178+
* the hash index support functions, but to also return a different value
179+
* when there is a seed.
180+
*/
181+
if (an == 0)
182+
{
183+
PG_FREE_IF_COPY(a, 0);
184+
PG_RETURN_UINT64(result + seed);
185+
}
186+
187+
while (an > 0)
188+
{
189+
uint64 levelHash = DatumGetUInt64(hash_any_extended((unsigned char *) al->name, al->len, seed));
190+
191+
result = (result << 5) - result + levelHash;
192+
193+
an--;
194+
al = LEVEL_NEXT(al);
195+
}
196+
197+
PG_FREE_IF_COPY(a, 0);
198+
PG_RETURN_UINT64(result);
199+
}
200+
132201
Datum
133202
nlevel(PG_FUNCTION_ARGS)
134203
{

‎contrib/ltree/ltreetest.sql

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -19,3 +19,4 @@ INSERT INTO test VALUES ('Top.Collections.Pictures.Astronomy.Galaxies');
1919
INSERT INTO test VALUES ('Top.Collections.Pictures.Astronomy.Astronauts');
2020
CREATE INDEX path_gist_idx ON test USING gist(path);
2121
CREATE INDEX path_idx ON test USING btree(path);
22+
CREATE INDEX path_hash_idx ON test USING hash(path);

‎contrib/ltree/meson.build

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -30,8 +30,9 @@ contrib_targets += ltree
3030
install_data(
3131
'ltree.control',
3232
'ltree--1.0--1.1.sql',
33-
'ltree--1.1--1.2.sql',
3433
'ltree--1.1.sql',
34+
'ltree--1.1--1.2.sql',
35+
'ltree--1.2--1.3.sql',
3536
kwargs: contrib_data_args,
3637
)
3738

‎contrib/ltree/sql/ltree.sql

Lines changed: 47 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -282,9 +282,21 @@ SELECT ('{3456,1.2.3.4}'::ltree[] ?<@ '1.2.5') is null;
282282
SELECT '{ltree.asd, tree.awdfg}'::ltree[] ?@ 'tree & aWdfg@'::ltxtquery;
283283
SELECT '{j.k.l.m, g.b.c.d.e}'::ltree[] ?~ 'A*@|g.b.c.d.e';
284284

285+
-- Check that the hash_ltree() and hash_ltree_extended() function's lower
286+
-- 32 bits match when the seed is 0 and do not match when the seed != 0
287+
SELECT v as value, hash_ltree(v)::bit(32) as standard,
288+
hash_ltree_extended(v, 0)::bit(32) as extended0,
289+
hash_ltree_extended(v, 1)::bit(32) as extended1
290+
FROM (VALUES (NULL::ltree), (''::ltree), ('0'::ltree), ('0.1'::ltree),
291+
('0.1.2'::ltree), ('0'::ltree), ('0_asd.1_ASD'::ltree)) x(v)
292+
WHERE hash_ltree(v)::bit(32) != hash_ltree_extended(v, 0)::bit(32)
293+
OR hash_ltree(v)::bit(32) = hash_ltree_extended(v, 1)::bit(32);
294+
285295
CREATE TABLE ltreetest (t ltree);
286296
\copy ltreetest FROM 'data/ltree.data'
287297

298+
SELECT count(*) from ltreetest;
299+
288300
SELECT * FROM ltreetest WHERE t < '12.3' order by t asc;
289301
SELECT * FROM ltreetest WHERE t <= '12.3' order by t asc;
290302
SELECT * FROM ltreetest WHERE t = '12.3' order by t asc;
@@ -329,6 +341,41 @@ SELECT * FROM ltreetest WHERE t ~ '23.*.2' order by t asc;
329341
SELECT * FROM ltreetest WHERE t ? '{23.*.1,23.*.2}' order by t asc;
330342

331343
drop index tstidx;
344+
345+
--- test hash index
346+
347+
create index tstidx on ltreetest using hash (t);
348+
set enable_seqscan=off;
349+
set enable_bitmapscan=off;
350+
351+
EXPLAIN (COSTS OFF)
352+
SELECT * FROM ltreetest WHERE t = '12.3' order by t asc;
353+
SELECT * FROM ltreetest WHERE t = '12.3' order by t asc;
354+
355+
reset enable_seqscan;
356+
reset enable_bitmapscan;
357+
358+
-- test hash aggregate
359+
360+
set enable_hashagg=on;
361+
set enable_sort=off;
362+
363+
EXPLAIN (COSTS OFF)
364+
SELECT count(*) FROM (
365+
SELECT t FROM (SELECT * FROM ltreetest UNION ALL SELECT * FROM ltreetest) t1 GROUP BY t
366+
) t2;
367+
368+
SELECT count(*) FROM (
369+
SELECT t FROM (SELECT * FROM ltreetest UNION ALL SELECT * FROM ltreetest) t1 GROUP BY t
370+
) t2;
371+
372+
reset enable_hashagg;
373+
reset enable_sort;
374+
375+
drop index tstidx;
376+
377+
-- test gist index
378+
332379
create index tstidx on ltreetest using gist (t gist_ltree_ops(siglen=0));
333380
create index tstidx on ltreetest using gist (t gist_ltree_ops(siglen=2025));
334381
create index tstidx on ltreetest using gist (t gist_ltree_ops(siglen=2028));

‎doc/src/sgml/ltree.sgml

Lines changed: 8 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -623,6 +623,13 @@ Europe &amp; Russia*@ &amp; !Transportation
623623
<literal>&gt;=</literal>, <literal>&gt;</literal>
624624
</para>
625625
</listitem>
626+
<listitem>
627+
<para>
628+
Hash index over <type>ltree</type>:
629+
<literal>=</literal>
630+
</para>
631+
</listitem>
632+
626633
<listitem>
627634
<para>
628635
GiST index over <type>ltree</type> (<literal>gist_ltree_ops</literal>
@@ -712,6 +719,7 @@ INSERT INTO test VALUES ('Top.Collections.Pictures.Astronomy.Galaxies');
712719
INSERT INTO test VALUES ('Top.Collections.Pictures.Astronomy.Astronauts');
713720
CREATE INDEX path_gist_idx ON test USING GIST (path);
714721
CREATE INDEX path_idx ON test USING BTREE (path);
722+
CREATE INDEX path_hash_idx ON test USING HASH (path);
715723
</programlisting>
716724

717725
<para>

0 commit comments

Comments
 (0)
pFad - Phonifier reborn

Pfad - The Proxy pFad of © 2024 Garber Painting. All rights reserved.

Note: This service is not intended for secure transactions such as banking, social media, email, or purchasing. Use at your own risk. We assume no liability whatsoever for broken pages.


Alternative Proxies:

Alternative Proxy

pFad Proxy

pFad v3 Proxy

pFad v4 Proxy