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Add prefix operator for TEXT type. 

The prefix operator along with SP-GiST indexes can be used as an alternative
for LIKE 'word%' commands  and it doesn't have a limitation of string/prefix
length as B-Tree has.

Bump catalog version

Author: Ildus Kurbangaliev with some editorization by me
Review by: Arthur Zakirov, Alexander Korotkov, and me
Discussion: https://www.postgresql.org/message-id/flat/20180202180327.222b04b3@wp.localdomain
This commit is contained in:
Teodor Sigaev 2018-04-03 19:46:45 +03:00
parent 4ab2999815
commit 710d90da1f
14 changed files with 189 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
doc/src/sgml/func.sgml
View File

@ -2274,6 +2274,21 @@
<entry><literal>ph</literal></entry>
</row>
<row>
<entry>
<indexterm>
<primary>starts_with</primary>
</indexterm>
<literal><function>starts_with(<parameter>string</parameter>, <parameter>prefix</parameter>)</function></literal>
</entry>
<entry><type>bool</type></entry>
<entry>
Returns true if <parameter>string</parameter> starts with <parameter>prefix</parameter>.
</entry>
<entry><literal>starts_with('alphabet', 'alph')</literal></entry>
<entry><literal>t</literal></entry>
</row>
<row>
<entry>
<indexterm>
@ -4033,6 +4048,12 @@ cast(-44 as bit(12)) <lineannotation>111111010100</lineannotation>
ILIKE</function>, respectively. All of these operators are
<productname>PostgreSQL</productname>-specific.
</para>
<para>
There is also the prefix operator <literal>^@</literal> and corresponding
<function>starts_with</function> function which covers cases when only
searching by beginning of the string is needed.
</para>
</sect2>

1
doc/src/sgml/spgist.sgml
View File

@ -161,6 +161,7 @@
<literal>~&lt;~</literal>
<literal>~&gt;=~</literal>
<literal>~&gt;~</literal>
<literal>^@</literal>
</entry>
</row>
<row>

43
src/backend/access/spgist/spgtextproc.c
View File

@ -67,6 +67,20 @@
*/
#define SPGIST_MAX_PREFIX_LENGTH Max((int) (BLCKSZ - 258 * 16 - 100), 32)
/*
* Strategy for collation aware operator on text is equal to btree strategy
* plus value of 10.
*
* Current collation aware strategies and their corresponding btree strategies:
* 11 BTLessStrategyNumber
* 12 BTLessEqualStrategyNumber
* 14 BTGreaterEqualStrategyNumber
* 15 BTGreaterStrategyNumber
*/
#define SPG_STRATEGY_ADDITION (10)
#define SPG_IS_COLLATION_AWARE_STRATEGY(s) ((s) > SPG_STRATEGY_ADDITION \
&& (s) != RTPrefixStrategyNumber)
/* Struct for sorting values in picksplit */
typedef struct spgNodePtr
{
@ -496,10 +510,10 @@ spg_text_inner_consistent(PG_FUNCTION_ARGS)
* well end with a partial multibyte character, so that applying
* any encoding-sensitive test to it would be risky anyhow.)
*/
if (strategy > 10)
if (SPG_IS_COLLATION_AWARE_STRATEGY(strategy))
{
if (collate_is_c)
strategy -= 10;
strategy -= SPG_STRATEGY_ADDITION;
else
continue;
}
@ -526,6 +540,10 @@ spg_text_inner_consistent(PG_FUNCTION_ARGS)
if (r < 0)
res = false;
break;
case RTPrefixStrategyNumber:
if (r != 0)
res = false;
break;
default:
elog(ERROR, "unrecognized strategy number: %d",
in->scankeys[j].sk_strategy);
@ -605,10 +623,27 @@ spg_text_leaf_consistent(PG_FUNCTION_ARGS)
int queryLen = VARSIZE_ANY_EXHDR(query);
int r;
if (strategy > 10)
if (strategy == RTPrefixStrategyNumber)
{
/*
* if level >= length of query then reconstrValue is began with
* query (prefix) string and we don't need to check it again.
*/
res = (level >= queryLen) ||
DatumGetBool(DirectFunctionCall2(text_starts_with,
out->leafValue, PointerGetDatum(query)));
if (!res) /* no need to consider remaining conditions */
break;
continue;
}
if (SPG_IS_COLLATION_AWARE_STRATEGY(strategy))
{
/* Collation-aware comparison */
strategy -= 10;
strategy -= SPG_STRATEGY_ADDITION;
/* If asserts enabled, verify encoding of reconstructed string */
Assert(pg_verifymbstr(fullValue, fullLen, false));

33
src/backend/utils/adt/selfuncs.c
View File

@ -1488,6 +1488,16 @@ likesel(PG_FUNCTION_ARGS)
}
/*
* prefixsel - selectivity of prefix operator
*/
Datum
prefixsel(PG_FUNCTION_ARGS)
{
PG_RETURN_FLOAT8(patternsel(fcinfo, Pattern_Type_Prefix, false));
}
/*
*
* iclikesel - Selectivity of ILIKE pattern match.
*/
Datum
@ -2906,6 +2916,15 @@ likejoinsel(PG_FUNCTION_ARGS)
PG_RETURN_FLOAT8(patternjoinsel(fcinfo, Pattern_Type_Like, false));
}
/*
* prefixjoinsel - Join selectivity of prefix operator
*/
Datum
prefixjoinsel(PG_FUNCTION_ARGS)
{
PG_RETURN_FLOAT8(patternjoinsel(fcinfo, Pattern_Type_Prefix, false));
}
/*
* iclikejoinsel - Join selectivity of ILIKE pattern match.
*/
@ -5947,6 +5966,20 @@ pattern_fixed_prefix(Const *patt, Pattern_Type ptype, Oid collation,
result = regex_fixed_prefix(patt, true, collation,
prefix, rest_selec);
break;
case Pattern_Type_Prefix:
/* Prefix type work is trivial. */
result = Pattern_Prefix_Partial;
*rest_selec = 1.0; /* all */
*prefix = makeConst(patt->consttype,
patt->consttypmod,
patt->constcollid,
patt->constlen,
datumCopy(patt->constvalue,
patt->constbyval,
patt->constlen),
patt->constisnull,
patt->constbyval);
break;
default:
elog(ERROR, "unrecognized ptype: %d", (int) ptype);
result = Pattern_Prefix_None; /* keep compiler quiet */

28
src/backend/utils/adt/varlena.c
View File

@ -1761,6 +1761,34 @@ text_ge(PG_FUNCTION_ARGS)
PG_RETURN_BOOL(result);
}
Datum
text_starts_with(PG_FUNCTION_ARGS)
{
Datum arg1 = PG_GETARG_DATUM(0);
Datum arg2 = PG_GETARG_DATUM(1);
bool result;
Size len1,
len2;
len1 = toast_raw_datum_size(arg1);
len2 = toast_raw_datum_size(arg2);
if (len2 > len1)
result = false;
else
{
text *targ1 = DatumGetTextPP(arg1);
text *targ2 = DatumGetTextPP(arg2);
result = (memcmp(VARDATA_ANY(targ1), VARDATA_ANY(targ2),
VARSIZE_ANY_EXHDR(targ2)) == 0);
PG_FREE_IF_COPY(targ1, 0);
PG_FREE_IF_COPY(targ2, 1);
}
PG_RETURN_BOOL(result);
}
Datum
bttextcmp(PG_FUNCTION_ARGS)
{

3
src/include/access/stratnum.h
View File

@ -68,8 +68,9 @@ typedef uint16 StrategyNumber;
#define RTSubEqualStrategyNumber 25 /* for inet <<= */
#define RTSuperStrategyNumber 26 /* for inet << */
#define RTSuperEqualStrategyNumber 27 /* for inet >>= */
#define RTPrefixStrategyNumber 28 /* for text ^@ */
#define RTMaxStrategyNumber 27
#define RTMaxStrategyNumber 28
#endif /* STRATNUM_H */

2
src/include/catalog/catversion.h
View File

@ -53,6 +53,6 @@
*/
/* yyyymmddN */
#define CATALOG_VERSION_NO 201803311
#define CATALOG_VERSION_NO 201804031
#endif

1
src/include/catalog/pg_amop.h
View File

@ -799,6 +799,7 @@ DATA(insert ( 4017 25 25 11 s 664 4000 0 ));
DATA(insert ( 4017 25 25 12 s 665 4000 0 ));
DATA(insert ( 4017 25 25 14 s 667 4000 0 ));
DATA(insert ( 4017 25 25 15 s 666 4000 0 ));
DATA(insert ( 4017 25 25 28 s 3877 4000 0 ));
/*
* btree jsonb_ops

2
src/include/catalog/pg_operator.h
View File

@ -134,6 +134,8 @@ DESCR("less than");
DATA(insert OID = 98 ( "=" PGNSP PGUID b t t 25 25 16 98 531 texteq eqsel eqjoinsel ));
DESCR("equal");
#define TextEqualOperator 98
DATA(insert OID = 3877 ( "^@" PGNSP PGUID b f f 25 25 16 0 0 starts_with prefixsel prefixjoinsel ));
DESCR("starts with");
DATA(insert OID = 349 ( "||" PGNSP PGUID b f f 2277 2283 2277 0 0 array_append - - ));
DESCR("append element onto end of array");

5
src/include/catalog/pg_proc.h
View File

@ -209,6 +209,7 @@ DATA(insert OID = 64 ( int2lt PGNSP PGUID 12 1 0 0 0 f f t t f i s 2 0 16
DATA(insert OID = 65 ( int4eq PGNSP PGUID 12 1 0 0 0 f f t t f i s 2 0 16 "23 23" _null_ _null_ _null_ _null_ _null_ int4eq _null_ _null_ _null_ ));
DATA(insert OID = 66 ( int4lt PGNSP PGUID 12 1 0 0 0 f f t t f i s 2 0 16 "23 23" _null_ _null_ _null_ _null_ _null_ int4lt _null_ _null_ _null_ ));
DATA(insert OID = 67 ( texteq PGNSP PGUID 12 1 0 0 0 f f t t f i s 2 0 16 "25 25" _null_ _null_ _null_ _null_ _null_ texteq _null_ _null_ _null_ ));
DATA(insert OID = 3696 ( starts_with PGNSP PGUID 12 1 0 0 0 f f t t f i s 2 0 16 "25 25" _null_ _null_ _null_ _null_ _null_ text_starts_with _null_ _null_ _null_ ));
DATA(insert OID = 68 ( xideq PGNSP PGUID 12 1 0 0 0 f f t t f i s 2 0 16 "28 28" _null_ _null_ _null_ _null_ _null_ xideq _null_ _null_ _null_ ));
DATA(insert OID = 3308 ( xidneq PGNSP PGUID 12 1 0 0 0 f f t t f i s 2 0 16 "28 28" _null_ _null_ _null_ _null_ _null_ xidneq _null_ _null_ _null_ ));
DATA(insert OID = 69 ( cideq PGNSP PGUID 12 1 0 0 0 f f t t f i s 2 0 16 "29 29" _null_ _null_ _null_ _null_ _null_ cideq _null_ _null_ _null_ ));
@ -2584,6 +2585,10 @@ DATA(insert OID = 1828 ( nlikejoinsel PGNSP PGUID 12 1 0 0 0 f f f t f s s 5 0
DESCR("join selectivity of NOT LIKE");
DATA(insert OID = 1829 ( icregexnejoinsel PGNSP PGUID 12 1 0 0 0 f f f t f s s 5 0 701 "2281 26 2281 21 2281" _null_ _null_ _null_ _null_ _null_ icregexnejoinsel _null_ _null_ _null_ ));
DESCR("join selectivity of case-insensitive regex non-match");
DATA(insert OID = 3437 ( prefixsel PGNSP PGUID 12 1 0 0 0 f f f t f s s 4 0 701 "2281 26 2281 23" _null_ _null_ _null_ _null_ _null_ prefixsel _null_ _null_ _null_ ));
DESCR("restriction selectivity of exact prefix");
DATA(insert OID = 3438 ( prefixjoinsel PGNSP PGUID 12 1 0 0 0 f f f t f s s 5 0 701 "2281 26 2281 21 2281" _null_ _null_ _null_ _null_ _null_ prefixjoinsel _null_ _null_ _null_ ));
DESCR("join selectivity of exact prefix");
/* Aggregate-related functions */
DATA(insert OID = 1830 ( float8_avg PGNSP PGUID 12 1 0 0 0 f f f t f i s 1 0 701 "1022" _null_ _null_ _null_ _null_ _null_ float8_avg _null_ _null_ _null_ ));

7
src/include/utils/selfuncs.h
View File

@ -87,8 +87,11 @@ typedef struct VariableStatData
typedef enum
{
Pattern_Type_Like, Pattern_Type_Like_IC,
Pattern_Type_Regex, Pattern_Type_Regex_IC
Pattern_Type_Like,
Pattern_Type_Like_IC,
Pattern_Type_Regex,
Pattern_Type_Regex_IC,
Pattern_Type_Prefix
} Pattern_Type;
typedef enum

38
src/test/regress/expected/create_index.out
View File

@ -372,6 +372,12 @@ SELECT count(*) FROM radix_text_tbl WHERE t ~>~ 'Worth
48
(1 row)
SELECT count(*) FROM radix_text_tbl WHERE t ^@ 'Worth';
count
-------
2
(1 row)
SELECT * FROM gpolygon_tbl ORDER BY f1 <-> '(0,0)'::point LIMIT 10;
f1
-------------------------------------------------
@ -1182,6 +1188,21 @@ SELECT count(*) FROM radix_text_tbl WHERE t ~>~ 'Worth
48
(1 row)
EXPLAIN (COSTS OFF)
SELECT count(*) FROM radix_text_tbl WHERE t ^@ 'Worth';
QUERY PLAN
------------------------------------------------------------
Aggregate
-> Index Only Scan using sp_radix_ind on radix_text_tbl
Index Cond: (t ^@ 'Worth'::text)
(3 rows)
SELECT count(*) FROM radix_text_tbl WHERE t ^@ 'Worth';
count
-------
2
(1 row)
EXPLAIN (COSTS OFF)
SELECT * FROM gpolygon_tbl ORDER BY f1 <-> '(0,0)'::point LIMIT 10;
QUERY PLAN
@ -1763,6 +1784,23 @@ SELECT count(*) FROM radix_text_tbl WHERE t ~>~ 'Worth
48
(1 row)
EXPLAIN (COSTS OFF)
SELECT count(*) FROM radix_text_tbl WHERE t ^@ 'Worth';
QUERY PLAN
------------------------------------------------
Aggregate
-> Bitmap Heap Scan on radix_text_tbl
Recheck Cond: (t ^@ 'Worth'::text)
-> Bitmap Index Scan on sp_radix_ind
Index Cond: (t ^@ 'Worth'::text)
(5 rows)
SELECT count(*) FROM radix_text_tbl WHERE t ^@ 'Worth';
count
-------
2
(1 row)
RESET enable_seqscan;
RESET enable_indexscan;
RESET enable_bitmapscan;

4
src/test/regress/expected/opr_sanity.out
View File

@ -718,6 +718,7 @@ sha224(bytea)
sha256(bytea)
sha384(bytea)
sha512(bytea)
starts_with(text,text)
macaddr8_eq(macaddr8,macaddr8)
macaddr8_lt(macaddr8,macaddr8)
macaddr8_le(macaddr8,macaddr8)
@ -1887,7 +1888,8 @@ ORDER BY 1, 2, 3;
4000 | 25 | <<=
4000 | 26 | >>
4000 | 27 | >>=
(121 rows)
4000 | 28 | ^@
(122 rows)
-- Check that all opclass search operators have selectivity estimators.
-- This is not absolutely required, but it seems a reasonable thing

10
src/test/regress/sql/create_index.sql
View File

@ -224,6 +224,8 @@ SELECT count(*) FROM radix_text_tbl WHERE t > 'Worth
SELECT count(*) FROM radix_text_tbl WHERE t ~>~ 'Worth St ';
SELECT count(*) FROM radix_text_tbl WHERE t ^@ 'Worth';
SELECT * FROM gpolygon_tbl ORDER BY f1 <-> '(0,0)'::point LIMIT 10;
SELECT circle_center(f1), round(radius(f1)) as radius FROM gcircle_tbl ORDER BY f1 <-> '(200,300)'::point LIMIT 10;
@ -441,6 +443,10 @@ EXPLAIN (COSTS OFF)
SELECT count(*) FROM radix_text_tbl WHERE t ~>~ 'Worth St ';
SELECT count(*) FROM radix_text_tbl WHERE t ~>~ 'Worth St ';
EXPLAIN (COSTS OFF)
SELECT count(*) FROM radix_text_tbl WHERE t ^@ 'Worth';
SELECT count(*) FROM radix_text_tbl WHERE t ^@ 'Worth';
EXPLAIN (COSTS OFF)
SELECT * FROM gpolygon_tbl ORDER BY f1 <-> '(0,0)'::point LIMIT 10;
SELECT * FROM gpolygon_tbl ORDER BY f1 <-> '(0,0)'::point LIMIT 10;
@ -578,6 +584,10 @@ EXPLAIN (COSTS OFF)
SELECT count(*) FROM radix_text_tbl WHERE t ~>~ 'Worth St ';
SELECT count(*) FROM radix_text_tbl WHERE t ~>~ 'Worth St ';
EXPLAIN (COSTS OFF)
SELECT count(*) FROM radix_text_tbl WHERE t ^@ 'Worth';
SELECT count(*) FROM radix_text_tbl WHERE t ^@ 'Worth';
RESET enable_seqscan;
RESET enable_indexscan;
RESET enable_bitmapscan;