From: Teodor Sigaev <teodor@sigaev.ru>
Date: Mon, 27 Jun 2016 17:41:00 +0000 (+0300)
Subject: Make exact distance match for FTS phrase operator
X-Git-Tag: REL9_6_BETA3~101
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=028350f619f7688e0453fcd2c4b25abe9ba30fa7;p=postgresql
Make exact distance match for FTS phrase operator
Phrase operator now requires exact distance betweens lexems instead of
less-or-equal.
Per discussion c19fcfec308e6ccd952cdde9e648b505@mail.gmail.com
---
diff --git a/doc/src/sgml/textsearch.sgml b/doc/src/sgml/textsearch.sgml
index 9028bedd1b..72bef9f49e 100644
--- a/doc/src/sgml/textsearch.sgml
+++ b/doc/src/sgml/textsearch.sgml
@@ -346,10 +346,10 @@ SELECT to_tsvector('error is not fatal') @@ to_tsquery('fatal <-> error');
There is a more general version of the FOLLOWED BY operator having the
form <literal><<replaceable>N</>></literal>,
- where <replaceable>N</> is an integer standing for the greatest distance
+ where <replaceable>N</> is an integer standing for the exact distance
allowed between the matching lexemes. <literal><1></literal> is
the same as <literal><-></>, while <literal><2></literal>
- allows one other lexeme to optionally appear between the matches, and so
+ allows one other lexeme to appear between the matches, and so
on. The <literal>phraseto_tsquery</> function makes use of this
operator to construct a <literal>tsquery</> that can match a multi-word
phrase when some of the words are stop words. For example:
@@ -1529,7 +1529,7 @@ SELECT to_tsquery('fat') <-> to_tsquery('cat | rat');
<para>
Returns a query that searches for a match to the first given query
followed by a match to the second given query at a distance of at
- most <replaceable>distance</replaceable> lexemes, using
+ <replaceable>distance</replaceable> lexemes, using
the <literal><<replaceable>N</>></literal>
<type>tsquery</> operator. For example:
diff --git a/src/backend/utils/adt/tsvector_op.c b/src/backend/utils/adt/tsvector_op.c
index 6117ba9b3e..04718829a0 100644
--- a/src/backend/utils/adt/tsvector_op.c
+++ b/src/backend/utils/adt/tsvector_op.c
@@ -1375,6 +1375,7 @@ TS_phrase_execute(QueryItem *curitem,
ExecPhraseData Ldata = {0, false, NULL},
Rdata = {0, false, NULL};
WordEntryPos *Lpos,
+ *LposStart,
*Rpos,
*pos_iter = NULL;
@@ -1416,52 +1417,60 @@ TS_phrase_execute(QueryItem *curitem,
pos_iter = data->pos;
}
- Lpos = Ldata.pos;
- Rpos = Rdata.pos;
-
/*
* Find matches by distance, WEP_GETPOS() is needed because
* ExecPhraseData->data can point to the tsvector's WordEntryPosVector
*/
+ Rpos = Rdata.pos;
+ LposStart = Ldata.pos;
while (Rpos < Rdata.pos + Rdata.npos)
{
+ /*
+ * We need to check all possible distances, so reset Lpos
+ * to guranteed not yet satisfied position.
+ */
+ Lpos = LposStart;
while (Lpos < Ldata.pos + Ldata.npos)
{
- if (WEP_GETPOS(*Lpos) <= WEP_GETPOS(*Rpos))
+ if (WEP_GETPOS(*Rpos) - WEP_GETPOS(*Lpos) ==
+ curitem->qoperator.distance)
{
- /*
- * Lpos is behind the Rpos, so we have to check the
- * distance condition
- */
- if (WEP_GETPOS(*Rpos) - WEP_GETPOS(*Lpos) <= curitem->qoperator.distance)
+ /* MATCH! */
+ if (data)
{
- /* MATCH! */
- if (data)
- {
- *pos_iter = WEP_GETPOS(*Rpos);
- pos_iter++;
-
- break; /* We need to build a unique result
- * array, so go to the next Rpos */
- }
- else
- {
- /*
- * We are in the root of the phrase tree and hence
- * we don't have to store the resulting positions
- */
- return true;
- }
+ /* Store position for upper phrase operator */
+ *pos_iter = WEP_GETPOS(*Rpos);
+ pos_iter++;
+
+ /*
+ * Set left start position to next, because current one
+ * could not satisfy distance for any other right
+ * position
+ */
+ LposStart = Lpos + 1;
+ break;
+ }
+ else
+ {
+ /*
+ * We are in the root of the phrase tree and hence
+ * we don't have to store the resulting positions
+ */
+ return true;
}
+
}
- else
+ else if (WEP_GETPOS(*Rpos) <= WEP_GETPOS(*Lpos) ||
+ WEP_GETPOS(*Rpos) - WEP_GETPOS(*Lpos) <
+ curitem->qoperator.distance)
{
/*
- * Go to the next Rpos, because Lpos is ahead of the
- * current Rpos
+ * Go to the next Rpos, because Lpos is ahead or on less
+ * distance than required by current operator
*/
break;
+
}
Lpos++;
diff --git a/src/test/regress/expected/tstypes.out b/src/test/regress/expected/tstypes.out
index 64d6de6050..781be70736 100644
--- a/src/test/regress/expected/tstypes.out
+++ b/src/test/regress/expected/tstypes.out
@@ -665,10 +665,10 @@ SELECT to_tsvector('simple', '1 2 3 1') @@ '1 <-> 2' AS "true";
t
(1 row)
-SELECT to_tsvector('simple', '1 2 3 1') @@ '1 <2> 2' AS "true";
- true
-------
- t
+SELECT to_tsvector('simple', '1 2 3 1') @@ '1 <2> 2' AS "false";
+ false
+-------
+ f
(1 row)
SELECT to_tsvector('simple', '1 2 3 1') @@ '1 <-> 3' AS "false";
@@ -683,6 +683,12 @@ SELECT to_tsvector('simple', '1 2 3 1') @@ '1 <2> 3' AS "true";
t
(1 row)
+SELECT to_tsvector('simple', '1 2 1 2') @@ '1 <3> 2' AS "true";
+ true
+------
+ t
+(1 row)
+
SELECT to_tsvector('simple', '1 2 11 3') @@ '1 <-> 3' AS "false";
false
-------
@@ -897,7 +903,7 @@ SELECT ts_rank_cd(' a:1 sa:2A sb:2D g'::tsvector, 'a <-> s:*');
SELECT ts_rank_cd(' a:1 sa:2A sb:2D g'::tsvector, 'a <-> s:* <-> sa:A');
ts_rank_cd
------------
- 0.0714286
+ 0
(1 row)
SELECT ts_rank_cd(' a:1 sa:2A sb:2D g'::tsvector, 'a <-> s:* <-> sa:B');
@@ -924,10 +930,10 @@ SELECT 'a:1 b:2'::tsvector @@ 'a <1> b'::tsquery AS "true";
t
(1 row)
-SELECT 'a:1 b:2'::tsvector @@ 'a <2> b'::tsquery AS "true";
- true
-------
- t
+SELECT 'a:1 b:2'::tsvector @@ 'a <2> b'::tsquery AS "false";
+ false
+-------
+ f
(1 row)
SELECT 'a:1 b:3'::tsvector @@ 'a <-> b'::tsquery AS "false";
@@ -954,10 +960,10 @@ SELECT 'a:1 b:3'::tsvector @@ 'a <2> b'::tsquery AS "true";
t
(1 row)
-SELECT 'a:1 b:3'::tsvector @@ 'a <3> b'::tsquery AS "true";
- true
-------
- t
+SELECT 'a:1 b:3'::tsvector @@ 'a <3> b'::tsquery AS "false";
+ false
+-------
+ f
(1 row)
-- tsvector editing operations
diff --git a/src/test/regress/sql/tstypes.sql b/src/test/regress/sql/tstypes.sql
index 738ec824b9..abcf1504ce 100644
--- a/src/test/regress/sql/tstypes.sql
+++ b/src/test/regress/sql/tstypes.sql
@@ -130,9 +130,10 @@ SELECT 'supeznova supernova'::tsvector @@ 'super:*'::tsquery AS "true";
--phrase search
SELECT to_tsvector('simple', '1 2 3 1') @@ '1 <-> 2' AS "true";
-SELECT to_tsvector('simple', '1 2 3 1') @@ '1 <2> 2' AS "true";
+SELECT to_tsvector('simple', '1 2 3 1') @@ '1 <2> 2' AS "false";
SELECT to_tsvector('simple', '1 2 3 1') @@ '1 <-> 3' AS "false";
SELECT to_tsvector('simple', '1 2 3 1') @@ '1 <2> 3' AS "true";
+SELECT to_tsvector('simple', '1 2 1 2') @@ '1 <3> 2' AS "true";
SELECT to_tsvector('simple', '1 2 11 3') @@ '1 <-> 3' AS "false";
SELECT to_tsvector('simple', '1 2 11 3') @@ '1:* <-> 3' AS "true";
@@ -180,12 +181,12 @@ SELECT ts_rank_cd(' a:1 sa:2A sb:2D g'::tsvector, 'a <-> s:* <-> sa:B');
SELECT 'a:1 b:2'::tsvector @@ 'a <-> b'::tsquery AS "true";
SELECT 'a:1 b:2'::tsvector @@ 'a <0> b'::tsquery AS "false";
SELECT 'a:1 b:2'::tsvector @@ 'a <1> b'::tsquery AS "true";
-SELECT 'a:1 b:2'::tsvector @@ 'a <2> b'::tsquery AS "true";
+SELECT 'a:1 b:2'::tsvector @@ 'a <2> b'::tsquery AS "false";
SELECT 'a:1 b:3'::tsvector @@ 'a <-> b'::tsquery AS "false";
SELECT 'a:1 b:3'::tsvector @@ 'a <0> b'::tsquery AS "false";
SELECT 'a:1 b:3'::tsvector @@ 'a <1> b'::tsquery AS "false";
SELECT 'a:1 b:3'::tsvector @@ 'a <2> b'::tsquery AS "true";
-SELECT 'a:1 b:3'::tsvector @@ 'a <3> b'::tsquery AS "true";
+SELECT 'a:1 b:3'::tsvector @@ 'a <3> b'::tsquery AS "false";
-- tsvector editing operations