Ensure that a tsquery like '!foo' matches empty tsvectors.

!foo means "the tsvector does not contain foo", and therefore it should
match an empty tsvector.  ts_match_vq() overenthusiastically supposed
that an empty tsvector could never match any query, so it forcibly
returned FALSE, the wrong answer.  Remove the premature optimization.

Our behavior on this point was inconsistent, because while seqscans and
GIST index searches both failed to match empty tsvectors, GIN index
searches would find them, since GIN scans don't rely on ts_match_vq().
That makes this certainly a bug, not a debatable definition disagreement,
so back-patch to all supported branches.

Report and diagnosis by Tom Dunstan (bug #14515); added test cases by me.

Discussion: https://postgr.es/m/20170126025524[email protected]

diff --git a/src/backend/utils/adt/tsvector_op.c b/src/backend/utils/adt/tsvector_op.c
index eb15937b3559aff591119f2d8b205fd8263bd0db..4289bef5da7133435bacc90b342c558b4b245117 100644 (file)
--- a/src/backend/utils/adt/tsvector_op.c
+++ b/src/backend/utils/adt/tsvector_op.c
@@ -784,7 +784,8 @@ ts_match_vq(PG_FUNCTION_ARGS)
        CHKVAL          chkval;
        bool            result;
 
-       if (!val->size || !query->size)
+       /* empty query matches nothing */
+       if (!query->size)
        {
                PG_FREE_IF_COPY(val, 0);
                PG_FREE_IF_COPY(query, 1);

diff --git a/src/test/regress/expected/tsearch.out b/src/test/regress/expected/tsearch.out
index 59e2a06d0e6f94642a6a94f8bc3db2124b003663..909212e1a76cd95a8d6f214eebce6773045c22f9 100644 (file)
--- a/src/test/regress/expected/tsearch.out
+++ b/src/test/regress/expected/tsearch.out
@@ -98,8 +98,108 @@ SELECT count(*) FROM test_tsvector WHERE a @@ 'w:*|q:*';
    494
 (1 row)
 
+SELECT count(*) FROM test_tsvector WHERE a @@ any ('{wr,qh}');
+ count 
+-------
+   158
+(1 row)
+
+SELECT count(*) FROM test_tsvector WHERE a @@ 'no_such_lexeme';
+ count 
+-------
+     0
+(1 row)
+
+SELECT count(*) FROM test_tsvector WHERE a @@ '!no_such_lexeme';
+ count 
+-------
+   508
+(1 row)
+
 create index wowidx on test_tsvector using gist (a);
 SET enable_seqscan=OFF;
+SET enable_indexscan=ON;
+SET enable_bitmapscan=OFF;
+explain (costs off) SELECT count(*) FROM test_tsvector WHERE a @@ 'wr|qh';
+                      QUERY PLAN                       
+-------------------------------------------------------
+ Aggregate
+   ->  Index Scan using wowidx on test_tsvector
+         Index Cond: (a @@ '''wr'' | ''qh'''::tsquery)
+(3 rows)
+
+SELECT count(*) FROM test_tsvector WHERE a @@ 'wr|qh';
+ count 
+-------
+   158
+(1 row)
+
+SELECT count(*) FROM test_tsvector WHERE a @@ 'wr&qh';
+ count 
+-------
+    17
+(1 row)
+
+SELECT count(*) FROM test_tsvector WHERE a @@ 'eq&yt';
+ count 
+-------
+     6
+(1 row)
+
+SELECT count(*) FROM test_tsvector WHERE a @@ 'eq|yt';
+ count 
+-------
+    98
+(1 row)
+
+SELECT count(*) FROM test_tsvector WHERE a @@ '(eq&yt)|(wr&qh)';
+ count 
+-------
+    23
+(1 row)
+
+SELECT count(*) FROM test_tsvector WHERE a @@ '(eq|yt)&(wr|qh)';
+ count 
+-------
+    39
+(1 row)
+
+SELECT count(*) FROM test_tsvector WHERE a @@ 'w:*|q:*';
+ count 
+-------
+   494
+(1 row)
+
+SELECT count(*) FROM test_tsvector WHERE a @@ any ('{wr,qh}');
+ count 
+-------
+   158
+(1 row)
+
+SELECT count(*) FROM test_tsvector WHERE a @@ 'no_such_lexeme';
+ count 
+-------
+     0
+(1 row)
+
+SELECT count(*) FROM test_tsvector WHERE a @@ '!no_such_lexeme';
+ count 
+-------
+   508
+(1 row)
+
+SET enable_indexscan=OFF;
+SET enable_bitmapscan=ON;
+explain (costs off) SELECT count(*) FROM test_tsvector WHERE a @@ 'wr|qh';
+                         QUERY PLAN                          
+-------------------------------------------------------------
+ Aggregate
+   ->  Bitmap Heap Scan on test_tsvector
+         Recheck Cond: (a @@ '''wr'' | ''qh'''::tsquery)
+         ->  Bitmap Index Scan on wowidx
+               Index Cond: (a @@ '''wr'' | ''qh'''::tsquery)
+(5 rows)
+
 SELECT count(*) FROM test_tsvector WHERE a @@ 'wr|qh';
  count 
 -------
@@ -148,10 +248,35 @@ SELECT count(*) FROM test_tsvector WHERE a @@ any ('{wr,qh}');
    158
 (1 row)
 
+SELECT count(*) FROM test_tsvector WHERE a @@ 'no_such_lexeme';
+ count 
+-------
+     0
+(1 row)
+
+SELECT count(*) FROM test_tsvector WHERE a @@ '!no_such_lexeme';
+ count 
+-------
+   508
+(1 row)
+
 RESET enable_seqscan;
+RESET enable_indexscan;
+RESET enable_bitmapscan;
 DROP INDEX wowidx;
 CREATE INDEX wowidx ON test_tsvector USING gin (a);
 SET enable_seqscan=OFF;
+-- GIN only supports bitmapscan, so no need to test plain indexscan
+explain (costs off) SELECT count(*) FROM test_tsvector WHERE a @@ 'wr|qh';
+                         QUERY PLAN                          
+-------------------------------------------------------------
+ Aggregate
+   ->  Bitmap Heap Scan on test_tsvector
+         Recheck Cond: (a @@ '''wr'' | ''qh'''::tsquery)
+         ->  Bitmap Index Scan on wowidx
+               Index Cond: (a @@ '''wr'' | ''qh'''::tsquery)
+(5 rows)
+
 SELECT count(*) FROM test_tsvector WHERE a @@ 'wr|qh';
  count 
 -------
@@ -200,6 +325,18 @@ SELECT count(*) FROM test_tsvector WHERE a @@ any ('{wr,qh}');
    158
 (1 row)
 
+SELECT count(*) FROM test_tsvector WHERE a @@ 'no_such_lexeme';
+ count 
+-------
+     0
+(1 row)
+
+SELECT count(*) FROM test_tsvector WHERE a @@ '!no_such_lexeme';
+ count 
+-------
+   508
+(1 row)
+
 RESET enable_seqscan;
 INSERT INTO test_tsvector VALUES ('???', 'DFG:1A,2B,6C,10 FGH');
 SELECT * FROM ts_stat('SELECT a FROM test_tsvector') ORDER BY ndoc DESC, nentry DESC, word LIMIT 10;

diff --git a/src/test/regress/expected/tstypes.out b/src/test/regress/expected/tstypes.out
index 6284fb6181340dd806089384c8d74e9392869132..da4c760175bac00ac544a0e3fd3eb56a226dadf1 100644 (file)
--- a/src/test/regress/expected/tstypes.out
+++ b/src/test/regress/expected/tstypes.out
@@ -625,3 +625,15 @@ SELECT ts_rank_cd(' a:1 s:2 d g'::tsvector, 'a & s');
         0.1
 (1 row)
 
+select to_tsvector('simple', 'x y q y') @@ '!foo' AS "true";
+ true 
+------
+ t
+(1 row)
+
+select to_tsvector('simple', '') @@ '!foo' AS "true";
+ true 
+------
+ t
+(1 row)
+

diff --git a/src/test/regress/sql/tsearch.sql b/src/test/regress/sql/tsearch.sql
index 1ba2cdb3829b029be6a424eae5c156124a466dc1..355fbe16368f2910867e51e7721bb9e9c3fc4532 100644 (file)
--- a/src/test/regress/sql/tsearch.sql
+++ b/src/test/regress/sql/tsearch.sql
@@ -48,10 +48,17 @@ SELECT count(*) FROM test_tsvector WHERE a @@ 'eq|yt';
 SELECT count(*) FROM test_tsvector WHERE a @@ '(eq&yt)|(wr&qh)';
 SELECT count(*) FROM test_tsvector WHERE a @@ '(eq|yt)&(wr|qh)';
 SELECT count(*) FROM test_tsvector WHERE a @@ 'w:*|q:*';
+SELECT count(*) FROM test_tsvector WHERE a @@ any ('{wr,qh}');
+SELECT count(*) FROM test_tsvector WHERE a @@ 'no_such_lexeme';
+SELECT count(*) FROM test_tsvector WHERE a @@ '!no_such_lexeme';
 
 create index wowidx on test_tsvector using gist (a);
 
 SET enable_seqscan=OFF;
+SET enable_indexscan=ON;
+SET enable_bitmapscan=OFF;
+
+explain (costs off) SELECT count(*) FROM test_tsvector WHERE a @@ 'wr|qh';
 
 SELECT count(*) FROM test_tsvector WHERE a @@ 'wr|qh';
 SELECT count(*) FROM test_tsvector WHERE a @@ 'wr&qh';
@@ -61,14 +68,37 @@ SELECT count(*) FROM test_tsvector WHERE a @@ '(eq&yt)|(wr&qh)';
 SELECT count(*) FROM test_tsvector WHERE a @@ '(eq|yt)&(wr|qh)';
 SELECT count(*) FROM test_tsvector WHERE a @@ 'w:*|q:*';
 SELECT count(*) FROM test_tsvector WHERE a @@ any ('{wr,qh}');
+SELECT count(*) FROM test_tsvector WHERE a @@ 'no_such_lexeme';
+SELECT count(*) FROM test_tsvector WHERE a @@ '!no_such_lexeme';
+
+SET enable_indexscan=OFF;
+SET enable_bitmapscan=ON;
+
+explain (costs off) SELECT count(*) FROM test_tsvector WHERE a @@ 'wr|qh';
+
+SELECT count(*) FROM test_tsvector WHERE a @@ 'wr|qh';
+SELECT count(*) FROM test_tsvector WHERE a @@ 'wr&qh';
+SELECT count(*) FROM test_tsvector WHERE a @@ 'eq&yt';
+SELECT count(*) FROM test_tsvector WHERE a @@ 'eq|yt';
+SELECT count(*) FROM test_tsvector WHERE a @@ '(eq&yt)|(wr&qh)';
+SELECT count(*) FROM test_tsvector WHERE a @@ '(eq|yt)&(wr|qh)';
+SELECT count(*) FROM test_tsvector WHERE a @@ 'w:*|q:*';
+SELECT count(*) FROM test_tsvector WHERE a @@ any ('{wr,qh}');
+SELECT count(*) FROM test_tsvector WHERE a @@ 'no_such_lexeme';
+SELECT count(*) FROM test_tsvector WHERE a @@ '!no_such_lexeme';
 
 RESET enable_seqscan;
+RESET enable_indexscan;
+RESET enable_bitmapscan;
 
 DROP INDEX wowidx;
 
 CREATE INDEX wowidx ON test_tsvector USING gin (a);
 
 SET enable_seqscan=OFF;
+-- GIN only supports bitmapscan, so no need to test plain indexscan
+
+explain (costs off) SELECT count(*) FROM test_tsvector WHERE a @@ 'wr|qh';
 
 SELECT count(*) FROM test_tsvector WHERE a @@ 'wr|qh';
 SELECT count(*) FROM test_tsvector WHERE a @@ 'wr&qh';
@@ -78,8 +108,11 @@ SELECT count(*) FROM test_tsvector WHERE a @@ '(eq&yt)|(wr&qh)';
 SELECT count(*) FROM test_tsvector WHERE a @@ '(eq|yt)&(wr|qh)';
 SELECT count(*) FROM test_tsvector WHERE a @@ 'w:*|q:*';
 SELECT count(*) FROM test_tsvector WHERE a @@ any ('{wr,qh}');
+SELECT count(*) FROM test_tsvector WHERE a @@ 'no_such_lexeme';
+SELECT count(*) FROM test_tsvector WHERE a @@ '!no_such_lexeme';
 
 RESET enable_seqscan;
+
 INSERT INTO test_tsvector VALUES ('???', 'DFG:1A,2B,6C,10 FGH');
 SELECT * FROM ts_stat('SELECT a FROM test_tsvector') ORDER BY ndoc DESC, nentry DESC, word LIMIT 10;
 SELECT * FROM ts_stat('SELECT a FROM test_tsvector', 'AB') ORDER BY ndoc DESC, nentry DESC, word;

diff --git a/src/test/regress/sql/tstypes.sql b/src/test/regress/sql/tstypes.sql
index fd7c7024f5e547018323b1766eb229afb8c541d9..6bc47c007f70a502968c7a4576bb4dd392549144 100644 (file)
--- a/src/test/regress/sql/tstypes.sql
+++ b/src/test/regress/sql/tstypes.sql
@@ -115,3 +115,6 @@ SELECT ts_rank_cd(' a:1 s:2 d g'::tsvector, 'a | s');
 SELECT ts_rank_cd(' a:1 s:2C d g'::tsvector, 'a & s');
 SELECT ts_rank_cd(' a:1 s:2B d g'::tsvector, 'a & s');
 SELECT ts_rank_cd(' a:1 s:2 d g'::tsvector, 'a & s');
+
+select to_tsvector('simple', 'x y q y') @@ '!foo' AS "true";
+select to_tsvector('simple', '') @@ '!foo' AS "true";