>Description:
It appears that MySQL can have trouble with a searchterm
in a boolean-mode fulltext index search which is both prefixed
with + and suffixed with *, when that searchterm is paired
with another required term. The empty set is returned when there are rows
which should match.
>How-To-Repeat:
I have not been able to duplicate this bug in a test case, but it
is clearly occurring in my actual table, as the following demonstrates:
mysql> SELECT article_id as id, title FROM search WHERE
MATCH(title) AGAINST ('+Anabaptists +Reist' IN BOOLEAN MODE);
+------+-------------------------------------------------+
| id | title |
+------+-------------------------------------------------+
| 2538 | Hans Reist House and the "Vale of Anabaptists." |
+------+-------------------------------------------------+
1 row in set (0.01 sec)
mysql> SELECT article_id as id, title FROM search WHERE
MATCH(title) AGAINST ('+Anabapt* +Reist' IN BOOLEAN MODE);
Empty set (0.01 sec)
But this is odd - if I replace Reist
with Hans, I now get a different row entirely:
mysql> SELECT article_id as id, title FROM search WHERE
MATCH(title) AGAINST ('+Anabapt* +Hans' IN BOOLEAN MODE);
+-----+--------------------------------------------------------------------+
| id | title |
+-----+--------------------------------------------------------------------+
| 462 | Hans Landis of Zurich (d. 1614): the last Swiss Anabaptist martyr. |
+-----+--------------------------------------------------------------------+
1 row in set (0.01 sec)
The only possible key that I've come up with is that "Anabaptist" or
"Anabaptists" is a fairly common word in this field - appears in 296 out
of 3249 rows - but not nearly half or anything like that.
Unfortunately, I have not been able to find another word that causes
this bug.
If it matters, I have dropped and recreated the table several times. I
have tried creating the fulltext index both before and after inserting the
data.
>Fix:
As I haven't been able to isolate the exact nature of the bug, I
don't know of a fix or workaround.
>Submitter-Id: <submitter ID>
>Originator: Carl J Meyer
>Organization:
Mennonite.net
>MySQL support: none
>Synopsis: boolean-mode fulltext search: problems with +searchterm*
>Severity: serious
>Priority: medium
>Category: mysql
>Class: sw-bug
>Release: mysql-4.0.1-alpha (Official MySQL RPM)
>Environment:
System: Linux mennonet1 2.4.17 #2 SMP Tue Jan 29 12:37:22 EST 2002 i686 unknown
Architecture: i686
Some paths: /usr/bin/perl /usr/bin/make /usr/bin/gmake /usr/bin/gcc /usr/bin/cc
GCC: Reading specs from /usr/lib/gcc-lib/i386-redhat-linux/2.96/specs
gcc version 2.96 20000731 (Red Hat Linux 7.1 2.96-98)
Compilation info: CC='gcc' CFLAGS='-O6 -fno-omit-frame-pointer -mpentium' CXX='gcc'
CXXFLAGS='-O6 -fno-omit-frame-pointer -felide-constructors
-fno-exceptions -fno-rtti -mpentium' LDFLAGS=''
LIBC:
lrwxrwxrwx 1 root root 13 Apr 10 17:12 /lib/libc.so.6 -> libc-2.2.4.so
-rwxr-xr-x 2 root root 1285788 Apr 2 11:58 /lib/libc-2.2.4.so
-rw-r--r-- 1 root root 27332668 Apr 2 11:42 /usr/lib/libc.a
-rw-r--r-- 1 root root 178 Apr 2 11:42 /usr/lib/libc.so
Configure command: ./configure --disable-shared --with-mysqld-ldflags=-all-static
--with-client-ldflags=-all-static --without-berkeley-db --with-innodb
--enable-assembler --with-mysqld-user=mysql
--with-unix-socket-path=/var/lib/mysql/mysql.sock --prefix=/
--with-extra-charsets=complex --exec-prefix=/usr --libexecdir=/usr/sbin
--sysconfdir=/etc --datadir=/usr/share --localstatedir=/var/lib/mysql
--infodir=/usr/info --includedir=/usr/include --mandir=/usr/man --with-embedded-server
--enable-thread-safe-client '--with-comment=Official MySQL RPM'
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