Last modified: 2005-01-29 04:42:35 UTC
Hello, I am using mediawiki-1.4beta5 on MySQL 3.23.58. When searching for some words, but curiously not all, I get this bug: --- A database query syntax error has occurred. This may indicate a bug in the software. The last attempted database query was: SELECT cur_id, cur_namespace, cur_title, cur_text FROM `cur`,`searchindex` WHERE cur_id=si_page AND AND cur_namespace IN (0,11) LIMIT 0,20 from within function "". MySQL returned error "1064: You have an error in your SQL syntax near 'AND cur_namespace IN (0,11) LIMIT 0,20 ' at line 1 (localhost)". --- I fixed this by changing this line in queryMain() at SearchMySQL3.php: 'WHERE cur_id=si_page AND ' . $match; to: 'WHERE cur_id=si_page ' . $match;
(In reply to comment #0) > I fixed this by changing this line in queryMain() at SearchMySQL3.php: > 'WHERE cur_id=si_page AND ' . $match; > > to: > 'WHERE cur_id=si_page ' . $match; Scratch that fix, it fixes some searches and breaks others. A proper fix needs to be devised.
Are the failures with words less than four letters or on the blacklist in FulltextStoplist.php?
(In reply to comment #2) > Are the failures with words less than four letters or on the blacklist in FulltextStoplist.php? The problem word was six letters long (the actual query was "wonder" as in Wonder of the World"). It is indeed in FulltextStoplist.php. So, these words are dropped from searches? That seems a bit much (I mean, it has words like "above" in it, what if I was searching for "Space Above and Beyond"? only "space" isn't in that wordlist). Why not just stop the search after a certain number of hits is found? Thanks for the quick response.
They are dropped from the search because the search would return *zero* results if they were included. The stop list and a (somewhat configurable) length limit is built into MySQL's full text search engine; if you search for a word on the stoplist or a too-short word no results are returned for your query. Under MySQL 3.x we combine individual searches for multiple words with a boolean 'and' condition; this means searching for "the" and "beatles" will take 0 results for "the" and 1000 results for "beatles" and combine them to return... nothing. Thus words that we know will not match are stripped out prior to search, so the results for potentially matching terms will still be shown. However there seems to be a problem with this stripping and the generated query is bogus, at least when you end up with _no_ terms to search for. Under MySQL 4.x we use MySQL's expanded built-in boolean search mode which can ignore the blacklisted terms at its end.
>They are dropped from the search because the search would return >*zero* results if they were included. The stop list and a (somewhat >configurable) length limit is built into MySQL's full text search engine; >if you search for a word on the stoplist or a too-short word no results >are returned for your query.(In reply to comment #4) > They are dropped from the search because the search would return > *zero* results if they were included. The stop list and a (somewhat > configurable) length limit is built into MySQL's full text search engine; > if you search for a word on the stoplist or a too-short word no results > are returned for your query. So you are telling me that there is no way to search for these words in MySQL? I wonder why it worked fine for that blacklisted word search when I made the change in my first post. While if I remove that word from the blacklist, I get zero results. I do not remember having had prior user complaints when using 1.3.9 either. Seems like a pretty inane MySQL feature. If I upgrade MySQL to version 4.x, will it be possible to actually search for these words and get results?
Bug now fixed in CVS, valid queries will be issued. You still won't get results though. ;) (In reply to comment #5) > So you are telling me that there is no way to search for these words in MySQL? You can if you remove them from the stop word list. (Also ignored are words appearing in over 50% of the searchable pages.) > I wonder why it worked fine for that blacklisted word search when I made the change > in my first post. That modifed query would have returned every page in the database that matched the namespace check. > While if I remove that word from the blacklist, I get zero results. The stopword list is built into MySQL. Our check is to remove known stoplist words before we run the query, so that other queried words are able to return results. If you search for a stoplisted word anyway (by removing it from MediaWiki's copy of the stoplist), then MySQL will return no results. > I do not remember having had prior user complaints when using 1.3.9 either. 1.3.9 does not contain this bug. > Seems like a pretty inane MySQL feature. If I upgrade MySQL to version 4.x, will > it be possible to actually search for these words and get results? The boolean search in MySQL 4 may or may not adhere to the stopword list in the same fashion. MediaWiki does not attempt to enforce the list on its end when set for MySQL 4 because this is not required (other words searched still return results.) If MySQL itself is still not returning results for that word, then you must modify MySQL's stopword list. See the MySQL documentation for how to do this on dev.mysql.com.
*** Bug 1357 has been marked as a duplicate of this bug. ***
