带通配符的SQL文本搜索

Question

I have to do a text search on 2 fields of my full-InnoDB MySql database. In the past i used:

Field1 LIKE %text% OR Field2 LIKE %text%

But now my data increased a lot and "Like" searching became too slow. So I started to search for another, better solution.

Since now I tried:

• Fulltext indices (MATCH(...) AGAINST) -> Doesn't support leading wildcards

• CONTAINS -> not avaiable in MySql (only Transact-Sql)

• Reverse fulltext indices -> work with leading wildcards but not if the match is in the middle

• REGEXP -> not really faster than LIKE

I used MyISAM "Shadow tables" for the Fulltext indices...

I don't want to use external search engines like Sphinx, Lucene or se

So my question: Is there something I forgot? I am thinking of a trick to get bothwildcards work. Like an CONTEXT Index in Oracle. Or I don't know...that's why I ask ;)

Answer 1

The leading percent '%' sign in your pattern is causing a table scan to be performed, hence the performance degradation as your data volumeincreased.

Note that this also reflects that yor data is no longe "relational" due to the non-atomic nature of he fields; that your DB is hene no longer a Relational DataBase, not withstanding that you are still using a RDBMS as the data storage engine.

The true solution is to restructure the data table by converting Field1 and Field2 back to a set of relational, meaning atomic, fields. This may be beyond any reasonable scope for the project at hand, I know; but it is the solution.