Re: Indexing a CLOB

From: Jaromir D.B. Nemec <>
Date: Thu, 12 Feb 2009 22:34:48 +0100
Message-ID: <F6DBB3AA82E149608203034E7263E777_at_ADLA>

> The only problem then was that domain indexes couldn't be partitioned. With 9i and 10g I believe that restriction was removed, which makes Oracle Text indexes and the tables
> they're on partitionable.

I'd better say the partitioning of the Text index is simulated, by creating a separate index for each partition. This is of course transparent in maintenance. Only one local index is created. The only consequence is in kind of "unbalanced" user_tables. For each partition of an indexed table some 4-5 (not sure exactly) tables hosting the text index are created.    

In my experience a crucial point in text indexing is the correct definition of print and stop characters. For example customer_id can be treated as single token or as two tokens customer and id depending on the definition of the underscore. This has a consequence in search.

If there is a user interface to pass in the search string it is meaningful to define some filter on the search strings to handle reserved words. For example a search for "near real time" leads to ORA- exception as "near" is a search function. A good example is Ask Tom where the above search string is transformed to {near} and {real} and {time} which returs that what most people probably expect.  

HTH   Jaromir D.B. Nemec

Received on Thu Feb 12 2009 - 15:34:48 CST

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