There are two primary types of text query that can be performed by Texis. The first form is used to find those records which match the query, and is used when you only care if the record does or does not match. The second form is used when you want to rank the results and produce the best answers first.
The first type of query is done with
LIKE3 to avoid post processing
if the index can not fully resolve the query. The ranking queries are done
LIKER is a faster, and less precise ranking figure
than the one returned by
LIKEP. The ranking takes into account how many of
the query terms are present, as well as their weight, and for
close together the words are, and where in the document they occur. Most
queries will use
LIKER used in special
circumstances when you want to avoid the post-processing that would fully
resolve the query.
There are also two forms of Metamorph index, the Metamorph inverted index
and the Metamorph index. The inverted form contains additional information
which allows phrases to be resolved and
LIKEP rankings to be calculated
entirely using the index. This improved functionality comes at a cost in
terms of space.
If your queries are single word
LIKE queries then the Metamorph
index has all the information needed, so the additional overhead of
the inverted index is not needed.