Default Lucene index for String cache values

[Ilya Korol]

Hi, All.

According to https://issues.apache.org/jira/browse/IGNITE-14805 there is 
default index creation for caches with String values:


if (type().valueClass() == String.class) {
    try {
        luceneIdx = new GridLuceneIndex(idx.kernalContext(), 
tbl.cacheName(), type);
    }
    catch (IgniteCheckedException e1) {
        throw new IgniteException(e1);
    }
}


Does this really necessary?  What about disabling this feature by 
default and enabling it only by demand (to reduce unnecessary 
performance hit even if its not very huge)? I guess additional option 
could be introduced to do so.

Any ideas?