[Exist-open] Question about range indexes and special characters

[Rico H. <ri...@gm...>]

Hello,

I have a question about using a range index on a string that contains
special characters.

I have an index on all elements with the name "siteId":

    <create qname="siteId" type="xs:string" />

These siteIds contain alphanumeric strings, separated by a token. In fact, a
siteId represents a location in a tree and is described by its root path.
For the separator token, I have chosen an exclamation mark (after many other
considerations). So for example, I have the following siteIds:

    ww!site1!
    ww!site1!sub!
    ww!site2!
    ...etc...

All of my queries on siteId involve checking equality with '=' or prefix
checking with starts-with().

With logging set to debug, my log gets spammed with a lot of these lines:

    [org.exist.storage.NativeValueIndex]  - Match will begin index scan at
'ww'

A quick glance at the source code shows that it makes exceptions for
non-alphanumeric characters, but I'm not entirely sure what that is.

So my question is basically this: is my use of the ! as a separator
influencing the efficiency of the index? Many of my queries are not
performing as well as I'd hope and this is one of my suspects...

Thanks for any help.

Regards,
Rico