Hi Carl,
Developers have told me that leading wildcards are way more costly than trailing ones.
Those are indeed the baseline constraints of traditional database indexes.
If there's good news, we've built a so-called "trigram"-based search index on top of that, which supports both leading and trailing wildcards efficiently.
However, this capability is perhaps not yet exposed to the query language in an ideal way.
Currently, unquoted terms implicitly behave as though they had both leading and trailing wildcards. Thus a search for 'vert' (without quotes) would find metadata like 'vertical' as well as 'advertisement'. Whereas surrounding the term in double-quotes, "vert", would find only an exact match.
We've discussed internally how this default behavior could produce unexpected results, and so this has been on our list to improve.
But: since the underlying support for wildcards is already there in the index, it should be possible to move toward more explicit support for wildcards in the query language (e.g. vert, *vert, vert*, *vert*) rather than having wildcarding occur by default.
Regards,
Bill