using includesAllPrefixes: keywords can result in duplicate results?

[Chris Muller]

Hi,

> The easiest way to make them unique is to send the distinct message. Is this
> something that always should be done?

No, it's actually something that should almost never be done until the
implementation can be changed.  They can be convenient for doing
conversions or other special-case queries, but I avoid using distinct:
true as well as OR's in my #where: clauses for ad-hoc querying.

Instead, stick to simple where: conditions as much as possible, AND'ed
conditions if you must, and then use select: blocks for OR conditions.
 To remove dups, send #asSet to the Reader.

I really need to change the OR implementation to be more "lazy", so
Magma isn't working overtime to finish queries that don't need to be
finished.  But every time I try to find time to fix this, I discover
the above solutions are almost the same and work well enough.  Someday
I will find the time and will to make using distinct: and OR's better.

> includesAllPrefixes: keywords is a sort of 'or'.

It's actually an 'and'.  The object's keywords must include 'prefix1'
AND 'prefix2', etc.  So includesAllPrefixes: will not spawn any of
those background server processes.

> Are there any other ways to make this work (since distinct is slow) ?

#asSet.  Or, use your first-class Page to enumerate (1 to:
lastKnownSize) until one page worth of unique results is accumulated;
remember the index for the start of each Page.. something like that.

 - Chris