List:Falcon Storage Engine« Previous MessageNext Message »
From:Ann W. Harrison Date:October 22 2008 4:40pm
Subject:Non-indexed selections
View as plain text  
Lars-Eric,

    You asked on IRC about non-indexed selection criteria.  For our
first release, we don't handle them at all.  We return all rows and
the server does the filtering.  The server is capable of passing
non-indexed conditions to the engines - NDB for one uses that - but
it really doesn't save very much for an in-process engine.  At
some point, the work that Timour is doing may let the server pass
multiple indexed conditions to the server (e.g.

    select order_amount from orders
      where customer_id = 25 and order_date = '22 Oct 2008'

when both order_date and customer_id are indexed).  When that
is possible, Falcon can use logically combine the bitmaps for
the two indexes and retrieve only rows where both conditions
are satisfied.

    But for now, all we do is lookups on a single index or return
the whole table.


Cheers,


Ann
Thread
Non-indexed selectionsAnn W. Harrison22 Oct
  • Re: Non-indexed selectionsLars-Erik Bjørk22 Oct
    • Re: Non-indexed selectionsAnn W. Harrison22 Oct
      • Re: Non-indexed selectionsLars-Erik Bjørk23 Oct