-Re: Finding my way through the forest of iterators
Benson Margulies 2012-02-14, 16:39
I think I'm good with the simple filtering stuff right now. I'm aiming to
make a second pass once 1.4 is released to revisit the problem of
aggregation across CQ instead of only on Value.
On Tue, Feb 14, 2012 at 11:23 AM, Keith Turner <[EMAIL PROTECTED]> wrote:
> The WholeRowIterator is one way to do this. One drawback is that it
> reads entire rows into memory.
> If rows may not fit into memory there is an efficient way to handle
> this using two iterators. One iterator creates another iterator that
> used to determine if rows contain the column, if not it seeks the
> original iterator over the row. If using the second iterator you
> determine the row contains the column, then you can read the row from
> the original iterator. This design allows you to efficiently return
> rows that meet a particular criteria w/o reading the rows into memory.
> If you are interested in learning more I can point you to examples in
> the 1.4 code.
> On Tue, Feb 14, 2012 at 9:54 AM, Benson Margulies <[EMAIL PROTECTED]>
> > I'm working with 1.3.5, and there's not a ton of javadoc in
> > org.apache.accumulo.core.iterators.
> > If I want to just filter to the rows that have a particular CF/CQ value,
> > does one of the existing iterator classes do the job, or do I need to
> > one?