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Accumulo, mail # user - Filtering rows by presence of keys


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RE: Filtering rows by presence of keys
Bob.Thorman@... 2012-05-22, 16:46
IntersectingIterator is designed to reduce a dataset to a common column
qualifier for a collection of column families.  So I presume you mental
picture (like mine was for a long time) inverted to the logic of that
iterator.  You might try another type...like RowFilter.

-----Original Message-----
From: John Armstrong [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, May 22, 2012 11:02
To: [EMAIL PROTECTED]
Subject: Filtering rows by presence of keys

Hi, everybody.

I'm looking around to see if this sort of functionality already exists.
  I've got a table holding objects that looks like

<UUID> <Type>:<Field> <Value>

I'd like to mark objects as "active" or "inactive" by adding keys like

<UUID> ACTIVE:---- ----
<UUID> INACTIVE:---- ----

and then set up an iterator to return the previous entries if and only
if the row contains an ACTIVE column family.

I thought that at the meeting a couple weeks ago a pattern was described
to return joins using an IntersectingIterator: set up one iterator to
return the field value entries, another one to return the ACTIVE
entries, and then return only the ones I want.  But looking at
IntersectingIterator itself, this doesn't match up with my mental
picture.

So is there a known pattern matching this sort of thing? Any suggestions
on crafting one?