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From "Keith Turner (JIRA)" <>
Subject [jira] [Commented] (ACCUMULO-1471) doesn't respect columnFamilies
Date Thu, 30 May 2013 15:50:19 GMT


Keith Turner commented on ACCUMULO-1471:

bq.  it just being a hint that different iterators will respect to different degrees (and
generally, you might get back results that are outside the range specified)

The basic stack built by Mock and Accumulo does not treat the range and col fams as a hint.
  When iterators are independently pulled out of this system stack, the behavior may be different.

I should have outlined the history.  A long time ago Accumulo actually built the system stack
as follows.

MultiIterator(RFile(ColumnFamilySkippingIterator(LGroup())), RFile(ColumnFamilySkippingIterator(LGroup())),

With this use case, ColumnFamilySkippingIterator() would not pass column fams to data source
iterators like Rfile.LGroup(), InMemMap(), and SortedMapIter.  Also the data source iterators
used to throw an exception if column fams were passed.  Howerver this led to severe performance
problems in some cases.  ColumnFamilySkippingIterator was moved above MultiIterator and modified
to pass columns as a hint to data sources.  Data sources were modified to accept column fams,
with the understanding that filtering would always be done above.  Currently rfile is only
data source that uses this hint, in the future the in memory map will support locality groups
and use this hint also.     

The javadoc I am thinking of is specifically for SortedMapIterator, encouraging wrapping it
w/ ColumnFamilySkippingIterator if using it directly.
> doesn't respect columnFamilies
> -------------------------------------------------------
>                 Key: ACCUMULO-1471
>                 URL:
>             Project: Accumulo
>          Issue Type: Bug
>          Components: client
>    Affects Versions: 1.4.3, 1.5.0
>            Reporter: Michael Berman
>            Priority: Minor
>             Fix For: 1.5.1, 1.6.0
> If you specify columnFamilies in a seek() on a SortedMapIterator, it will happily return
results from other column families.  The arguments are never even read.

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