Mailing-List: contact user-help@accumulo.apache.org; run by ezmlm
Precedence: bulk
Reply-To: user@accumulo.apache.org
Received-SPF: pass (nike.apache.org: local policy)
Content-Type: text/plain; charset=UTF-8
From: "Sukant Hajra" <qn2b6c2b9w@snkmail.com>
To: accumulo-user@incubator.apache.org
Subject: thread safety of IndexedDocIterator
Date: Mon, 05 Nov 2012 13:24:58 -0600
Message-ID: <32364-1352143501-1972@sneakemail.com>
User-Agent: Sup/git
Content-Transfer-Encoding: 8bit

We noticed that IndexedDocIterator.java has the following private static
fields:

    private static Text indexColf = DEFAULT_INDEX_COLF;
    private static Text docColf = DEFAULT_DOC_COLF;

The init method, which sets these is synchronized.  Still, though, this
synchronization doesn't seem enough to allow different runs of the iterator to
use different values for indexColf and docColf.  One run will set the "Colf"
variables one way atomically in the synchronized init method. . . and another
run and immediately interleave in alternate "Colf" settings, which breaks the
original iterator run.

For now, we're not touching the indexColf and docColf, just leaving it as the
defaults.

We're not blocked by this.  We're just curious if there's a bug in this design.
Also, if it's not a defect, we're interested in learning what system invariant
of iterator execution makes this not a problem.

Thanks,
Sukant