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Accumulo, mail # user - upgrade from 1.3 to 1.4


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Re: upgrade from 1.3 to 1.4
Aaron Cordova 2012-01-03, 17:51
yeah in this case i suppose there's not much that can go wrong. even if both combiners are turned off at some point, when the summingcombiner is turned on it should do the right thing. As long as the values that get written don't get transformed differently, i.e. as long as the functionality is really identical.

On Jan 3, 2012, at 12:45 PM, Adam Fuchs wrote:

> Oh yeah, and they're (mutually) idempotent too, right?
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> Adam
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> On Tue, Jan 3, 2012 at 12:43 PM, Adam Fuchs <[EMAIL PROTECTED]> wrote:
> Why not add the combiner (so that both are enabled) and then remove the aggregator? The two iterators should be commutative and associative, so results should be reasonable and compactions should be safe when both are enabled in the tree.
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> Adam
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> On Tue, Jan 3, 2012 at 12:39 PM, Billie J Rinaldi <[EMAIL PROTECTED]> wrote:
> On Tuesday, January 3, 2012 11:51:19 AM, "Aaron Cordova" <[EMAIL PROTECTED]> wrote:
> > Is it ok to disable the stringsummation aggregator and then enable the
> > summingcombiner through the shell? Should I take the table offline
> > first?
>
> If the table is quiet (i.e. not compacting), then it shouldn't be a problem to do the switch while it's online.  Queries might get unexpected results during the switch.  If you've removed the VersioningIterator from the table, then you could even make the change during compactions.  However, if there is versioning, there would be the possibility of it removing versions instead of aggregating during compactions.
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> Billie
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