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From Luiz Carlos Jr <l...@s1mbi0se.com.br>
Subject Re: Unexpected value after insert
Date Tue, 05 Nov 2013 22:28:18 GMT
Hi Christopher,

Actually it's not a counter, but just a field that stores integers. I'm
logging the expected values but not the command itself because I'm using
pycassa to send it. I'm absolutely sure that it's not an overflow case. I'm
talking about numbers in order of 10~100k with no math operators that could
raise an expection (only one subtraction operation).

Any other ideas ? Thanks for the tips !


On Tue, Nov 5, 2013 at 12:29 PM, Christopher Smith <cbsmith@gmail.com>wrote:

> Given your use case I'd recommend not using a counter for the field.
>
> Are you logging the update command you are sending Cassandra? Are you sure
> you aren't overflowing the value either in Cassandra or in your batch code?
>
> On Monday, November 4, 2013, Luiz Carlos Jr wrote:
>
> > Hi !
> >
> > I have a script written in python that should update a counter in
> > Cassandra. It acts like a batch that corrects the counter.
> >
> > What script does is: get the real value that should be at database, get
> the
> > current value that is persisted at database, calculates the difference
> > between values and finally send insert command to specific row key
> passing
> > the diff to update the counter.
> >
> > All works fine. I got the correct values and diffs but, after insert
> > command, the value of row key is not the expected.
> >
> > Example:
> > Real Value = 35000
> > Current DB Value = 30000
> > Diff Value = 5000
> >
> > I sent the insert command passing diff=5000 so, the expected new DB value
> > should be 35000. But sometimes the new DB value is a crazy negative
> number,
> > like -360.000. It doesn't make any sense, because there's no combination
> of
> > values and operators that could result on a value like that.
> >
> > And, if i run the script again, the final persisted value is correct. If
> I
> > try again later the final persisted value appears wrong again...
> >
> > Can anyone help me with this ? The same script sometimes works fine and
> > sometimes persists a crazy value.
> >
> > Thank you !
> >
>
>
> --
> Chris
>

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