Send a delete with a higher time stamp, reduce the gc_grace_seconds on the CF, get the CF to compact (manually or automatically) and then return the gc_grace_seconds. 

See the steps I took here to resolve a similar problem http://thelastpickle.com/2011/12/15/Anatomy-of-a-Cassandra-Partition/

Hope that helps. 
-----------------
Aaron Morton
Freelance Developer
@aaronmorton

On 1/02/2012, at 12:07 PM, Hiren Shah wrote:

Hi,
 
I was mystified when I was not able to update a column ccc for a few keys in my test_cf, but was able to update that for all other keys. Then, I noticed that the column for that key is set to be deleted in future (year 6172 !) –
 
DEBUG [ReadStage:1191] 2012-01-31 22:21:48,374 SliceQueryFilter.java (line 123) collecting 0 of 1000000: ccc:true:4@1326231110794000
 
The timestamp must be from buggy code putting extra zeros, or from some issue in upgrade from 0.8.7 to 1.0.6 to 1.0.7. It almost seems like Cassandra ‘sees’ a few extra zeroes appended to the timestamp. The value without the three zeroes falls at the right time for the row inserted above and the time of delete below.
 
Recent records fetch ok –
DEBUG [ReadStage:1278] 2012-01-31 23:00:35,145 SliceQueryFilter.java (line 123) collecting 0 of 100: ccc:false:303@1328024823949!31536000
 
More important at this point  is to clean this up.
 
I tried to overwrite a value for that through CLI and it worked, sort of –
 
DEBUG [ReadStage:1099] 2012-01-31 21:15:34,385 SliceQueryFilter.java (line 123) collecting 0 of 100: ccc:false:1@1328043222690000
 
But the timestamp still keeps the extra zeroes. I cannot set it programmatically because my code uses current timestamp.
 
I tried to delete the whole record from CLI. The record cannot be queried anymore, but I still see the column (and others for the record) in the log. I did repair, cleanup and compact, but still no luck.
 
How can I delete a future dated column? Or overwrite it (without using a timestamp in year 7000!) ?
 
I am using cassandra 1.0.7.
 

Hiren Shah | R&D Team

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