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From aaron morton <aa...@thelastpickle.com>
Subject Re: Delete doesn't remove row key?
Date Wed, 01 Feb 2012 07:59:19 GMT
> Second, a followup question: So the row keys will be deleted after 1) the GC grace period
expires, and 2) I do a compaction?
Automatic compaction will purge the tombstones. 

> Third: Assuming the answer is yes, is there any way to manually force GC of the deleted
keys without doing the full "GC shuffle" (setting the GC grace period artificially low, restarting,
compacting, setting grace period back to normal, restarting)?
No. But you do not need to restart. gc_grace_seconds is set per CF and can be updated without
a restart. 

Cheers

-----------------
Aaron Morton
Freelance Developer
@aaronmorton
http://www.thelastpickle.com

On 1/02/2012, at 2:32 PM, Todd Fast wrote:

> First, thanks! I'd read that before, but didn't associate doing a range scan with using
the CLI, much less doing "select count(*)" in CQL. Now I know what to call the phenomenon.
> 
> Second, a followup question: So the row keys will be deleted after 1) the GC grace period
expires, and 2) I do a compaction?
> 
> Third: Assuming the answer is yes, is there any way to manually force GC of the deleted
keys without doing the full "GC shuffle" (setting the GC grace period artificially low, restarting,
compacting, setting grace period back to normal, restarting)?
> 
> Todd
> 
> On 1/31/2012 5:03 PM, Benjamin Hawkes-Lewis wrote:
>> On Wed, Feb 1, 2012 at 12:58 AM, Todd Fast<todd@conga.com>  wrote:
>>> I added a row with a single column to my 1.0.8 single-node cluster:
>>> 
>>>    RowKey: aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa
>>>    =>  (column=test, value=hi, timestamp=...)
>>> 
>>> I immediately deleted the row using both the CLI and CQL:
>>> 
>>>    del Foo[lexicaluuid('aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa')];
>>>    delete from Foo using consistency all where
>>> KEY=aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa
>>> 
>>> In either case, the column "test" is gone but the empty row key still
>>> remains, and the row count reflects the presence of this phantom row.
>>> 
>>> I've tried nodetool compact/repair/flush/cleanup/scrub/etc. and nothing
>>> removes the row key.
>> http://wiki.apache.org/cassandra/FAQ#range_ghosts
>> 
>> --
>> Benjamin Hawkes-Lewis


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