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From DuyHai Doan <doanduy...@gmail.com>
Subject Re: Flushing after dropping a column family
Date Wed, 26 Feb 2014 16:02:52 GMT
I've played with it using a 2 nodes cluster with auto_snapshot = false in
cassandra.yaml and by deactivating durable write (no commitlog). In my
case, truncating tables allows cleaning up data.

 With "nodetool status", I can see the data payload decreasing from Gb to
some kbytes


On Wed, Feb 26, 2014 at 4:59 PM, Tupshin Harper <tupshin@tupshin.com> wrote:

> This is a known issue that is fixed in 2.1beta1.
> https://issues.apache.org/jira/browse/CASSANDRA-5202
>
> Until 2.1, we do not recommend relying on the recycling of tables through
> drop/create or truncate.
>
> However, on a single node cluster, I suspect that truncate will work far
> more reliably than drop/recreate.
>
> -Tupshin
>
>
> On Wed, Feb 26, 2014 at 10:53 AM, Ben Hood <0x6e6562@gmail.com> wrote:
>
>> On Wed, Feb 26, 2014 at 3:17 PM, DuyHai Doan <doanduyhai@gmail.com>
>> wrote:
>> > "I'm noticing that using either TRUNCATE or DROP/CREATE in cqlsh appear
>> to
>> > leave the underlying data behind."
>> >
>> >  --> What do you mean by "underlying data" ? Are you talking about
>> > "snapshots" ?
>>
>> I was referring to all of the state related to the particular column
>> family I want to set fire to, be it snapshots, parts of commit logs,
>> sstables, key caches, row caches, or anything else on or off disk that
>> relates to said column family.
>>
>> > If yes, you can wipe them using nodetool clearsnapshots command
>>
>> This is what I'm doing:
>>
>> cqlsh:bar> drop table foo;
>>
>> $ nodetool clearsnapshot bar
>> Requested clearing snapshot for: bar
>>
>> cqlsh:bar> create table foo (....);
>> cqlsh:bar> select * from foo limit 1;
>>
>> This returns nothing (as you would expect).
>>
>> But this if I re-run this again after about a minute, the data is back.
>>
>> I get the same behavior if I use nodetool cleanup, flush, compact or
>> repair.
>>
>> It's as if there is either a background app process filling the table
>> up again or if the deletion hasn't taken place.
>>
>
>

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