Thank you for response.
I know about the option of setting TTL per column or even per item in
collection. However in my example entire row has expired, shouldn't
Cassandra be able to detect this situation and spawn a single tombstone for
entire row instead of many?
Is there any reason not doing this except that no one needs it? Is this
suitable for feature request or improvement?
Thanks.
On Wed, Jan 10, 2018 at 4:52 PM, DuyHai Doan <doanduy...@gmail.com> wrote:
> "The question is why Cassandra creates a tombstone for every column
> instead of single tombstone per row?"
>
> --> Simply because technically it is possible to set different TTL value
> on each column of a CQL row
>
> On Wed, Jan 10, 2018 at 2:59 PM, Python_Max <python....@gmail.com> wrote:
>
>> Hello, C* users and experts.
>>
>> I have (one more) question about tombstones.
>>
>> Consider the following example:
>> cqlsh> create keyspace test_ttl with replication = {'class':
>> 'SimpleStrategy', 'replication_factor': '1'}; use test_ttl;
>> cqlsh> create table items(a text, b text, c1 text, c2 text, c3 text,
>> primary key (a, b));
>> cqlsh> insert into items(a,b,c1,c2,c3) values('AAA', 'BBB', 'C111',
>> 'C222', 'C333') using ttl 60;
>> bash$ nodetool flush
>> bash$ sleep 60
>> bash$ nodetool compact test_ttl items
>> bash$ sstabledump mc-2-big-Data.db
>>
>> [
>> {
>> "partition" : {
>> "key" : [ "AAA" ],
>> "position" : 0
>> },
>> "rows" : [
>> {
>> "type" : "row",
>> "position" : 58,
>> "clustering" : [ "BBB" ],
>> "liveness_info" : { "tstamp" : "2018-01-10T13:29:25.777Z", "ttl"
>> : 60, "expires_at" : "2018-01-10T13:30:25Z", "expired" : true },
>> "cells" : [
>> { "name" : "c1", "deletion_info" : { "local_delete_time" :
>> "2018-01-10T13:29:25Z" }
>> },
>> { "name" : "c2", "deletion_info" : { "local_delete_time" :
>> "2018-01-10T13:29:25Z" }
>> },
>> { "name" : "c3", "deletion_info" : { "local_delete_time" :
>> "2018-01-10T13:29:25Z" }
>> }
>> ]
>> }
>> ]
>> }
>> ]
>>
>> The question is why Cassandra creates a tombstone for every column
>> instead of single tombstone per row?
>>
>> In production environment I have a table with ~30 columns and It gives me
>> a warning for 30k tombstones and 300 live rows. It is 30 times more then it
>> could be.
>> Can this behavior be tuned in some way?
>>
>> Thanks.
>>
>> --
>> Best regards,
>> Python_Max.
>>
>
>
--
Best regards,
Python_Max.
