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Posted to user@cassandra.apache.org by cem <ca...@gmail.com> on 2012/03/11 11:36:45 UTC
TTL 3 hours + GC grace 0
Hi All,
I am using TTL 3 hours and GC grace 0 for a CF. I have a normal CF that has
records with TTL 3 hours and I dont send any delete request. I just wonder
if using GC grace 0 will cause any problem except extra Memory/IO/network
load. I know that gc grace is for not transferring deleted records after a
down node comes back. So I assumed that transferring expired records will
not cause any problem.
Do you have any idea? Thank you!
Regards,
Cem.
Re: TTL 3 hours + GC grace 0
Posted by cem <ca...@gmail.com>.
Thank you for the swift response.
Cem.
On Sun, Mar 11, 2012 at 11:03 PM, Peter Schuller <
peter.schuller@infidyne.com> wrote:
> > I am using TTL 3 hours and GC grace 0 for a CF. I have a normal CF that
> has
> > records with TTL 3 hours and I dont send any delete request. I just
> wonder
> > if using GC grace 0 will cause any problem except extra Memory/IO/network
> > load. I know that gc grace is for not transferring deleted records after
> a
> > down node comes back. So I assumed that transferring expired records
> will
> > not cause any problem.
> >
> > Do you have any idea? Thank you!
>
> If you do not perform any deletes at all, a GC grace of 0 should be
> fine. But if you don't, the GC grace should not really be relevant
> either. So I suggest leaving GC grace high in case you do start doing
> deletes.
>
> Columns with TTL:s will disappear regardless of GC grace.
>
> If you do decide to run with short GC grace, be aware of the
> consequencues:
> http://wiki.apache.org/cassandra/Operations#Dealing_with_the_consequences_of_nodetool_repair_not_running_within_GCGraceSeconds
>
> --
> / Peter Schuller (@scode, http://worldmodscode.wordpress.com)
>
Re: TTL 3 hours + GC grace 0
Posted by Peter Schuller <pe...@infidyne.com>.
> I am using TTL 3 hours and GC grace 0 for a CF. I have a normal CF that has
> records with TTL 3 hours and I dont send any delete request. I just wonder
> if using GC grace 0 will cause any problem except extra Memory/IO/network
> load. I know that gc grace is for not transferring deleted records after a
> down node comes back. So I assumed that transferring expired records will
> not cause any problem.
>
> Do you have any idea? Thank you!
If you do not perform any deletes at all, a GC grace of 0 should be
fine. But if you don't, the GC grace should not really be relevant
either. So I suggest leaving GC grace high in case you do start doing
deletes.
Columns with TTL:s will disappear regardless of GC grace.
If you do decide to run with short GC grace, be aware of the
consequencues: http://wiki.apache.org/cassandra/Operations#Dealing_with_the_consequences_of_nodetool_repair_not_running_within_GCGraceSeconds
--
/ Peter Schuller (@scode, http://worldmodscode.wordpress.com)