Yes, that's what I meant, but correct me if I'm wrong, when a deletion comes after another deletion for the same row or column will the gc-before count against the last one, isn't it?
Maybe knowing that all the subsequent versions of a deletion are deletions too, it could take the first timestamp against the gc-grace-seconds when is reducing & compacting. // Germán Kondolf http://twitter.com/germanklf http://code.google.com/p/seide/ // @i4 On 19/01/2011, at 00:16, Jonathan Ellis <jbel...@gmail.com> wrote: > If you mean that multiple tombstones for the same row or column should > be merged into a single one at compaction time, then yes, that is what > happens. > > On Tue, Jan 18, 2011 at 7:53 PM, Germán Kondolf > <german.kond...@gmail.com> wrote: >> Maybe it could be taken into account when the compaction is executed, >> if I only have a consecutive list of uninterrupted tombstones it could >> only care about the first. It sounds like the-way-it-should-be, maybe >> as a part of the "row-reduce" process. >> >> Is it feasible? Looking into the CASSANDRA-1074 sounds like it should. >> >> //GK >> http://twitter.com/germanklf >> http://code.google.com/p/seide/ >> >> On Tue, Jan 18, 2011 at 10:55 AM, Sylvain Lebresne <sylv...@riptano.com> >> wrote: >>> On Tue, Jan 18, 2011 at 2:41 PM, David Boxenhorn <da...@lookin2.com> wrote: >>>> Thanks, Aaron, but I'm not 100% clear. >>>> >>>> My situation is this: My use case spins off rows (not columns) that I no >>>> longer need and want to delete. It is possible that these rows were never >>>> created in the first place, or were already deleted. This is a very large >>>> cleanup task that normally deletes a lot of rows, and the last thing that I >>>> want to do is create tombstones for rows that didn't exist in the first >>>> place, or lengthen the life on disk of tombstones of rows that are already >>>> deleted. >>>> >>>> So the question is: before I delete, do I have to retrieve the row to see >>>> if >>>> it exists in the first place? >>> >>> Yes, in your situation you do. >>> >>>> >>>> >>>> >>>> On Tue, Jan 18, 2011 at 11:38 AM, Aaron Morton <aa...@thelastpickle.com> >>>> wrote: >>>>> >>>>> AFAIK that's not necessary, there is no need to worry about previous >>>>> deletes. You can delete stuff that does not even exist, neither >>>>> batch_mutate >>>>> or remove are going to throw an error. >>>>> All the columns that were (roughly speaking) present at your first >>>>> deletion will be available for GC at the end of the first tombstones life. >>>>> Same for the second. >>>>> Say you were to write a col between the two deletes with the same name as >>>>> one present at the start. The first version of the col is avail for GC >>>>> after >>>>> tombstone 1, and the second after tombstone 2. >>>>> Hope that helps >>>>> Aaron >>>>> On 18/01/2011, at 9:37 PM, David Boxenhorn <da...@lookin2.com> wrote: >>>>> >>>>> Thanks. In other words, before I delete something, I should check to see >>>>> whether it exists as a live row in the first place. >>>>> >>>>> On Tue, Jan 18, 2011 at 9:24 AM, Ryan King <r...@twitter.com> wrote: >>>>>> >>>>>> On Sun, Jan 16, 2011 at 6:53 AM, David Boxenhorn <da...@lookin2.com> >>>>>> wrote: >>>>>>> If I delete a row, and later on delete it again, before GCGraceSeconds >>>>>>> has >>>>>>> elapsed, does the tombstone live longer? >>>>>> >>>>>> Each delete is a new tombstone, which should answer your question. >>>>>> >>>>>> -ryan >>>>>> >>>>>>> In other words, if I have the following scenario: >>>>>>> >>>>>>> GCGraceSeconds = 10 days >>>>>>> On day 1 I delete a row >>>>>>> On day 5 I delete the row again >>>>>>> >>>>>>> Will the tombstone be removed on day 10 or day 15? >>>>>>> >>>>> >>>> >>>> >>> >> > > > > -- > Jonathan Ellis > Project Chair, Apache Cassandra > co-founder of Riptano, the source for professional Cassandra support > http://riptano.com
