1. How to use sharding partition key in a way that partitions end up in different nodes? You could, for example, create a table with a bucket column added to the partition key: Table distinct( hourNumber int, bucket int, //could be a 5 minute bucket for example key text, distinctValue long primary key ((hourNumber,bucket)) )
2. if i set gc_grace_seconds to 0, would it replace the row at memtable (not saving repeated rows in sstables) or it would be done at first compaction? Overlapping rows in the memtables are merged regardless of the gc_grace_seconds period. Setting gc_grace_seconds to 0 will immediately evict tombstones during compaction but will disable hints delivery. You should set gc_grace_seconds>max_hint_window_in_ms On Tue, Jun 19, 2018 at 7:23 AM, onmstester onmstester <onmstes...@zoho.com> wrote: > Two other questions: > 1. How to use sharding partition key in a way that partitions end up in > different nodes? > 2. if i set gc_grace_seconds to 0, would it replace the row at memtable > (not saving repeated rows in sstables) or it would be done at first > compaction? > > Sent using Zoho Mail <https://www.zoho.com/mail/> > > > ---- On Tue, 19 Jun 2018 08:16:28 +0430 *onmstester onmstester > <onmstes...@zoho.com <onmstes...@zoho.com>>* wrote ---- > > Can i set gc_grace_seconds to 0 in this case? because reappearing deleted > data has no impact on my Business Logic, i'm just either creating a new row > or replacing the exactly same row. > > Sent using Zoho Mail <https://www.zoho.com/mail/> > > > ---- On Wed, 13 Jun 2018 03:41:51 +0430 *Elliott Sims > <elli...@backblaze.com <elli...@backblaze.com>>* wrote ---- > > > > If this is data that expires after a certain amount of time, you probably > want to look into using TWCS and TTLs to minimize the number of tombstones. > Decreasing gc_grace_seconds then compacting will reduce the number of > tombstones, but at the cost of potentially resurrecting deleted data if the > table hasn't been repaired during the grace interval. You can also just > increase the tombstone thresholds, but the queries will be pretty > expensive/wasteful. > > On Tue, Jun 12, 2018 at 2:02 AM, onmstester onmstester < > onmstes...@zoho.com> wrote: > > > Hi, > > I needed to save a distinct value for a key in each hour, the problem with > saving everything and computing distincts in memory is that there > are too many repeated data. > Table schema: > Table distinct( > hourNumber int, > key text, > distinctValue long > primary key (hourNumber) > ) > > I want to retrieve distinct count of all keys in a specific hour and using > this data model it would be achieved by reading a single partition. > The problem : i can't read from this table, system.log indicates that more > than 100K tombstones read and no live data in it. The gc_grace time is > the default (10 days), so i thought decreasing it to 1 hour and run > compaction, but is this a right approach at all? i mean the whole idea of > replacing > some millions of rows. each 10 times in a partition again and again that > creates alot of tombstones just to achieve distinct behavior? > > Thanks in advance > > Sent using Zoho Mail <https://www.zoho.com/mail/> > > > >
