Ted: Yes, I've already read the HBase documentation, but didn't find anything that directly answered my question. My question was simply whether it's possible to get cells with the same timestamp with concurrent Puts to the same cell.
Vlad: Thanks for the information. Yep, I've also noticed the behavior of the last-write-wins when testing directly in hbase shell and writing out two values to the same cell with an identical timestamp. So, I gather that an application writing to the same cell concurrently will result in potential data loss when the write is at the exact same millisecond, correct? For my use-case, I'm not necessarily looking for uniqueness for the timestamp, but want to ensure I can still access all versions of the cell, even ones with the same timestamp. Dia On Thu, Jun 4, 2015 at 7:05 PM, Vladimir Rodionov <[email protected]> wrote: > >> Please read http://hbase.apache.org/book.html#_store > > How does this answer original question? > > -Vlad > > On Thu, Jun 4, 2015 at 6:30 PM, Ted Yu <[email protected]> wrote: > > > Dia: > > Please read http://hbase.apache.org/book.html#_store > > > > Cheers > > > > On Thu, Jun 4, 2015 at 6:02 PM, Vladimir Rodionov < > [email protected]> > > wrote: > > > > > Yes, last write wins (with higher sequenceId). MemStore will resolve > this > > > conflict and only the last > > > put will be added eventually, unless ... between these two puts > > MemStore's > > > snapshot is created. > > > I this case put #1 will be saved in a snapshot and eventually will > make > > it > > > into a store file, but this is just my speculations. > > > > > > -Vlad > > > > > > On Thu, Jun 4, 2015 at 5:08 PM, Dia Kharrat <[email protected]> > wrote: > > > > > > > I'm trying to confirm the behavior of HBase when there are concurrent > > > > writes to the same cell that happen at the exact same millisecond and > > not > > > > providing a timestamp value to the Put operations (i.e. relying on > > > current > > > > time of region server). Is it possible that such concurrent writes > > result > > > > in a cell with an identical version value or does HBase have a > > mechanism > > > to > > > > protect against that? > > > > > > > > If that's the case, my understanding is that last write wins, > correct? > > > > > > > > Thanks, > > > > Dia > > > > > > > > > >
