Whether Omid fits the bill is open to discussion. We should revisit HBASE-2315 and provide the support Flavio, et al need.
Cheers On Tue, Jan 17, 2012 at 1:41 PM, Lars George <[email protected]> wrote: > Hi Ted, > > Wouldn't Omid (https://github.com/yahoo/omid) help there? Or is that too > broad? Just curious. > > Lars > > On Jan 17, 2012, at 4:36 PM, Ted Yu wrote: > > > Can we collect use case for 'limited cross row transactions' first ? > > > > I have been thinking about (unlimited) multi-row transaction support in > > HBase. It may not be a one-man task. But we should definitely implement > it > > someday. > > > > Cheers > > > > On Tue, Jan 17, 2012 at 1:27 PM, lars hofhansl <[email protected]> > wrote: > > > >> I just committed HBASE-5203 (together with HBASE-3584 this implements > >> atomic row operations). > >> Although a relatively small patch it lays the groundwork for > heterogeneous > >> operations in a single WALEdit. > >> > >> The interesting part is that even though the code enforced the atomic > >> operation to be a for single row, this is not required. > >> It is enough if all involved KVs reside in the same region. > >> > >> I am not saying that we should add any high level concept to HBase (such > >> as the EntityGroups of Megastore). > >> > >> But, with a slight addition to the API (allowing a grouping of multiple > >> row operations) client applications have all the building blocks to do > >> limited cross row atomic operations. > >> The client application would be responsible for either correctly > >> pre-splitting the table, or a custom balancer has to be provided. > >> > >> The operation would fail if the regionserver determines that it would > need > >> data from multiple region servers. > >> > >> I think this needs at least minimal support from HBase and cannot > >> (efficiently or without adding more moving parts) by a client API only. > >> > >> > >> Comments? Is this worth pursuing? If so, I'll file a jira and provide a > >> patch. > >> > >> Thanks. > >> > >> > >> -- Lars > >> > >> > >
