Hypertable is designed in such a way that it could support row level transactions. We currently do not have any transaction API. The row would be all cells with the same row key (like Bigtable).
- Doug On Thu, Mar 4, 2010 at 1:34 AM, Harshada <[email protected]> wrote: > Thanks Doug. > > The previous discussion suggests that-> Hypertable provides row level > transactions. (i.e. the consistency is provided at the level of a row > --correct me if I am wrong) > Here, what does a row mean? The complete row corresponding to a single > key i.e. all the columns and all the revisions (like BigTable) or a > key and one particular version(timestamp). > > On Feb 2, 8:17 pm, Doug Judd <[email protected]> wrote: > > Hi Harshada, > > > > Hypertable currently doesn't support ACID transactions. We've carefully > > designed the system so that it could support transactions in the future. > > All updates go into a commit log in the DFS for durability. Each cell > has a > > 64-bit revision number associated with it. We use this revision number > for > > snapshot isolation, to support Multi-version concurrency control (MVCC). > > It's possible for the revision number to be supplied with inserts and > > queries. We envision some day building a transaction monitor that sits > in > > front of a Hypertable cluster to provide distributed transactions. > > > > It's also fairly simple to provide row-level transactions. All of the > data > > for a given row resides in the same range. This allows us to easily > build > > row-level transaction mechanism. On our near term roadmap, we plan to > add > > support for integer counters and an atomic increment operation, which is > > essentially a specialized transaction. We may build that on top of a > more > > generalized row-level read-modify-write mechanism as described in the > > Bigtable paper. > > > > Is there a specific transaction use case that you would like to see > > supported? > > > > - Doug > > > > On Mon, Feb 1, 2010 at 9:20 PM, Harshada <[email protected]> > wrote: > > > Hi, > > > > > I am new to this field. So, please pardon me if my questions are too > > > naive. > > > > >http://groups.google.com/group/hypertable-user/browse_thread/thread/a. > .. > > > > > tells us that Hypertable supports simple row/range level transactions. > > > > > My questions are: > > > > > 1. Is it like the traditional transaction support- i.e. including > > > locking, logging, recovery etc? If yes, where can I find related files > > > in the source? > > > 2. Is it similar/on the parallel lines of BigTable's tablet level > > > transaction support? > > > > > Thanks, > > > > > Harshada > > > > > -- > > > You received this message because you are subscribed to the Google > Groups > > > "Hypertable Development" group. > > > To post to this group, send email to [email protected]. > > > To unsubscribe from this group, send email to > > > [email protected]<hypertable-dev%[email protected]> > <hypertable-dev%[email protected]<hypertable-dev%[email protected]> > > > > > . > > > For more options, visit this group at > > >http://groups.google.com/group/hypertable-dev?hl=en. > > -- > You received this message because you are subscribed to the Google Groups > "Hypertable Development" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]<hypertable-dev%[email protected]> > . > For more options, visit this group at > http://groups.google.com/group/hypertable-dev?hl=en. > > -- You received this message because you are subscribed to the Google Groups "Hypertable Development" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/hypertable-dev?hl=en.
