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 a 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/a7c54f74d14b08b6/692881da5df525b4?lnk=gst&q=transaction+recovery#692881da5df525b4 > > 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]> > . > 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.
