Hi Jianwei, You may also want to take a look at the generic client transaction API being proposed in HBASE-11447: https://issues.apache.org/jira/browse/HBASE-11447
I think it would be useful to have the Themis perspective there, and whether the proposed API meets your needs and requirements. On Tue, Jul 8, 2014 at 9:10 AM, Ted Yu <yuzhih...@gmail.com> wrote: > Jianwei: > You may want to update the comment for ThemisScan : > > //a wrapper class of Put in HBase which not expose timestamp to user > public class ThemisScan extends ThemisRead { > > Is there plan to support append / increment as part of the transaction ? > > Currently Themis depends on 0.94.11 > Is there plan to support 0.96+ releases ? > > Thanks > > > On Tue, Jul 8, 2014 at 12:34 AM, 崔建伟 <cuijian...@xiaomi.com> wrote: > > > Hi everyone, I want to introduce our open-source project Themis which > > implements cross-row/corss-table transaction on HBase. > > > > Themis follows google's percolator algorithm( > > http://research.google.com/pubs/pub36726.html), which provides > > ACID-compliant transaction and snapshot isolation. The cross-row > > transaction is based on HBase's single-row atomic semantics and doesn't > use > > a central transaction server, so that supports linear-scalability. > > > > Themis depends on a timestamp server to provides global strictly > > incremental timestamp to define the order of transactions, which will be > > used to resolve the write-write and read-write conflicts. The timestamp > > server is lightweight and could achieve hight throughput(500, 000 + qps), > > and Themis will batch timestamp requests across transactions in one Rpc, > so > > that it won't become the bottleneck of the system even when processing > > billions of transactions every day. > > > > Although Themis could be implemented totally in client-side, we adopt > > coprocessor framework of HBase to achieve higher performance. Themis > > includes a client-side library to provides transaction APIs, such as > > themisPut/themisGet/themisScan/themisDelete, and a coprocessor library > > loaded on regionserver. Therefore, Themis could be used without changing > > the code and logic of HBase. > > > > We have been validating the correctness of Themis for a few months by a > > AccountTransfer simulation program, which concurrently does cross-row > > transactions by transferring money among different accounts(each account > is > > a row in HBase) and verifies total money of all accounts doesn't change > in > > the simulation. We have also run Themis on our production environment. > > > > We test the performance of Themis and get comparable result as > percolator. > > The single-column transaction represents the worst performance case for > > Themis compared with HBase, the result is: > > 1) For read, the performance of percolator is 90% of HBase; > > 2) For write, the performance of percolator is 23% of HBase. > > The write performance drops a lot because Themis uses two-phase commit > > protocol to achieve ACID of transaction. For multi-row write, we improve > > the performance by paralleling all writes of pre-write phase. For > > single-row write, we are optimizing two-phase commit protocol to achieve > > better performance and will update the result when it is ready. The > details > > of performance result could be found in github. > > > > The repository and introduction of Themis include: > > 1. Themis github: https://github.com/XiaoMi/themis/. The source code, > > performance test result and user guide could be found here. > > 2. Themis jira : https://issues.apache.org/jira/browse/HBASE-10999 > > 3. Chronos github: https://github.com/XiaoMi/chronos. Chronos is our > > open-source high-availability, high-performance timestamp server to > provide > > global strictly incremental timestamp for Themis. > > > > If you find Themis interesting, please leave us comment in the mail, jira > > or github. > > > > Best > > cuijianwei > > >