Is this on a standalone instance or do you have fully distributed setup deployed? Do you have any kind of monitoring in place?
>From the numbers you are giving, it looks like the data is of the order of a >few 10 MBs, assuming this is a single threaded read. Did you write more data >between the first run (with cache disabled) and the second run (with cache >enabled)? It is possible that the data was in the memstore and not yet flushed >to HFiles when you did the first test. The memstore flushed and now the reads >had to go to disk since the cache was not yet warmed up with that data. >Subsequent reads of the same rows should be faster in that case. On Sunday, June 24, 2012 at 11:11 PM, Prakrati Agrawal wrote: > Dear all > > I am trying to optimize the retrieval code in Java for HBase. The following > are the timings without cache enabled: > The time taken to get 175347 columns of a row key is 677 ms > The time taken to get rows : 99 and columns: 14888573 is 48806 ms > The time taken to get all data (rows: 396 and columns: 32611576) is 96469 ms > > The time taken after caching is enabled(Both block and setCaching) : > The time taken to get 175347 columns of a row key is 713 ms > The time taken to get rows : 99 and columns: 14888573 is 57649 ms > The time taken to get all data (rows: 396 and columns: 32611576) is 111056 ms > > As you all can see, time increases after I enable caching. I am not > understanding what I am doing wrong. Please help me > > Thanks and Regards > Prakrati > > > ________________________________ > This email message may contain proprietary, private and confidential > information. The information transmitted is intended only for the person(s) > or entities to which it is addressed. Any review, retransmission, > dissemination or other use of, or taking of any action in reliance upon, this > information by persons or entities other than the intended recipient is > prohibited and may be illegal. If you received this in error, please contact > the sender and delete the message from your system. > > Mu Sigma takes all reasonable steps to ensure that its electronic > communications are free from viruses. However, given Internet accessibility, > the Company cannot accept liability for any virus introduced by this e-mail > or any attachment and you are advised to use up-to-date virus checking > software.
