I would probably do this in a background thread and cache the results, that way when you have to render, you can just cache the latest results.
I don't know why Cassandra can't seem to be able to fetch large batch sizes, I've also run into these timeouts but reducing the batch size to 2k seemed to work for me. On Wed, Mar 18, 2015 at 1:24 PM, Mehak Mehta <meme...@cs.stonybrook.edu> wrote: > We have UI interface which needs this data for rendering. > So efficiency of pulling this data matters a lot. It should be fetched > within a minute. > Is there a way to achieve such efficiency > > > On Wed, Mar 18, 2015 at 4:06 AM, Ali Akhtar <ali.rac...@gmail.com> wrote: > >> Perhaps just fetch them in batches of 1000 or 2000? For 1m rows, it seems >> like the difference would only be a few minutes. Do you have to do this all >> the time, or only once in a while? >> >> On Wed, Mar 18, 2015 at 12:34 PM, Mehak Mehta <meme...@cs.stonybrook.edu> >> wrote: >> >>> yes it works for 1000 but not more than that. >>> How can I fetch all rows using this efficiently? >>> >>> On Wed, Mar 18, 2015 at 3:29 AM, Ali Akhtar <ali.rac...@gmail.com> >>> wrote: >>> >>>> Have you tried a smaller fetch size, such as 5k - 2k ? >>>> >>>> On Wed, Mar 18, 2015 at 12:22 PM, Mehak Mehta < >>>> meme...@cs.stonybrook.edu> wrote: >>>> >>>>> Hi Jens, >>>>> >>>>> I have tried with fetch size of 10000 still its not giving any >>>>> results. >>>>> My expectations were that Cassandra can handle a million rows easily. >>>>> >>>>> Is there any mistake in the way I am defining the keys or querying >>>>> them. >>>>> >>>>> Thanks >>>>> Mehak >>>>> >>>>> On Wed, Mar 18, 2015 at 3:02 AM, Jens Rantil <jens.ran...@tink.se> >>>>> wrote: >>>>> >>>>>> Hi, >>>>>> >>>>>> Try setting fetchsize before querying. Assuming you don't set it too >>>>>> high, and you don't have too many tombstones, that should do it. >>>>>> >>>>>> Cheers, >>>>>> Jens >>>>>> >>>>>> – >>>>>> Skickat från Mailbox <https://www.dropbox.com/mailbox> >>>>>> >>>>>> >>>>>> On Wed, Mar 18, 2015 at 2:58 AM, Mehak Mehta < >>>>>> meme...@cs.stonybrook.edu> wrote: >>>>>> >>>>>>> Hi, >>>>>>> >>>>>>> I have requirement to fetch million row as result of my query which >>>>>>> is giving timeout errors. >>>>>>> I am fetching results by selecting clustering columns, then why the >>>>>>> queries are taking so long. I can change the timeout settings but I need >>>>>>> the data to fetched faster as per my requirement. >>>>>>> >>>>>>> My table definition is: >>>>>>> *CREATE TABLE images.results (uuid uuid, analysis_execution_id >>>>>>> varchar, analysis_execution_uuid uuid, x double, y double, loc >>>>>>> varchar, w >>>>>>> double, h double, normalized varchar, type varchar, filehost varchar, >>>>>>> filename varchar, image_uuid uuid, image_uri varchar, image_caseid >>>>>>> varchar, >>>>>>> image_mpp_x double, image_mpp_y double, image_width double, image_height >>>>>>> double, objective double, cancer_type varchar, Area float, submit_date >>>>>>> timestamp, points list<double>, PRIMARY KEY >>>>>>> ((image_caseid),Area,uuid));* >>>>>>> >>>>>>> Here each row is uniquely identified on the basis of unique uuid. >>>>>>> But since my data is generally queried based upon *image_caseid *I >>>>>>> have made it partition key. >>>>>>> I am currently using Java Datastax api to fetch the results. But the >>>>>>> query is taking a lot of time resulting in timeout errors: >>>>>>> >>>>>>> Exception in thread "main" >>>>>>> com.datastax.driver.core.exceptions.NoHostAvailableException: All >>>>>>> host(s) >>>>>>> tried for query failed (tried: localhost/127.0.0.1:9042 >>>>>>> (com.datastax.driver.core.exceptions.DriverException: Timed out waiting >>>>>>> for >>>>>>> server response)) >>>>>>> at >>>>>>> com.datastax.driver.core.exceptions.NoHostAvailableException.copy(NoHostAvailableException.java:84) >>>>>>> at >>>>>>> com.datastax.driver.core.DefaultResultSetFuture.extractCauseFromExecutionException(DefaultResultSetFuture.java:289) >>>>>>> at >>>>>>> com.datastax.driver.core.DefaultResultSetFuture.getUninterruptibly(DefaultResultSetFuture.java:205) >>>>>>> at >>>>>>> com.datastax.driver.core.AbstractSession.execute(AbstractSession.java:52) >>>>>>> at QueryDB.queryArea(TestQuery.java:59) >>>>>>> at TestQuery.main(TestQuery.java:35) >>>>>>> Caused by: >>>>>>> com.datastax.driver.core.exceptions.NoHostAvailableException: All >>>>>>> host(s) >>>>>>> tried for query failed (tried: localhost/127.0.0.1:9042 >>>>>>> (com.datastax.driver.core.exceptions.DriverException: Timed out waiting >>>>>>> for >>>>>>> server response)) >>>>>>> at >>>>>>> com.datastax.driver.core.RequestHandler.sendRequest(RequestHandler.java:108) >>>>>>> at >>>>>>> com.datastax.driver.core.RequestHandler$1.run(RequestHandler.java:179) >>>>>>> at >>>>>>> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) >>>>>>> at >>>>>>> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) >>>>>>> at java.lang.Thread.run(Thread.java:744) >>>>>>> >>>>>>> Also when I try the same query on console even while using limit of >>>>>>> 2000 rows: >>>>>>> >>>>>>> cqlsh:images> select count(*) from results where >>>>>>> image_caseid='TCGA-HN-A2NL-01Z-00-DX1' and Area<100 and Area>20 limit >>>>>>> 2000; >>>>>>> errors={}, last_host=127.0.0.1 >>>>>>> >>>>>>> Thanks and Regards, >>>>>>> Mehak >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>> >>>>> >>>> >>> >> >
