Hi Jonathan, What we need is ascending order. The problem that Chubert pointed out is that when we insert time series data into the htable, only the last tablet is busy, this is slower than inserting to serveral tablets stimutanously.
sincerely, Evan 2009/7/17 Jonathan Gray <[email protected]>: > If you want time descending order, just use Long.MAX_VALUE - stamp. > > When reading the value you will have to take Long.MAX_VALUE - stored_value = > stamp; > > JG > > Qingyan(Evan) Liu wrote: >> >> hi chubert, >> >> your comment is really valuable. I'm considering about how to leverage >> performance and analysis. Most of the time, we will scan over a series >> of time, for example, to count the distinct access IPs for the last >> month. (i.e. most of the tasks are time series analysis.) If the keys >> are sorted by time, then the analysis will be performed easily. If the >> keys are partitioned by <userid>, and mostly it's hard to iterate all >> userids, then it's harder to perform the same statistics. >> >> So.... I'm trying to find out a better solution. And welcome for any >> suggestions. Thanks. >> >> sincerely, >> Evan >> >> 2009/7/14 zsongbo <[email protected]>: >>> >>> Hi Qingyuan(Evan), >>> >>> In the slides, Case 5: access log, you use <time><INC_COUNTER> as the >>> rowkey. >>> >>> I think there is a problem: Since the accesslog events are generated by >>> time >>> sequence, the rowkey will be in Ascending sequence. Then when we >>> insert/load >>> the accesslog into HBase, there will be only one/the last Tablet are >>> busy. >>> Thus, the load is not balance. >>> >>> It may be diffcult to design the schema of HBase for accesslog, because >>> it >>> depend the applications very much. >>> >>> RowKey=<userid><time> may be a choice. >>> >>> Schubert Zhang >>> >>> On Tue, Jul 14, 2009 at 2:23 AM, stack <[email protected]> wrote: >>> >>>> Please add a link to the below either to presentations or articles up on >>>> the >>>> hbase wiki. >>>> >>>> Thanks for the excellent contribution filling a hole we have had in our >>>> documentation with a while now. >>>> >>>> Yours, >>>> St.Ack >>>> >>>> On Mon, Jul 13, 2009 at 11:08 AM, Qingyan(Evan) Liu >>>> <[email protected] >>>>> >>>>> wrote: >>>>> Dears, >>>>> >>>>> I've just finished some slides about some cases of designing hbase >>>>> table schemas. Please have a look here: >>>>> >>>> >>>> http://www.slideshare.net/hmisty/20090713-hbase-schema-design-case-studies >>>>> >>>>> The cases are mostly collected from websites. The reason I did this is >>>>> because I found there're no good guides for me to say how to design >>>>> hbase table schemas. >>>>> >>>>> Any suggestions or best practices that you wanna share are welcomed! >>>>> >>>>> Thanks a lot! >>>>> >>>>> sincerely, >>>>> Evan >>>>> >> >
