Anoop: Only thing is that some mappers crashed.. So thin MR fw will run that mapper again on the same data set.. Then the unique id will be different?
Anil: Yes, for the same dataset also the UniqueId will be different. UniqueID does not depends on the data. Thanks, Anil Gupta On Tue, Oct 23, 2012 at 11:07 PM, Anoop John <[email protected]> wrote: > >. Is there a way that i can explicitly turn on WAL for bulk loading? > no.. > How you generate the unique id? Remember that initial steps wont need the > HBase cluster at all. MR generates the HFiles and the o/p will be in file > only.. Mappers also will write o/p to file... Only thing is that some > mappers crashed.. So thin MR fw will run that mapper again on the same data > set.. Then the unique id will be different? I think you no need to worry > about data loss from Hbase side.. So WAL is not required.. > > -Anoop- > > > > > On Wed, Oct 24, 2012 at 10:58 AM, anil gupta <[email protected]> > wrote: > > > That's a very interesting fact. You made it clear but my custom Bulk > Loader > > generates an unique ID for every row in map phase. So, all my data is not > > in csv or text. Is there a way that i can explicitly turn on WAL for bulk > > loading? > > > > On Tue, Oct 23, 2012 at 10:14 PM, Anoop John <[email protected]> > > wrote: > > > > > Hi Anil > > > In case of bulk loading it is not like data is put into > > > HBase one by one.. The MR job will create an o/p like HFile.. It will > > > create the KVs and write to file in order as how HFile will look like.. > > The > > > the file is loaded into HBase finally.. Only for this final step HBase > RS > > > will be used.. So there is no point in WAL there... I am making it > clear > > > for you? The data is already present in form of raw data in some txt > or > > > csv file :) > > > > > > -Anoop- > > > > > > On Wed, Oct 24, 2012 at 10:41 AM, Anoop John <[email protected]> > > > wrote: > > > > > > > Hi Anil > > > > > > > > > > > > > > > > On Wed, Oct 24, 2012 at 10:39 AM, anil gupta <[email protected] > > > >wrote: > > > > > > > >> Hi Anoop, > > > >> > > > >> As per your last email, did you mean that WAL is not used while > using > > > >> HBase > > > >> Bulk Loader? If yes, then how we ensure "no data loss" in case of > > > >> RegionServer failure? > > > >> > > > >> Thanks, > > > >> Anil Gupta > > > >> > > > >> On Tue, Oct 23, 2012 at 9:55 PM, ramkrishna vasudevan < > > > >> [email protected]> wrote: > > > >> > > > >> > As Kevin suggested we can make use of bulk load that goes thro WAL > > and > > > >> > Memstore. Or the second option will be to use the o/p of mappers > to > > > >> create > > > >> > HFiles directly. > > > >> > > > > >> > Regards > > > >> > Ram > > > >> > > > > >> > On Wed, Oct 24, 2012 at 8:59 AM, Anoop John < > [email protected]> > > > >> wrote: > > > >> > > > > >> > > Hi > > > >> > > Using ImportTSV tool you are trying to bulk load your data. > > Can > > > >> you > > > >> > see > > > >> > > and tell how many mappers and reducers were there. Out of total > > time > > > >> what > > > >> > > is the time taken by the mapper phase and by the reducer phase. > > > Seems > > > >> > like > > > >> > > MR related issue (may be some conf issue). In this bulk load > case > > > >> most of > > > >> > > the work is done by the MR job. It will read the raw data and > > > convert > > > >> it > > > >> > > into Puts and write to HFiles. MR o/p is HFiles itself. The next > > > part > > > >> in > > > >> > > ImportTSV will just put the HFiles under the table region > store.. > > > >> There > > > >> > > wont be WAL usage in this bulk load. > > > >> > > > > > >> > > -Anoop- > > > >> > > > > > >> > > On Tue, Oct 23, 2012 at 9:18 PM, Nick maillard < > > > >> > > [email protected]> wrote: > > > >> > > > > > >> > > > Hi everyone > > > >> > > > > > > >> > > > I'm starting with hbase and testing for our needs. I have set > > up a > > > >> > hadoop > > > >> > > > cluster of Three machines and A Hbase cluster atop on the same > > > three > > > >> > > > machines, > > > >> > > > one master two slaves. > > > >> > > > > > > >> > > > I am testing the Import of a 5GB csv file with the importTsv > > > tool. I > > > >> > > > import the > > > >> > > > file in the HDFS and use the importTsv tool to import in > Hbase. > > > >> > > > > > > >> > > > Right now it takes a little over an hour to complete. It > creates > > > >> > around 2 > > > >> > > > million entries in one table with a single family. > > > >> > > > If I use bulk uploading it goes down to 20 minutes. > > > >> > > > > > > >> > > > My hadoop has 21 map tasks but they all seem to be taking a > very > > > >> long > > > >> > > time > > > >> > > > to > > > >> > > > finish many tasks end up in time out. > > > >> > > > > > > >> > > > I am wondering what I have missed in my configuration. I have > > > >> followed > > > >> > > the > > > >> > > > different prerequisites in the documentations but I am really > > > >> unsure as > > > >> > > to > > > >> > > > what > > > >> > > > is causing this slow down. If I were to apply the wordcount > > > example > > > >> to > > > >> > > the > > > >> > > > same > > > >> > > > file it takes only minutes to complete so I am guessing the > > issue > > > >> lies > > > >> > in > > > >> > > > my > > > >> > > > Hbase configuration. > > > >> > > > > > > >> > > > Any help or pointers would by appreciated > > > >> > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > > >> > > > >> -- > > > >> Thanks & Regards, > > > >> Anil Gupta > > > >> > > > > > > > > > > > > > > > > > > > -- > > Thanks & Regards, > > Anil Gupta > > > -- Thanks & Regards, Anil Gupta
