Column names are just optional for RowCounter job. To be more accurate, RowCounter is a KeyValueCounter. If no columns are specified, only the first KeyValues of each row are included, then get the RowCounter.
On Fri, Jul 30, 2010 at 9:28 AM, Ted Yu <[email protected]> wrote: > If someone can share the commandline for running RowCounter, that would be > great. > > Also, hbase shell count doesn't require column name. Why does RowCounter > require it ? > > Thanks > > On Thu, Jul 29, 2010 at 4:55 PM, Ryan Rawson <[email protected]> wrote: > >> Hi, >> >> That table appears to be empty. Eg: >> >> 10/07/29 22:38:43 INFO mapred.JobClient: Map input records=0 >> >> >> So back to the count issue... Counting in databases is a classic >> problem. Unless your DB system is keeping stats on how many >> inserts/deletes and thus how big it thinks the table is, you have to >> count all the rows by reading them. HBase is no different, and a >> little harder, because we have a variable length data format, so we >> can't just estimate row sizes from file sizes. Keeping distributed >> stats is not impossible, but certainly not on any priority list to be >> implemented - of course JIRAs/patches welcome etc. >> >> -ryan >> >> >> On Thu, Jul 29, 2010 at 3:48 PM, Ted Yu <[email protected]> wrote: >> > We use HBase 0.20.5 >> > >> > Here is the snippet from RowCounter output: >> > >> > 10/07/29 22:38:42 DEBUG client.HTable$ClientScanner: Finished with >> scanning >> > at REGION => {NAME => >> > >> '2__HB_NOINC_ORCL_SQLLDR_0728-THREEGPPSPEECHCALLS-1280408509541-0,DFF46493EB352D0E31CBFA4652E6EC06,1280412540858', >> > STARTKEY => 'DFF46493EB352D0E31CBFA4652E6EC06', ENDKEY => '', ENCODED => >> > 1375318608, TABLE => {{NAME => >> > '2__HB_NOINC_ORCL_SQLLDR_0728-THREEGPPSPEECHCALLS-1280408509541-0', >> FAMILIES >> > => [{NAME => 'd', COMPRESSION => 'GZ', VERSIONS => '2', TTL => >> '31536000', >> > BLOCKSIZE => '65536', IN_MEMORY => 'false', BLOCKCACHE => 'false'}, {NAME >> => >> > 'i', COMPRESSION => 'GZ', VERSIONS => '2', TTL => '31536000', BLOCKSIZE >> => >> > '65536', IN_MEMORY => 'false', BLOCKCACHE => 'false'}, {NAME => 'v', >> > COMPRESSION => 'GZ', VERSIONS => '2', TTL => '31536000', BLOCKSIZE => >> > '65536', IN_MEMORY => 'false', BLOCKCACHE => 'false'}]}} >> > 10/07/29 22:38:42 INFO mapred.TaskRunner: >> Task:attempt_local_0001_m_000000_0 >> > is done. And is in the process of commiting >> > 10/07/29 22:38:42 INFO mapred.LocalJobRunner: >> > 10/07/29 22:38:42 INFO mapred.TaskRunner: Task >> attempt_local_0001_m_000000_0 >> > is allowed to commit now >> > 10/07/29 22:38:42 INFO mapred.FileOutputCommitter: Saved output of task >> > 'attempt_local_0001_m_000000_0' to >> > file:/usr/local/hadoop/trunk.80-275066/hbase-0.20.5/rc >> > 10/07/29 22:38:42 INFO mapred.LocalJobRunner: >> > 10/07/29 22:38:42 INFO mapred.TaskRunner: Task >> > 'attempt_local_0001_m_000000_0' done. >> > 10/07/29 22:38:43 INFO mapred.JobClient: map 100% reduce 0% >> > 10/07/29 22:38:43 INFO mapred.JobClient: Job complete: job_local_0001 >> > 10/07/29 22:38:43 INFO mapred.JobClient: Counters: 6 >> > 10/07/29 22:38:43 INFO mapred.JobClient: FileSystemCounters >> > 10/07/29 22:38:43 INFO mapred.JobClient: FILE_BYTES_READ=1592883 >> > 10/07/29 22:38:43 INFO mapred.JobClient: FILE_BYTES_WRITTEN=1624956 >> > 10/07/29 22:38:43 INFO mapred.JobClient: Map-Reduce Framework >> > 10/07/29 22:38:43 INFO mapred.JobClient: Map input records=0 >> > 10/07/29 22:38:43 INFO mapred.JobClient: Spilled Records=0 >> > 10/07/29 22:38:43 INFO mapred.JobClient: Map input bytes=0 >> > 10/07/29 22:38:43 INFO mapred.JobClient: Map output records=0 >> > >> > [sjc1-hadoop8.sjc1:hadoop 3705]ls -l >> > /usr/local/hadoop/trunk.80-275066/hbase-0.20.5/rc/part-00000 >> > -rwxrwxrwx 1 hadoop users 0 Jul 29 22:38 >> > /usr/local/hadoop/trunk.80-275066/hbase-0.20.5/rc/part-00000 >> > >> > But there are many records in the table I was querying. >> > >> > Can someone comment ? >> > >> > On Thu, Jul 29, 2010 at 2:26 PM, Jean-Daniel Cryans <[email protected] >> >wrote: >> > >> >> In 0.89 you can specify CACHE for the count command. Set it higher (it >> >> defaults to 10 rows per call). >> >> >> >> Also you can use the RowCounter MR job. >> >> >> >> J-D >> >> >> >> On Thu, Jul 29, 2010 at 2:22 PM, Ted Yu <[email protected]> wrote: >> >> > Hi, >> >> > The count method in HBase shell is quite slow. >> >> > Is there a way to obtain count faster ? >> >> > >> >> > Thanks >> >> > >> >> >> > >> > -- Regards Angus
