1. yes, I have 20 concurrent running mappers. 2. I can't add more mappers because I set io.sort.mb to 500mb and if I set 8 mappers, it hit oov exception and load average is high 3. fast mapper only use 1 minute. following is the statistics HBase Counters REMOTE_RPC_CALLS 0 RPC_CALLS 523 RPC_RETRIES 0 NOT_SERVING_REGION_EXCEPTION 0 NUM_SCANNER_RESTARTS 0 MILLIS_BETWEEN_NEXTS 62,415 BYTES_IN_RESULTS 1,380,694,667 BYTES_IN_REMOTE_RESULTS 0 REGIONS_SCANNED 1 REMOTE_RPC_RETRIES 0
FileSystemCounters FILE_BYTES_READ 120,508,552 HDFS_BYTES_READ 176 FILE_BYTES_WRITTEN 241,000,600 File Input Format Counters Bytes Read 0 Map-Reduce Framework Map output materialized bytes 120,448,992 Combine output records 0 Map input records 5,208,607 Physical memory (bytes) snapshot 965,730,304 Spilled Records 10,417,214 Map output bytes 282,122,973 CPU time spent (ms) 82,610 Total committed heap usage (bytes) 1,061,158,912 Virtual memory (bytes) snapshot 1,681,047,552 Combine input records 0 Map output records 5,208,607 SPLIT_RAW_BYTES 176 On Tue, Jul 22, 2014 at 12:11 PM, Stack <[email protected]> wrote: > How many regions now? > > You still have 20 concurrent mappers running? Are your machines loaded w/ > 4 map tasks on each? Can you up the number of concurrent mappers? Can you > get an idea of your scan rates? Are all map tasks scanning at same rate? > Does one task lag the others? Do you emit stats on each map task such as > rows processed? Can you figure your bottleneck? Are you seeking disk all > the time? Anything else running while this big scan is going on? How big > are your cells? Do you have one or more column families? How many columns? > > For average region size, do du on the hdfs region directories and then sum > and divide by region count. > > St.Ack > > > On Mon, Jul 21, 2014 at 7:30 PM, Li Li <[email protected]> wrote: > >> anyone could help? now I have about 1.1 billion nodes and it takes 2 >> hours to finish a map reduce job. >> >> ---------- Forwarded message ---------- >> From: Li Li <[email protected]> >> Date: Thu, Jun 26, 2014 at 3:34 PM >> Subject: how to do parallel scanning in map reduce using hbase as input? >> To: [email protected] >> >> >> my table has about 700 million rows and about 80 regions. each task >> tracker is configured with 4 mappers and 4 reducers at the same time. >> The hadoop/hbase cluster has 5 nodes so at the same time, it has 20 >> mappers running. it takes more than an hour to finish mapper stage. >> The hbase cluster's load is very low, about 2,000 request per second. >> I think one mapper for a region is too small. How can I run more than >> one mapper for a region so that it can take full advantage of >> computing resources? >>
