A simpler question would be this: Given:
* a set timeframe in the past (2-3 days roughly a year ago) * we are NOT removing records from the table at all * We ARE inserting into this table actively Should I expect two consecutive runs of the rowcounter mapreduce job to return an identical number? Andrew Kettmann Consultant, Platform Services Group From: Andrew Kettmann Sent: Thursday, February 08, 2018 11:35 AM To: user@hbase.apache.org Subject: Inconsistent rows exported/counted when looking at a set, unchanged past time frame. First the version details: Running HBASE/Yarn/HDFS using Cloudera manager 5.12.1. Hbase: Version 1.2.0-cdh5.8.0 HDFS/YARN: Hadoop 2.6.0-cdh5.8.0 Hbck and hdfs fsck return healthy 15 nodes, sized down recently from 30 (other service requirements reduced. Solr, etc) The simplest example of the inconsistency is using rowcounter. If I run the same mapreduce job twice in a row, I get different counts: hbase org.apache.hadoop.hbase.mapreduce.Driver rowcounter -Dmapreduce.map.speculative=false TABLENAME --starttime=1485907200000 --endtime=1486058400000 Looking at org.apache.hadoop.hbase.mapreduce.RowCounter$RowCounterMapper$Counters: Run 1: 4876683 Run 2: 4866351 Similarly with exports of the same date/time. Consecutive runs of the export get different results: hbase org.apache.hadoop.hbase.mapreduce.Export \ -Dmapred.map.tasks.speculative.execution=false \ -Dmapred.reduce.tasks.speculative.execution=false \ TABLENAME \ HDFSPATH 1 1485907200000 1486058400000 From Map Input/output records: Run 1: 4296778 Run 2: 4297307 None of the results show anything for spilled records, no failed maps. Sometimes the row count increases, sometimes it decreases. We aren’t using any row filter queries, we just want to export chunks of the data for a specific time range. This table is actively being read/written to, but I am asking about a date range in early 2017 in this case, so that should have no impact I would have thought. Another point is that the rowcount job and the export return ridiculously different numbers. There should be no older versions of rows involved as we are set to only keep the newest, and I can confirm that there are rows that are consistently missing from the exports. Table definition is below. hbase(main):001:0> describe 'TABLENAME' Table TABLENAME is ENABLED TABLENAME COLUMN FAMILIES DESCRIPTION {NAME => 'text', DATA_BLOCK_ENCODING => 'NONE', BLOOMFILTER => 'ROW', REPLICATION_SCOPE => '0', COMPRESSION => 'SNAPPY', VERSIONS => '1', MIN_VERSIONS => '0', TTL => 'FOREVER', KEEP_DELETED_CELLS => 'FALSE', BLO CKSIZE => '65536', IN_MEMORY => 'false', BLOCKCACHE => 'true'} 1 row(s) in 0.2800 seconds Any advice/suggestions would be greatly appreciated, are some of my assumptions wrong regarding import/export and that it should be consistent given consistent date/times? Andrew Kettmann Platform Services Group