hbase

问题 Is it possible to read data from HBase based on rowKey and columnFamily . Currently I access records by rowkey by this code: HTable table = new HTable(conf, "tablename"); Get get = new Get(rowkey.getBytes()); Result rs = table.get(get); for (KeyValue kv : rs.raw()) { holdvalue = new String(kv.getValue()); } I want to add columnfamily as a filter to access specific records that belongs to that specific rowKey and columnFamily . How could I achieve this? Thanks in advance 回答1: You can add the

问题 I want to call hbase org.apache.hadoop.hbase.mapreduce.LoadIncrementalHFiles /user/myuser/map_data/hfiles mytable method from my Java client code. When I run the application I get the following exception: org.apache.hadoop.hbase.io.hfile.CorruptHFileException: Problem reading HFile Trailer from file webhdfs://myserver.de:50070/user/myuser/map_data/hfiles/b/b22db8e263b74a7dbd8e36f9ccf16508 at org.apache.hadoop.hbase.io.hfile.HFile.pickReaderVersion(HFile.java:477) at org.apache.hadoop.hbase.io

问题 Is there any way to limit the number of columns under a particular row in Hbase? I have seen methods to limit rows. I wonder if there is any ways i can limit column family values Like, row columnfamily(page) value 1 page:1 1 1 page:2 2 1 page:3 3 I need to retrieve row1 values for column families page:1 and page:2 Is it possible? 回答1: There are a number of different ways that you can go with this problem. Basically, you want a server-side filter to limit your return data in a Get/Scan.

问题 I have taken the Hbase table backup using Hbase Export utility tool . hbase org.apache.hadoop.hbase.mapreduce.Export "FinancialLineItem" "/project/fricadev/ESGTRF/EXPORT" This has kicked in mapreduce and transferred all my table data into Output folder . As per the document the file format will of the ouotput file is sequence file . So i ran below code to extract my key and value from the file . Now i want to run mapreduce to read the key value from the output file but getting below exception

问题 Following with this link https://cwiki.apache.org/confluence/display/Hive/HBaseIntegration#HBaseIntegration-HiveMAPtoHBaseColumnFamily I'm trying to integrate hive and hbase, I have this configuration in hive-site.xml: <property> <name>hive.aux.jars.path</name> <value> file:///$HIVE_HOME/lib/hive-hbase-handler-2.0.0.jar, file:///$HIVE_HOME/lib/hive-ant-2.0.0.jar, file:///$HIVE_HOME/lib/protobuf-java-2.5.0.jar, file:///$HIVE_HOME/lib/hbase-client-1.1.1.jar, file:///$HIVE_HOME/lib/hbase-common

问题 Recently my team is using hbase-indexer on CDH for indexing hbase table column to solr . When we deploy hbase-indexer server (which is called Key-Value Store Indexer) and begin testing. We found a situation that the rows size between hbase table and solr index is different : We used Phoenix to count hbase table rows: 0: jdbc:phoenix:slave1,slave2,slave3:2181> SELECT /*+ NO_INDEX */ COUNT(1) FROM C_PICRECORD; +------------------------------------------+ | COUNT(1) | +--------------------------

问题 The following worked in HBase shell, when try to perform range scan on HBase shell. scan 'mytable', {STARTROW => "\x00\x00\x00\x00\x01\x8F\xF6\x83", ENDROW => "\x00\x00\x00\x00\x01\x8F\xF6\x8D"} But when try to implement Java client to perform the same, it retrieves no result. Scan scan = new Scan(Bytes.ToBytes("\x00\x00\x00\x00\x01\x8F\xF6\x83"),Bytes.toBytes("\x00\x00\x00\x00\x01\x8F\xF6\x8D"); scan.setFilter(colFilter); scan.setOtherStuff... ResultScanner scanner = table.getScanner(scan);

问题 Can I write output to multiple tables in HBase from my reducer? I went through different blog posts, but ma not able to find a way, even using MultiTableOutputFormat . I referred to this : Write to multiple tables in HBASE But not able to figure out the API signature for context.write call. Reducer code: public class MyReducer extends TableReducer<Text, Result, Put> { private static final Logger logger = Logger.getLogger( MyReducer.class ); @SuppressWarnings( "deprecation" ) @Override

问题 Is it right that Cassandra is good for write and less read, whereas HBASE is good for random read and write? Heard that facebook replaces Cassandra with HBASE 回答1: Yes: fb started building Cassandra, put it OpenSource, and migrated to HBase later on. I'm not exactly sure why but Cassandra and HBase are both good solutions. Cassandra has benefits being + HA (no SPOF), + having tunable Consistency, and + doing writes faster than reads (both are rather fast) - But Cassandra may increase network

问题 I have created a HBase by mentioning the default versions as 10 create 'tablename',{NAME => 'cf', VERSIONS => 10} and inserted two rows(row1 and row2) put 'tablename','row1','cf:id','row1id' put 'tablename','row1','cf:name','row1name' put 'tablename','row2','cf:id','row2id' put 'tablename','row2','cf:name','row2name' put 'tablename','row2','cf:name','row2nameupdate' put 'tablename','row2','cf:name','row2nameupdateagain' put 'tablename','row2','cf:name','row2nameupdateonemoretime' Tried to