simply about difficult
If you get an exception like this: Check this two things first: Is the path to the keytab correct? Does the process have permission to read the keyab? In my case it turned out that there was no keytab read permission in hdfs. Thanks Xavier Portebois.
READ MORELet’s imagine that you need to know the actual distribution of keys by regions of the HBase table. There is no direct way to find it. But you can use this workaround: you need to send scan queries with region boundaries: This code will display line by line the number of keys in each region of the […]
READ MORESuppose you need to run HBase utility class from Java code. Such a class will have a main() method, which we will use. For demonstrating, we will use RowSplitter class. Firstly, we need to add the hbase-server module (for example, version 1.2.3) to pom.xml: In some our own class, let’s call RegionSplitter’s main(): If you […]
READ MORESuppose, that you need to create an HBase table with a certain preliminary created number of regions. You can use RegionSplitter tool to do this. Running RegionSplitter from command line / shell An example of a call from the command line / shell: The pattern is: SPLITALGORITHM is a java class name of a class […]
READ MORELet’s say you need to create an HBase table with a certain constant number of regions. Regions pre-creation First, you need to create a table with a certain pre-created number of regions. You can use one of the createTable() method overloads for that: You can make the byte[][] splitKeys array as follows: We need to add […]
READ MOREYou may encounter an exception like this: Most likely, you have a versioning problem: you are using hbase-client version 2.x.x with the server version 1.x.x. Also, you are trying to call HBase Admin API functions. The fact is that the hbase-client version 2.x.x can send only regular get, scan, put, delete requests to the hbase […]
READ MOREIf you are looking for default scan request parameters, here they are: Parameter Default value startRow HConstants.EMPTY_START_ROW stopRow HConstants.EMPTY_END_ROW maxVersions 1 batch -1 allowPartialResults false storeLimit -1 storeOffset 0 caching -1 maxResultSize -1L cacheBlocks true reversed false timeRange TimeRange.allTime() asyncPrefetch null small false mvccReadPoint -1L limit -1 readType Scan.ReadType.DEFAULT needCursorResult false
READ MORELet’s say you need to get the name of hdfs cluster in an application. To do this, you need to get the org.apache.hadoop.conf.Configuration object: In the place we need, we get the fs.defaultFS property value:
READ MORELet’s say you need to run the distcp command: But as a result, you get an error like this: One of the non-obvious reasons for such an error may be that node1:8020 is not an active node. Recheck the hostname and run the command again.
READ MOREImagine, that you need to use the HBase client 1.x and gRPC in the same Java application. The code for connecting dependencies to Maven will look something like this: If you run the application and execute the request through the HBase client, there will be an exception: The problem is that hbase-client 1.x uses an earlier […]
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