simply about difficult
Let’s say we want to got working Apache Atlas instance with embedded Hbase & Solr on our machine. Notice, that you need to install JDK 8 before start. Go to the Apache Atlas GitHub page, and download the zip file with the source code of the latest stable release from here: https://github.com/apache/atlas/tags Important notice: DO […]
READ MOREIMPORTANT! If you trying to install Apache Atlas and receiving this error, there is a separate article: https://mchesnavsky.tech/apache-atlas-building-installing/ Suppose that we are faced with these exceptions. The first: The second: The third: The hbase-client cannot connect to the Zookeeper. You need to pay attention to the address: If there is a real Zookeeper instance at […]
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 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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