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Import data from HBase

This topic provides an example of how to use Exchange to import Nebula Graph data stored in HBase.

Data set

This topic takes the basketballplayer dataset as an example.

In this example, the data set has been stored in HBase. All vertexes and edges are stored in the player, team, follow, and serve tables. The following are some of the data for each table.

hbase(main):002:0> scan "player"
ROW                                COLUMN+CELL
 player100                         column=cf:age, timestamp=1618881347530, value=42
 player100                         column=cf:name, timestamp=1618881354604, value=Tim Duncan
 player101                         column=cf:age, timestamp=1618881369124, value=36
 player101                         column=cf:name, timestamp=1618881379102, value=Tony Parker
 player102                         column=cf:age, timestamp=1618881386987, value=33
 player102                         column=cf:name, timestamp=1618881393370, value=LaMarcus Aldridge
 player103                         column=cf:age, timestamp=1618881402002, value=32
 player103                         column=cf:name, timestamp=1618881407882, value=Rudy Gay
 ...

hbase(main):003:0> scan "team"
ROW                                COLUMN+CELL
 team200                           column=cf:name, timestamp=1618881445563, value=Warriors
 team201                           column=cf:name, timestamp=1618881453636, value=Nuggets
 ...

hbase(main):004:0> scan "follow"
ROW                                COLUMN+CELL
 player100                         column=cf:degree, timestamp=1618881804853, value=95
 player100                         column=cf:dst_player, timestamp=1618881791522, value=player101
 player101                         column=cf:degree, timestamp=1618881824685, value=90
 player101                         column=cf:dst_player, timestamp=1618881816042, value=player102
 ...

hbase(main):005:0> scan "serve"
ROW                                COLUMN+CELL
 player100                         column=cf:end_year, timestamp=1618881899333, value=2016
 player100                         column=cf:start_year, timestamp=1618881890117, value=1997
 player100                         column=cf:teamid, timestamp=1618881875739, value=team204
 ...

Environment

This example is done on MacOS. Here is the environment configuration information:

  • Hardware specifications:
    • CPU: 1.7 GHz Quad-Core Intel Core i7
    • Memory: 16 GB
  • Spark: 2.4.7, stand-alone
  • Hadoop: 2.9.2, pseudo-distributed deployment
  • HBase: 2.2.7

Prerequisites

Before importing data, you need to confirm the following information:

  • Nebula Graph has been installed and deployed with the following information:

    • IP addresses and ports of Graph and Meta services.
    • The user name and password with write permission to Nebula Graph.
  • Spark has been installed.
  • Learn about the Schema created in Nebula Graph, including names and properties of Tags and Edge types, and more.
  • The Hadoop service has been installed and started.

Steps

Step 1: Create the Schema in Nebula Graph

Analyze the data to create a Schema in Nebula Graph by following these steps:

  1. Identify the Schema elements. The Schema elements in the Nebula Graph are shown in the following table.

    Element Name Property
    Tag player name string, age int
    Tag team name string
    Edge Type follow degree int
    Edge Type serve start_year int, end_year int
  2. Create a graph space basketballplayer in the Nebula Graph and create a Schema as shown below.

    ## Create a graph space.
    nebula> CREATE SPACE basketballplayer \
            (partition_num = 10, \
            replica_factor = 1, \
            vid_type = FIXED_STRING(30));
    
    ## Use the graph space basketballplayer.
    nebula> USE basketballplayer;
    
    ## Create the Tag player.
    nebula> CREATE TAG player(name string, age int);
    
    ## Create the Tag team.
    nebula> CREATE TAG team(name string);
    
    ## Create the Edge type follow.
    nebula> CREATE EDGE follow(degree int);
    
    ## Create the Edge type serve.
    nebula> CREATE EDGE serve(start_year int, end_year int);
    

For more information, see Quick start workflow.

Step 2: Modify configuration files

After Exchange is compiled, copy the conf file target/classes/application.conf to set HBase data source configuration. In this example, the copied file is called hbase_application.conf. For details on each configuration item, see Parameters in the configuration file.

{
  # Spark configuration
  spark: {
    app: {
      name: Nebula Exchange 2.6.1
    }
    driver: {
      cores: 1
      maxResultSize: 1G
    }
    cores {
      max: 16
    }
  }


  # Nebula Graph configuration
  nebula: {
    address:{
      # Specify the IP addresses and ports for Graph and all Meta services.
      # If there are multiple addresses, the format is "ip1:port","ip2:port","ip3:port".
      # Addresses are separated by commas.
      graph:["127.0.0.1:9669"]
      meta:["127.0.0.1:9559"]
    }
    # The account entered must have write permission for the Nebula Graph space.
    user: root
    pswd: nebula
    # Fill in the name of the graph space you want to write data to in the Nebula Graph.
    space: basketballplayer
    connection {
      timeout: 3000
      retry: 3
    }
    execution {
      retry: 3
    }
    error: {
      max: 32
      output: /tmp/errors
    }
    rate: {
      limit: 1024
      timeout: 1000
    }
  }
  # Processing vertexes
  tags: [
    # Set information about Tag player.
    # If you want to set RowKey as the data source, enter rowkey and the actual column name of the column family.
    {
      # The Tag name in Nebula Graph.
      name: player
      type: {
        # Specify the data source file format to HBase.
        source: hbase
        # Specify how to import the data into Nebula Graph: Client or SST.
        sink: client
      }
      host:192.168.*.*
      port:2181
      table:"player"
      columnFamily:"cf"

      # Specify the column names in the player table in fields, and their corresponding values are specified as properties in the Nebula Graph.
      # The sequence of fields and nebula.fields must correspond to each other.
      # If multiple column names need to be specified, separate them by commas.
      fields: [age,name]
      nebula.fields: [age,name]

      # Specify a column of data in the table as the source of vertex VID in the Nebula Graph.
      # For example, if rowkey is the source of the VID, enter rowkey.
      vertex:{
          field:rowkey
      }


      # Number of pieces of data written to Nebula Graph in a single batch.
      batch: 256

      # Number of Spark partitions
      partition: 32
    }
    # Set Tag Team information.
    {
      name: team
      type: {
        source: hbase
        sink: client
      }
      host:192.168.*.*
      port:2181
      table:"team"
      columnFamily:"cf"
      fields: [name]
      nebula.fields: [name]
      vertex:{
          field:rowkey
      }
      batch: 256
      partition: 32
    }

  ]

  # Processing edges
  edges: [
    # Set the information about the Edge Type follow.
    {
      # The corresponding Edge Type name in Nebula Graph.
      name: follow

      type: {
        # Specify the data source file format to HBase.
        source: hbase

        # Specify how to import the Edge type data into Nebula Graph.
        # Specify how to import the data into Nebula Graph: Client or SST.
        sink: client
      }

      host:192.168.*.*
      port:2181
      table:"follow"
      columnFamily:"cf"

      # Specify the column names in the follow table in fields, and their corresponding values are specified as properties in the Nebula Graph.
      # The sequence of fields and nebula.fields must correspond to each other.
      # If multiple column names need to be specified, separate them by commas.
      fields: [degree]
      nebula.fields: [degree]

      # In source, use a column in the follow table as the source of the edge's source vertex.
      # In target, use a column in the follow table as the source of the edge's destination vertex.
      source:{
          field:rowkey
      }


      target:{
          field:dst_player
      }


      # The number of data written to Nebula Graph in a single batch.
      batch: 256

      # The number of Spark partitions.
      partition: 32
    }

    # Set the information about the Edge Type serve.
    {
      name: serve
      type: {
        source: hbase
        sink: client
      }
      host:192.168.*.*
      port:2181
      table:"serve"
      columnFamily:"cf"

      fields: [start_year,end_year]
      nebula.fields: [start_year,end_year]
      source:{
          field:rowkey
      }

      target:{
          field:teamid
      }

      batch: 256
      partition: 32
    }
  ]
}

Step 3: Import data into Nebula Graph

Run the following command to import HBase data into Nebula Graph. For descriptions of the parameters, see Options for import.

${SPARK_HOME}/bin/spark-submit --master "local" --class com.vesoft.nebula.exchange.Exchange <nebula-exchange-2.6.1.jar_path> -c <hbase_application.conf_path>

Note

JAR packages are available in two ways: compiled them yourself, or download the compiled .jar file directly.

For example:

${SPARK_HOME}/bin/spark-submit  --master "local" --class com.vesoft.nebula.exchange.Exchange  /root/nebula-exchange/nebula-exchange/target/nebula-exchange-2.6.1.jar  -c /root/nebula-exchange/nebula-exchange/target/classes/hbase_application.conf

You can search for batchSuccess.<tag_name/edge_name> in the command output to check the number of successes. For example, batchSuccess.follow: 300.

Step 4: (optional) Validate data

Users can verify that data has been imported by executing a query in the Nebula Graph client (for example, Nebula Graph Studio). For example:

GO FROM "player100" OVER follow;

Users can also run the SHOW STATS command to view statistics.

Step 5: (optional) Rebuild indexes in Nebula Graph

With the data imported, users can recreate and rebuild indexes in Nebula Graph. For details, see Index overview.


Last update: October 22, 2021
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