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Import data from ORC files

This topic provides an example of how to use Exchange to import Nebula Graph data stored in HDFS or local ORC files.

To import a local ORC file to Nebula Graph, see Nebula Importer.

Data set

This topic takes the basketballplayer dataset as an example.

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

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.
  • If files are stored in HDFS, ensure that the Hadoop service is running properly.
  • If files are stored locally and Nebula Graph is a cluster architecture, you need to place the files in the same directory locally on each machine in the cluster.

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: Process ORC files

Confirm the following information:

  1. Process ORC files to meet Schema requirements.

  2. Obtain the ORC file storage path.

Step 3: Modify configuration files

After Exchange is compiled, copy the conf file target/classes/application.conf to set ORC data source configuration. In this example, the copied file is called orc_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
    }
    executor: {
        memory: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 the information about the Tag player.
    {
      name: player
      type: {
        # Specify the data source file format to ORC.
        source: orc

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

      # Specify the path to the ORC file.
      # If the file is stored in HDFS, use double quotation marks to enclose the file path, starting with hdfs://. For example, "hdfs://ip:port/xx/xx".
      # If the file is stored locally, use double quotation marks to enclose the file path, starting with file://. For example, "file:///tmp/xx.orc".
      path: "hdfs://192.168.*.*:9000/data/vertex_player.orc"

      # Specify the key name in the ORC file in fields, and its corresponding value will serve as the data source for the properties specified in the Nebula Graph.
      # If multiple values need to be specified, separate them with commas.
      fields: [age,name]

      # Specify the property names defined in Nebula Graph.
      # The sequence of fields and nebula.fields must correspond to each other.
      nebula.fields: [age, name]

      # Specify a column of data in the table as the source of VIDs in the Nebula Graph.
      # The value of vertex must be consistent with the field in the ORC file.
      # Currently, Nebula Graph 2.6.1 supports only strings or integers of VID.
      vertex: {
        field:id
      }

      # 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 Tag team.
    {
      # Specify the Tag name defined in Nebula Graph.
      name: team
      type: {
        # Specify the data source file format to ORC.
        source: orc

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

      # Specify the path to the ORC file.
      # If the file is stored in HDFS, use double quotation marks to enclose the file path, starting with hdfs://. For example, "hdfs://ip:port/xx/xx".
      # If the file is stored locally, use double quotation marks to enclose the file path, starting with file://. For example, "file:///tmp/xx.orc".
      path: "hdfs://192.168.*.*:9000/data/vertex_team.orc"

      # Specify the key name in the ORC file in fields, and its corresponding value will serve as the data source for the properties specified in the Nebula Graph.
      # If multiple values need to be specified, separate them with commas.
      fields: [name]

      # Specify the property names defined in Nebula Graph.
      # The sequence of fields and nebula.fields must correspond to each other.
      nebula.fields: [name]

      # Specify a column of data in the table as the source of VIDs in the Nebula Graph.
      # The value of vertex must be consistent with the field in the ORC file.
      # Currently, Nebula Graph 2.6.1 supports only strings or integers of VID.
      vertex: {
        field:id
      }


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

      # The number of Spark partitions.
      partition: 32
    }



    # If more vertexes need to be added, refer to the previous configuration to add them.
  ]
  # Processing edges
  edges: [
    # Set the information about the Edge Type follow.
    {
      # Specify the Edge Type name defined in Nebula Graph.
      name: follow
      type: {
        # Specify the data source file format to ORC.
        source: orc

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

      # Specify the path to the ORC file.
      # If the file is stored in HDFS, use double quotation marks to enclose the file path, starting with hdfs://. For example, "hdfs://ip:port/xx/xx".
      # If the file is stored locally, use double quotation marks to enclose the file path, starting with file://. For example, "file:///tmp/xx.orc".
      path: "hdfs://192.168.*.*:9000/data/edge_follow.orc"

      # Specify the key name in the ORC file in fields, and its corresponding value will serve as the data source for the properties specified in the Nebula Graph.
      # If multiple values need to be specified, separate them with commas.
      fields: [degree]

      # Specify the property names defined in Nebula Graph.
      # The sequence of fields and nebula.fields must correspond to each other.
      nebula.fields: [degree]

      # Specify a column as the source for the source and destination vertexes.
      # The value of vertex must be consistent with the field in the ORC file.
      # Currently, Nebula Graph 2.6.1 supports only strings or integers of VID.
      source: {
        field: src
      }
      target: {
        field: dst
      }


      # (Optional) Specify a column as the source of the rank.
      #ranking: rank

      # 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.
    {
      # Specify the Edge type name defined in Nebula Graph.
      name: serve
      type: {
        # Specify the data source file format to ORC.
        source: orc

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

      # Specify the path to the ORC file.
      # If the file is stored in HDFS, use double quotation marks to enclose the file path, starting with hdfs://. For example, "hdfs://ip:port/xx/xx".
      # If the file is stored locally, use double quotation marks to enclose the file path, starting with file://. For example, "file:///tmp/xx.orc".
      path: "hdfs://192.168.*.*:9000/data/edge_serve.orc"

      # Specify the key name in the ORC file in fields, and its corresponding value will serve as the data source for the properties specified in the Nebula Graph.
      # If multiple values need to be specified, separate them with commas.
      fields: [start_year,end_year]

      # Specify the property names defined in Nebula Graph.
      # The sequence of fields and nebula.fields must correspond to each other.
      nebula.fields: [start_year, end_year]

      # Specify a column as the source for the source and destination vertexes.
      # The value of vertex must be consistent with the field in the ORC file.
      # Currently, Nebula Graph 2.6.1 supports only strings or integers of VID.
      source: {
        field: src
      }
      target: {
        field: dst
      }

      # (Optional) Specify a column as the source of the rank.
      #ranking: _c5


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

      # The number of Spark partitions.
      partition: 32
    }

  # If more edges need to be added, refer to the previous configuration to add them.
}

Step 4: Import data into Nebula Graph

Run the following command to import ORC data into Nebula Graph. For a description 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 <orc_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/orc_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 5: (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 6: (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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