Using the Linux gsql Client to Connect to a Cluster

(Optional) Preparing an ECS as the gsql Client Server

For details about how to create an ECS, see "Getting Started > Creating an ECS" in the Elastic Cloud Server User Guide.

The created ECS must meet the following requirements:

• The ECS and data warehouse cluster must belong to the same region and AZ.
• If you use the gsql client provided by GaussDB(DWS) to connect to the GaussDB(DWS) cluster, the ECS image must meet the following requirements:

  The image's OS must be one of the following Linux OSs supported by the gsql client:

  • The Redhat x86_64 client can be used on the following OSs:
    • RHEL 6.4~7.6
    • CentOS 6.4~7.4
    • EulerOS 2.3
  • The SUSE x86_64 client can be used on the following OSs:
    • SLES 11.1~11.4
    • SLES 12.0~12.3
• If the client accesses the cluster using the private network address, ensure that the created ECS is in the same VPC as the GaussDB(DWS) cluster.

  For details about VPC operations, see "VPC and Subnet" in the Virtual Private Cloud User Guide.

• If the client accesses the cluster using the public network address, ensure that both the created ECS and GaussDB(DWS) cluster have an EIP.

  When creating an ECS, set EIP to Automatically assign or Specify.

• The security group rules of the ECS must enable communication between the ECS and the port that the GaussDB(DWS) cluster uses to provide services.

  For details about security group operations, see "Security Group" in the Virtual Private Cloud User Guide.

  Ensure that the security group of the ECS contains rules meeting the following requirements. If the rules do not exist, add them to the security group:

  • Transfer Direction: Outbound
  • Protocol: The protocol must contain TCP. For example, TCP or All.
  • Port: The value must contain the database port that provides services in the GaussDB(DWS) cluster. For example, set this parameter to 1-65535 or a specific GaussDB(DWS) database port.
  • Destination: The IP address set here must contain the IP address of the GaussDB(DWS) cluster to be connected. 0.0.0.0/0 indicates any IP address.
• The security group rules of the data warehouse cluster must ensure that GaussDB(DWS) can receive network access requests from clients.
  Ensure that the cluster's security group contains rules meeting the following requirements. If the rules do not exist, add them to the security group:

  • Transfer Direction: Inbound
  • Protocol: The protocol must contain TCP. For example, TCP or All.
  • Port: Set this parameter to the database port that provides services in the data warehouse cluster, for example, 8000.
  • Source: The IP address set here must contain the IP address of the GaussDB(DWS) client server, for example, 192.168.0.10/32.

Downloading the Linux gsql Client and Connecting to a Cluster

1. Download the Linux gsql client by referring to Downloading the Data Studio client, and use an SSH file transfer tool (such as WinSCP) to upload the client to a target Linux server.

   You are advised to download the gsql tool that matches the cluster version. That is, use gsql 8.1.x for clusters of 8.1.0 or later, and use gsql 8.2.x for clusters of 8.2.0 or later. To download gsql 8.2.x, replace dws_client_8.1.x_redhat_x64.zip with dws_client_8.2.x_redhat_x64.zip. The dws_client_8.1.x_redhat_x64.zip is used as an example.

   The user who uploads the client must have the full control permission on the target directory on the host to which the client is uploaded.

2. Use the SSH tool to remotely manage the host where the client is installed.

   For details about how to log in to an ECS, see "ECSs> Logging In to a Linux ECS > Login Using an SSH Password" in the Elastic Cloud Server User Guide.

3. (Optional) To connect to the cluster in SSL mode, configure SSL authentication parameters on the host where the client is installed. For details, see Establishing Secure TCP/IP Connections in SSL Mode.
   

   The SSL connection mode is more secure than the non-SSL mode. You are advised to connect the client to the cluster in SSL mode.

4. Run the following commands to decompress the client:

   cd <Path for saving the client>
   unzip dws_client_8.1.x_redhat_x64.zip

   In the preceding commands:

   • <Path_for_storing_the_client>: Replace it with the actual path.
   • dws_client_8.1.x_redhat_x64.zip: This is the client tool package name of RedHat x86. Replace it with the actual name.

5. Run the following command to configure the GaussDB(DWS) client:

   source gsql_env.sh

   If the following information is displayed, the gsql client is successfully configured:

   All things done.

6. Connect to the database in the GaussDB(DWS) cluster using the gsql client. Replace the values of each parameter with actual values.

   gsql -d <Database_name> -h <Cluster_address> -U <Database_user> -p <Database_port> -W <Cluster_password> -r

   The parameters are described as follows:

   • Database_name: Enter the name of the database to be connected. If you use the client to connect to the cluster for the first time, enter the default database gaussdb.
   • Cluster_address: For details about how to obtain this address, see Obtaining the Cluster Connection Address. If a public network address is used for connection, set this parameter to Public Network Address. If a private network address is used for connection, set this parameter to Private Network Address.
   • Database_user: Enter the username of the cluster's database. If you use the client to connect to the cluster for the first time, set this parameter to the default administrator configured during cluster creation, for example, dbadmin.
   • Database_port: Enter the database port set during cluster creation.

   For example, run the following command to connect to the default database gaussdb in the GaussDB(DWS) cluster:

   1	gsql -d gaussdb -h 10.168.0.74 -U dbadmin -p 8000 -W password -r

   If the following information is displayed, the connection succeeded:

   1

   gaussdb=>

gsql Command Reference

For more information about the gsql commands, see the Data Warehouse Service (DWS) Tool Guide.