Profiling Information

For some issues you may be asked by Support to provide profiling information for a problematic query. To get this information you must first run a test of the problematic statement with profiling enabled, and then retrieve the log files for that session.

Step 1: Run a test of the problematic statement with profiling enabled

  1. Open a new database connection using your preferred SQL client.
  2. Copy the problematic SQL query into the following statement and execute it:
    set autocommit on;
      alter session set profile='on';
    //  <insert your query here>;
      alter session set profile='off';
      alter session set NLS_NUMERIC_CHARACTERS='.,';
      alter session set NLS_TIMESTAMP_FORMAT='YYYY-MM-DD HH:MI:SS.ff3';
     
      flush statistics;
     
      export (
        select *
        from EXA_STATISTICS.EXA_USER_PROFILE_LAST_DAY
        where session_id = current_session
      )
      into LOCAL CSV
      FILE 'profile_output.csv';
  3. Attach the generated CSV file profile_output.csv to your support ticket.

Step 2: Get the log files for the test session

In this step, you will request the logs for a specific session.

Make sure you have enough free disk space for the log. For more information, see EXAsupport.

The following examples use the c4 and confd_client command-line tools in a Linux terminal. For more information about these tools, see Exasol Deployment Tool (c4) and ConfD.

  1. Connect to EXAClusterOS (COS) using c4 connect -t <DEPLOYMENT>[.<NODE>]/cos. For example:

    c4 connect -t 1/cos

    In most cases it does not matter on which node you access ConfD. If you do not specify a node, c4 will connect to the first active node in the deployment. The command prompt in COS indicates which node you are connected to: 

    [root@n11 ~]#

    For more information about how to use c4 connect, see How to use c4.

  2. To find the name of the database, use the ConfD job db_list. For example:

    confd_client db_list
    - MY_DATABASE

  3. To collect information about a specific SQL session, use the EXAsupport command-line tool and provide the relevant session ID. Specify the start date (-s) and end date (-t) using the format YYYY-MM-DD.

    You can only collect SQL logs for a specific session on the day that the session occurred.

    For example:

    exasupport -s 2022-08-11 -t 2022-08-11 -e DB_NAME -i SESSION_ID

    If the log file was created successfully, you will see the following message containing the file name:

    Successfully stored debug information into file /exa/tmp/support/exacluster_debuginfo_2022_08_11-23_27_20.tar.gz

  4. To disconnect from EXAClusterOS, use CTRL+D or type exit.

  5. Copy the log file to your local computer using the scp command (secure copy). 

    scp -P $COS_PORT -i ~/.ssh/$KEY root@$DATABASE_IP:/exa/tmp/support/$FILENAME $LOCAL_FOLDER
    Parameter Description
    $COS_PORT

    The SSH port for connecting to EXAClusterOS (COS). Default = 20002

    To find the port number in the configuration, use c4 config | grep CCC_PLAY_SSHD_PORT.
    $KEY

    The filename of the SSH private key.

    To find the filename in the configuration, use c4 config | grep CCC_AWS_KEY_PAIR_FILE.
    $DATABASE_IP

    The external IP address of the cluster node that you were connected to when creating the log file.

    To find the IP addresses of all nodes, use c4 ps.

    $FILENAME The name of the log file that was generated by exasupport in the previous step.
    $LOCAL_FOLDER Path to a folder on your computer where the log file will be stored.

    Example

    Get the necessary info: 

    c4 config | grep CCC_AWS_KEY_PAIR_FILE
    CCC_AWS_KEY_PAIR_FILE=my_private_key.pem

    c4 config | grep CCC_PLAY_SSHD_PORT
    CCC_PLAY_SSHD_PORT=20002

    c4 ps 
          N  PLAY_ID   NODE  MEDIUM  INSTANCE     EXTERNAL_IP     INTERNAL_IP  STAGE  STATE      UPTIME    TTL
      ┌─  1  3a4a7d8d  10    awscf   c5d.large    203.0.113.10    10.0.0.10    c      running    04:35:15  +∞
      │   1  3a4a7d8d  11    awscf   c5d.2xlarge  203.0.113.11    10.0.0.11    d      running    04:35:16  +∞
      └─  1  3a4a7d8d  12    awscf   c5d.2xlarge  203.0.113.12    10.0.0.12    d      running    04:35:15  +∞

    Copy the file to your local machine:

    scp -P 2002 -i ~/.ssh/my_private_key.pem \
      root@203.0.113.10:/exa/tmp/support/exacluster_debuginfo_2022_08_11-23_27_20.tar.gz ~/my_logs/

    Verification

    To verify that the log was successfully copied, use the ls command in the target folder on your local machine.

    Example

    ls -lahtr ~/mylogs | grep exacluster_debuginfo
    -rwxr-xr-x  1 user group 9.8K Sep 20 17:38 exacluster_debuginfo_2022_08_11-23_27_20.tar.gz