Specifying Where to Load Data From

Each COPY statement requires either a FROM clause to indicate the location of the file or files being loaded or a SOURCE clause when using a user-defined source. For more about the SOURCE clause, see COPY Parameters. This section covers use of the FROM clause.

Loading from a Specific Path

Use the pathToData argument to indicate the location of the file to load. You can load data from the following locations:

  • The local file system.
  • NFS, through a mount point on the local file system.
  • HDFS, using a URL of the form "hdfs:///path/to/data". For more information about HDFS URLs, see HDFS URL Format in Integrating with Apache Hadoop.
  • An S3 or Google Cloud Storage bucket, for data in text, delimited, Parquet, and ORC formats only. See Loading from an S3 Bucket and Loading from Google Cloud Storage.

When copying from the local file system, the COPY statement expects to find files in the same location on every node that participates in the query. If you are using NFS, then you can create an NFS mount point on each node. Doing so allows all database nodes to participate in the load for better performance without requiring files to be copied to all nodes.

Treat NFS mount points as local files in paths:

=> COPY sales FROM '/mount/sales.dat' ON ANY NODE;

You can specify more than one path in the same COPY statement, as in the following example.

=> COPY myTable FROM 'hdfs:///data/sales/01/*.dat', 'hdfs:///data/sales/02/*.dat', 
	'hdfs:///data/sales/historical.dat';

If pathToData resolves to a storage location on a local file system (not HDFS), and the user invoking COPY is not a superuser, these permissions are required:

  • The storage location must have been created with the USER option (see CREATE LOCATION)
  • The user must already have been granted READ access to the storage location where the file or files exist, as described in GRANT (Storage Location)

Vertica prevents symbolic links from allowing unauthorized access.

Loading with Wildcards (glob)

You can invoke COPY for a large number of files in a shared directory with a single statement such as: 

=> COPY myTable FROM '/data/manyfiles/*.dat' ON ANY NODE;

The glob (*) must indicate a set of files, not directories. The following statement fails if /data/manyfiles contains any subdirectories:

=> COPY myTable FROM '/data/manyfiles/*' ON ANY NODE;

Using a wildcard with the ON ANY NODE clause expands the file list on the initiator node. This command then distributes the individual files among all nodes, so that the COPY workload is evenly distributed across the entire cluster.

ON ANY NODE is the default for HDFS paths, as in the following example:

=> COPY myTable FROM 'hdfs:///data/manyfiles/*';

You can also distribute a file set across a subset of nodes, which you might do to balance concurrent loads. For example, this command distributes the loading of individual files among the three named nodes:

=> COPY myTable FROM '/mydirectory/ofmanyfiles/*.dat' 
   ON (v_vmart_node0001, v_vmart_node0002, v_vmart_node0003);

Distributing file loads across nodes depends on two configuration parameters, EnableApportionLoad and EnableApportionFileLoad. Both are enabled by default. See General Parameters for more information about these parameters.

Loading from an S3 Bucket

To access data in S3 you must first do the following tasks:

  • By default, bucket-access is restricted to the communal storage bucket. You should use an AWS access key to load data from non-communal storage buckets.

  • Set the AWSRegion configuration parameter to tell Vertica which AWS region your S3 bucket is in, as in the following example. If the region is not correct, you might experience a delay before the load fails because Vertica retries several times before giving up. The default region is us-east-1.

    => ALTER SESSION SET AWSRegion='us-west-1';

  • To allow users without superuser privileges to access data in S3, create a USER storage location for the S3 path (see CREATE LOCATION) and grant users access, as in the following example:

    => CREATE LOCATION 's3://datalake' SHARED USAGE 'USER' LABEL 's3user';

=> CREATE ROLE ExtUsers;						
   --- Assign users to this role using GRANT (Role).
						
=> GRANT READ ON LOCATION 's3://datalake' TO ExtUsers;

  • If you are using AWS STS temporary session tokens, set the AWSSessionToken parameter as shown in the following example.

    $ aws sts get-session-token 
  { 
    "Credentials": { 
        "AccessKeyId": "ASIAJZQNDVS727EHDHOQ", 
        "SecretAccessKey": "F+xnpkHbst6UPorlLGj/ilJhO5J2n3Yo7Mp4vYvd", 
        "SessionToken": "FQoDYXdzEKv//////////wEaDMWKxakEkCyuDH0UjyKsAe6/3REgW5VbWtpuYyVvSnEK1jzGPHi/jPOPNT7Kd+ftSnD3qdaQ7j28SUW9YYbD50lcXikz/HPlusPuX9sAJJb7w5oiwdg+ZasIS/+ejFgCzLeNE3kDAzLxKKsunvwuo7EhTTyqmlLkLtIWu9zFykzrR+3Tl76X7EUMOaoL31HOYsVEL5d9I9KInF0gE12ZB1yN16MsQVxpSCavOFHQsj/05zbxOQ4o0erY1gU=", 
        "Expiration": "2018-07-18T05:56:33Z" 
    } 
  } 
					
$ vsql
=> ALTER SESSION SET AWSAuth = 'ASIAJZQNDVS727EHDHOQ:F+xnpkHbst6UPorlLGj/ilJhO5J2n3Yo7Mp4vYvd';				
=> ALTER SESSION SET AWSSessionToken = 'FQoDYXdzEKv//////////wEaDMWKxakEkCyuDH0UjyKsAe6/3REgW5VbWtpuYyVvSnEK1jzGPHi/jPOPNT7Kd+ftSnD3qdaQ7j28SUW9YYbD50lcXikz/HPlusPuX9sAJJb7w5oiwdg+ZasIS/+ejFgCzLeNE3kDAzLxKKsunvwuo7EhTTyqmlLkLtIWu9zFykzrR+3Tl76X7EUMOaoL31HOYsVEL5d9I9KInF0gE12ZB1yN16MsQVxpSCavOFHQsj/05zbxOQ4o0erY1gU=';

    If the token expires before your Vertica session ends, you will need to renew it.  Session tokens are best used for short-lived sessions.

You might need to set other S3 Parameters to specify a certificate authority. You can set parameters globally and for the current session with ALTER DATABASE…SET PARAMETER and ALTER SESSION…SET PARAMETER, respectively.

If you use session tokens, all AWS parameters must be set at the session level.

You can then load data from S3 as in the following example.

=> COPY t FROM 's3://datalake/sales.parquet' PARQUET;

You can specify either a path, as in the previous example, or a glob, if all files in the glob can be loaded together. In the following example, AWS_DataLake contains only ORC files.

=> COPY t FROM 's3://datalake/*' ORC;

You can specify a list of comma-separated S3 buckets as in the following example. All buckets must be in the same region. To load from more than one region, use separate COPY statements and change the value of AWSRegion between calls.

=> COPY t FROM 's3://AWS_Data_1/sales.parquet', 's3://AWS_Data_2/sales.parquet' PARQUET;

Parquet files can be partitioned, and Vertica can use partitioning information to improve query performance. See Using Partition Columns for more information.

Loading from Google Cloud Storage

To access data in Google Cloud Storage (GCS) you must first do the following tasks:

  • Create a default project, obtain a developer key, and enable S3 interoperability mode as described in the GCS documentation.

  • Set the GCSAuth configuration parameter as in the following example.

    => ALTER SESSION SET GCSAuth='id:secret';

When reading from GCS you do not need to specify a region.

You might need to set other Google Cloud Storage Parameters. You can set parameters globally and for the current session with ALTER DATABASE…SET PARAMETER and ALTER SESSION…SET PARAMETER, respectively.

If you use session tokens, all GCS parameters must be set at the session level.

You can then access data from GCS as in the following example.

=> COPY t FROM 'gs://DataLake/clicks.parquet' PARQUET;

You can load from more than one bucket in the same COPY statement.

Loading from a Vertica Client

Use COPY LOCAL to load files on a client system to the Vertica database. For example, to copy a GZIP file from your local client, use a command such as this:

=> COPY store.store_dimension FROM LOCAL '/usr/files/my_data/input_file' GZIP;

You can use a comma-separated list to load multiple files of the same compression type. COPY LOCAL then concatenates the files into a single file, so you cannot combine files with different compression types in the list. When listing multiple files, be sure to specify the type of every input file, such as BZIP, as shown: 

=>COPY simple_table FROM LOCAL 'input_file.bz' BZIP, 'input_file.bz' BZIP;

You can load data from a local client from STDIN, as follows: 

=> COPY simple_table FROM LOCAL STDIN;

Loading from Kafka or Spark

For information about streaming data from Kafka, see Integrating with Apache Kafka .

For information about using Vertica with Spark data, see Integrating with Apache Spark.

Loading Data from an IDOL CFS Client

The IDOL Connector Framework Server (CFS) VerticaIndexer feature lets CFS clients connect to your Vertica database using ODBC. After it is connected, CFS uses COPY...FROM LOCAL statements to load IDOL document metadata into an existing flex table. For more information, see the Using Flex Tables for IDOL Data section in Using Flex Tables.