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Loading data into an Amazon Aurora MySQL DB cluster from text files in an Amazon S3 bucket

01 Mar.,2024

 

Loading data into an Amazon Aurora MySQL DB cluster from text files in an Amazon S3 bucket

You can use the LOAD DATA FROM S3 or LOAD XML FROM S3 statement to load data from files stored in an Amazon S3 bucket.

Note

Loading data into a table from text files isn't supported for Aurora Serverless v1. It is supported for Aurora Serverless v2.

Giving Aurora access to Amazon S3

Before you can load data from an Amazon S3 bucket, you must first give your Aurora MySQL DB cluster permission to access Amazon S3.

Granting privileges to load data in Amazon Aurora MySQL

The database user that issues the LOAD DATA FROM S3 or LOAD XML FROM S3 statement must have a specific role or privilege to issue either statement. In Aurora MySQL version 3, you grant the AWS_LOAD_S3_ACCESS role. In Aurora MySQL version 2, you grant the LOAD FROM S3 privilege. The administrative user for a DB cluster is granted the appropriate role or privilege by default. You can grant the privilege to another user by using one of the following statements.

Use the following statement for Aurora MySQL version 3: 

GRANT AWS_LOAD_S3_ACCESS TO 'user'@'domain-or-ip-address'

Tip

When you use the role technique in Aurora MySQL version 3, you can also activate the role by using the SET ROLE role_name or SET ROLE ALL statement. If you aren't familiar with the MySQL 8.0 role system, you can learn more in Role-based privilege model. And for more details, see Using roles in the MySQL Reference Manual.

This only applies to the current active session. When you reconnect, you have to run the SET ROLE statement again to grant privileges. For more information, see SET ROLE statement in the MySQL Reference Manual.

You can use the activate_all_roles_on_login DB cluster parameter to automatically activate all roles when a user connects to a DB instance. When this parameter is set, you don't have to call the SET ROLE statement explicitly to activate a role. For more information, see activate_all_roles_on_login in the MySQL Reference Manual.

Use the following statement for Aurora MySQL version 2:

GRANT LOAD FROM S3 ON *.* TO 'user'@'domain-or-ip-address'

The AWS_LOAD_S3_ACCESS role and LOAD FROM S3 privilege are specific to Amazon Aurora and are not available for external MySQL databases or RDS for MySQL DB instances. If you have set up replication between an Aurora DB cluster as the replication master and a MySQL database as the replication client, then the GRANT statement for the role or privilege causes replication to stop with an error. You can safely skip the error to resume replication. To skip the error on an RDS for MySQL instance, use the mysql_rds_skip_repl_error procedure. To skip the error on an external MySQL database, use the slave_skip_errors system variable (Aurora MySQL version 2) or replica_skip_errors system variable (Aurora MySQL version 3).

Specifying the path (URI) to an Amazon S3 bucket

The syntax for specifying the path (URI) to files stored on an Amazon S3 bucket is as follows.

s3-region://bucket-name/file-name-or-prefix

The path includes the following values:

  • region (optional) – The AWS Region that contains the Amazon S3 bucket to load from. This value is optional. If you don't specify a region value, then Aurora loads your file from Amazon S3 in the same region as your DB cluster.

  • bucket-name – The name of the Amazon S3 bucket that contains the data to load. Object prefixes that identify a virtual folder path are supported.

  • file-name-or-prefix – The name of the Amazon S3 text file or XML file, or a prefix that identifies one or more text or XML files to load. You can also specify a manifest file that identifies one or more text files to load. For more information about using a manifest file to load text files from Amazon S3, see Using a manifest to specify data files to load.

To copy the URI for files in an S3 bucket

  1. Sign in to the AWS Management Console and open the Amazon S3 console at https://console.aws.amazon.com/s3/.

  2. In the navigation pane, choose Buckets, and then choose the bucket whose URI you want to copy.

  3. Select the prefix or file that you want to load from S3.

  4. Choose Copy S3 URI.

LOAD DATA FROM S3

You can use the LOAD DATA FROM S3 statement to load data from any text file format that is supported by the MySQL LOAD DATA INFILE statement, such as text data that is comma-delimited. Compressed files are not supported.

Note

Make sure that your Aurora MySQL DB cluster allows outbound connections to S3. For more information, see Enabling network communication from Amazon Aurora MySQL to other AWS services.

Syntax

LOAD DATA [FROM] S3 [FILE | PREFIX | MANIFEST] 'S3-URI'
    [REPLACE | IGNORE]
    INTO TABLE tbl_name
    [PARTITION (partition_name,...)]
    [CHARACTER SET charset_name]
    [
{
FIELDS | COLUMNS}
        [TERMINATED BY 'string']
        [[OPTIONALLY] ENCLOSED BY 'char']
        [ESCAPED BY 'char']
    ]
    [LINES
        [STARTING BY 'string']
        [TERMINATED BY 'string']
    ]
    [IGNORE number 
{
LINES | ROWS}]
    [(col_name_or_user_var,...)]
    [SET col_name = expr,...]

Note

In Aurora MySQL version 3.05 and higher, the keyword FROM is optional.

Parameters

The LOAD DATA FROM S3 statement uses the following required and optional parameters. You can find more details about some of these parameters in LOAD DATA Statement in the MySQL documentation.

FILE | PREFIX | MANIFEST

Identifies whether to load the data from a single file, from all files that match a given prefix, or from all files in a specified manifest. FILE is the default.

S3-URI

Specifies the URI for a text or manifest file to load, or an Amazon S3 prefix to use. Specify the URI using the syntax described in Specifying the path (URI) to an Amazon S3 bucket.

REPLACE | IGNORE

Determines what action to take if an input row has the same unique key values as an existing row in the database table.

  • Specify REPLACE if you want the input row to replace the existing row in the table.

  • Specify IGNORE if you want to discard the input row.

INTO TABLE

Identifies the name of the database table to load the input rows into.

PARTITION

Requires that all input rows be inserted into the partitions identified by the specified list of comma-separated partition names. If an input row cannot be inserted into one of the specified partitions, then the statement fails and an error is returned.

CHARACTER SET

Identifies the character set of the data in the input file.

FIELDS | COLUMNS

Identifies how the fields or columns in the input file are delimited. Fields are tab-delimited by default.

LINES

Identifies how the lines in the input file are delimited. Lines are delimited by a newline character ('\n') by default.

IGNORE number LINES | ROWS

Specifies to ignore a certain number of lines or rows at the start of the input file. For example, you can use IGNORE 1 LINES to skip over an initial header line containing column names, or IGNORE 2 ROWS to skip over the first two rows of data in the input file. If you also use PREFIX, IGNORE skips a certain number of lines or rows at the start of the first input file.

col_name_or_user_var, ...

Specifies a comma-separated list of one or more column names or user variables that identify which columns to load by name. The name of a user variable used for this purpose must match the name of an element from the text file, prefixed with @. You can employ user variables to store the corresponding field values for subsequent reuse.

For example, the following statement loads the first column from the input file into the first column of table1, and sets the value of the table_column2 column in table1 to the input value of the second column divided by 100.

LOAD DATA FROM S3 's3://mybucket/data.txt'
    INTO TABLE table1
    (column1, @var1)
    SET table_column2 = @var1/100;

SET

Specifies a comma-separated list of assignment operations that set the values of columns in the table to values not included in the input file.

For example, the following statement sets the first two columns of table1 to the values in the first two columns from the input file, and then sets the value of the column3 in table1 to the current time stamp.

LOAD DATA FROM S3  's3://mybucket/data.txt'
    INTO TABLE table1
    (column1, column2)
    SET column3 = CURRENT_TIMESTAMP;

You can use subqueries in the right side of SET assignments. For a subquery that returns a value to be assigned to a column, you can use only a scalar subquery. Also, you cannot use a subquery to select from the table that is being loaded.

You can't use the LOCAL keyword of the LOAD DATA FROM S3 statement if you're loading data from an Amazon S3 bucket.

Using a manifest to specify data files to load

You can use the LOAD DATA FROM S3 statement with the MANIFEST keyword to specify a manifest file in JSON format that lists the text files to be loaded into a table in your DB cluster.

The following JSON schema describes the format and content of a manifest file.

{

    "$schema": "http://json-schema.org/draft-04/schema#",
    "additionalProperties": false,
    "definitions": 
{
},
    "id": "Aurora_LoadFromS3_Manifest",
    "properties": 
{

        "entries": 
{

            "additionalItems": false,
            "id": "/properties/entries",
            "items": 
{

                "additionalProperties": false,
                "id": "/properties/entries/items",
                "properties": 
{

                    "mandatory": 
{

                        "default": "false",
                        "id": "/properties/entries/items/properties/mandatory",
                        "type": "boolean"
                    },
                    "url": 
{

                        "id": "/properties/entries/items/properties/url",
                        "maxLength": 1024,
                        "minLength": 1,
                        "type": "string"
                    }
                },
                "required": [
                    "url"
                ],
                "type": "object"
            },
            "type": "array",
            "uniqueItems": true
        }
    },
    "required": [
        "entries"
    ],
    "type": "object"
}

Each url in the manifest must specify a URL with the bucket name and full object path for the file, not just a prefix. You can use a manifest to load files from different buckets, different regions, or files that do not share the same prefix. If a region is not specified in the URL, the region of the target Aurora DB cluster is used. The following example shows a manifest file that loads four files from different buckets.

{

  "entries": [
    
{

      "url":"s3://aurora-bucket/2013-10-04-customerdata", 
      "mandatory":true
    },
    
{

      "url":"s3-us-west-2://aurora-bucket-usw2/2013-10-05-customerdata",
      "mandatory":true
    },
    
{

      "url":"s3://aurora-bucket/2013-10-04-customerdata", 
      "mandatory":false
    },
    
{

      "url":"s3://aurora-bucket/2013-10-05-customerdata"
    }
  ]
}

The optional mandatory flag specifies whether LOAD DATA FROM S3 should return an error if the file is not found. The mandatory flag defaults to false. Regardless of how mandatory is set, LOAD DATA FROM S3 terminates if no files are found.

Manifest files can have any extension. The following example runs the LOAD DATA FROM S3 statement with the manifest in the previous example, which is named customer.manifest. 

LOAD DATA FROM S3 MANIFEST 's3-us-west-2://aurora-bucket/customer.manifest'
    INTO TABLE CUSTOMER
    FIELDS TERMINATED BY ','
    LINES TERMINATED BY '\n'
    (ID, FIRSTNAME, LASTNAME, EMAIL);

After the statement completes, an entry for each successfully loaded file is written to the aurora_s3_load_history table.

Verifying loaded files using the aurora_s3_load_history table

Every successful LOAD DATA FROM S3 statement updates the aurora_s3_load_history table in the mysql schema with an entry for each file that was loaded.

After you run the LOAD DATA FROM S3 statement, you can verify which files were loaded by querying the aurora_s3_load_history table. To see the files that were loaded from one iteration of the statement, use the WHERE clause to filter the records on the Amazon S3 URI for the manifest file used in the statement. If you have used the same manifest file before, filter the results using the timestamp field.

select * from mysql.aurora_s3_load_history where load_prefix = 'S3_URI';

The following table describes the fields in the aurora_s3_load_history table.

Field Description

load_prefix

The URI that was specified in the load statement. This URI can map to any of the following:

  • A single data file for a LOAD DATA FROM S3 FILE statement

  • An Amazon S3 prefix that maps to multiple data files for a LOAD DATA FROM S3 PREFIX statement

  • A single manifest file that contains the names of files to be loaded for a LOAD DATA FROM S3 MANIFEST statement

file_name

The name of a file that was loaded into Aurora from Amazon S3 using the URI identified in the load_prefix field.

version_number

The version number of the file identified by the file_name field that was loaded, if the Amazon S3 bucket has a version number.

bytes_loaded

The size of the file loaded, in bytes.

load_timestamp

The timestamp when the LOAD DATA FROM S3 statement completed.

Examples

The following statement loads data from an Amazon S3 bucket that is in the same region as the Aurora DB cluster. The statement reads the comma-delimited data in the file customerdata.txt that is in the dbbucket Amazon S3 bucket, and then loads the data into the table store-schema.customer-table.

LOAD DATA FROM S3 's3://dbbucket/customerdata.csv' 
    INTO TABLE store-schema.customer-table
    FIELDS TERMINATED BY ','
    LINES TERMINATED BY '\n'
    (ID, FIRSTNAME, LASTNAME, ADDRESS, EMAIL, PHONE);

The following statement loads data from an Amazon S3 bucket that is in a different region from the Aurora DB cluster. The statement reads the comma-delimited data from all files that match the employee-data object prefix in the my-data Amazon S3 bucket in the us-west-2 region, and then loads the data into the employees table.

LOAD DATA FROM S3 PREFIX 's3-us-west-2://my-data/employee_data'
    INTO TABLE employees
    FIELDS TERMINATED BY ','
    LINES TERMINATED BY '\n'
    (ID, FIRSTNAME, LASTNAME, EMAIL, SALARY);

The following statement loads data from the files specified in a JSON manifest file named q1_sales.json into the sales table. 

LOAD DATA FROM S3 MANIFEST 's3-us-west-2://aurora-bucket/q1_sales.json'
    INTO TABLE sales
    FIELDS TERMINATED BY ','
    LINES TERMINATED BY '\n'
    (MONTH, STORE, GROSS, NET);

LOAD XML FROM S3

You can use the LOAD XML FROM S3 statement to load data from XML files stored on an Amazon S3 bucket in one of three different XML formats:

  • Column names as attributes of a <row> element. The attribute value identifies the contents of the table field.

    <row column1="value1" column2="value2" .../>

  • Column names as child elements of a <row> element. The value of the child element identifies the contents of the table field.

    <row>
  <column1>value1</column1>
  <column2>value2</column2>
</row>

  • Column names in the name attribute of <field> elements in a <row> element. The value of the <field> element identifies the contents of the table field. 

    <row>
  <field name='column1'>value1</field>
  <field name='column2'>value2</field>
</row>

Syntax

LOAD XML FROM S3 'S3-URI'
    [REPLACE | IGNORE]
    INTO TABLE tbl_name
    [PARTITION (partition_name,...)]
    [CHARACTER SET charset_name]
    [ROWS IDENTIFIED BY '<element-name>']
    [IGNORE number 
{
LINES | ROWS}]
    [(field_name_or_user_var,...)]
    [SET col_name = expr,...]

Parameters

The LOAD XML FROM S3 statement uses the following required and optional parameters. You can find more details about some of these parameters in LOAD XML Statement in the MySQL documentation.

FILE | PREFIX

Identifies whether to load the data from a single file, or from all files that match a given prefix. FILE is the default.

REPLACE | IGNORE

Determines what action to take if an input row has the same unique key values as an existing row in the database table.

  • Specify REPLACE if you want the input row to replace the existing row in the table.

  • Specify IGNORE if you want to discard the input row. IGNORE is the default.

INTO TABLE

Identifies the name of the database table to load the input rows into.

PARTITION

Requires that all input rows be inserted into the partitions identified by the specified list of comma-separated partition names. If an input row cannot be inserted into one of the specified partitions, then the statement fails and an error is returned.

CHARACTER SET

Identifies the character set of the data in the input file.

ROWS IDENTIFIED BY

Identifies the element name that identifies a row in the input file. The default is <row>.

IGNORE number LINES | ROWS

Specifies to ignore a certain number of lines or rows at the start of the input file. For example, you can use IGNORE 1 LINES to skip over the first line in the text file, or IGNORE 2 ROWS to skip over the first two rows of data in the input XML.

field_name_or_user_var, ...

Specifies a comma-separated list of one or more XML element names or user variables that identify which elements to load by name. The name of a user variable used for this purpose must match the name of an element from the XML file, prefixed with @. You can employ user variables to store the corresponding field values for subsequent reuse.

For example, the following statement loads the first column from the input file into the first column of table1, and sets the value of the table_column2 column in table1 to the input value of the second column divided by 100.

LOAD XML FROM S3 's3://mybucket/data.xml'
   INTO TABLE table1
   (column1, @var1)
   SET table_column2 = @var1/100;

SET

Specifies a comma-separated list of assignment operations that set the values of columns in the table to values not included in the input file.

For example, the following statement sets the first two columns of table1 to the values in the first two columns from the input file, and then sets the value of the column3 in table1 to the current time stamp.

LOAD XML FROM S3 's3://mybucket/data.xml'
   INTO TABLE table1
   (column1, column2)
   SET column3 = CURRENT_TIMESTAMP;

You can use subqueries in the right side of SET assignments. For a subquery that returns a value to be assigned to a column, you can use only a scalar subquery. Also, you can't use a subquery to select from the table that's being loaded.

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