Importing a PostgreSQL database from an Amazon EC2 instance Using the \copy command to import data to a table on a PostgreSQL DB instance Importing S3 data into RDS for PostgreSQL Transporting PostgreSQL databases between DB instances

Importing data into PostgreSQL on Amazon RDS

Suppose that you have an existing PostgreSQL deployment that you want to move to Amazon RDS. The complexity of your task depends on the size of your database and the types of database objects that you're transferring. For example, consider a database that contains datasets on the order of gigabytes, along with stored procedures and triggers. Such a database is going to be more complicated than a simple database with only a few megabytes of test data and no triggers or stored procedures.

We recommend that you use native PostgreSQL database migration tools under the following conditions:

You have a homogeneous migration, where you are migrating from a database with the same database engine as the target database.
You are migrating an entire database.
The native tools allow you to migrate your system with minimal downtime.

In most other cases, performing a database migration using AWS Database Migration Service (AWS DMS) is the best approach. AWS DMS can migrate databases without downtime and, for many database engines, continue ongoing replication until you are ready to switch over to the target database. You can migrate to either the same database engine or a different database engine using AWS DMS. If you are migrating to a different database engine than your source database, you can use the AWS Schema Conversion Tool (AWS SCT). You use AWS SCT to migrate schema objects that are not migrated by AWS DMS. For more information about AWS DMS, see What is AWS Database Migration Service?

Modify your DB parameter group to include the following settings for your import only. You should test the parameter settings to find the most efficient settings for your DB instance size. You also need to revert back to production values for these parameters after your import completes.

Modify your DB instance settings to the following:

Disable DB instance backups (set backup_retention to 0).
Disable Multi-AZ.

Modify your DB parameter group to include the following settings. You should only use these settings when importing data. You should test the parameter settings to find the most efficient settings for your DB instance size. You also need to revert back to production values for these parameters after your import completes.

Parameter	Recommended value when importing	Description
`maintenance_work_mem`	524288, 1048576, 2097152 or 4194304 (in KB). These settings are comparable to 512 MB, 1 GB, 2 GB, and 4 GB.	The value for this setting depends on the size of your host. This parameter is used during CREATE INDEX statements and each parallel command can use this much memory. Calculate the best value so that you don't set this value so high that you run out of memory.
`checkpoint_segments`	256	The value for this setting consumes more disk space, but gives you less contention on a write ahead log (WAL). For PostgreSQL versions 9.5.x and 9.6.x, this value is `max_wal_size`.
`checkpoint_timeout`	1800	The value for this setting allows for less frequent WAL rotation.
`synchronous_commit`	Off	Disable this setting to speed up writes. Turning this parameter off can increase the risk of data loss in the event of a server crash (do not turn off FSYNC).
`wal_buffers`	8192	This is value is in 8 KB units. This again helps your WAL generation speed
`autovacuum`	Off	Disable the PostgreSQL auto vacuum parameter while you are loading data so that it doesn't use resources

Use the pg_dump -Fc (compressed) or pg_restore -j (parallel) commands with these settings.

Note

The PostgreSQL command pg_dumpall requires super_user permissions that are not granted when you create a DB instance, so it cannot be used for importing data.

Topics

Importing a PostgreSQL database from an Amazon EC2 instance
Using the \copy command to import data to a table on a PostgreSQL DB instance
Importing Amazon S3 data into an RDS for PostgreSQL DB instance
Transporting PostgreSQL databases between DB instances

Importing a PostgreSQL database from an Amazon EC2 instance

If you have data in a PostgreSQL server on an Amazon EC2 instance and want to move it to a PostgreSQL DB instance, you can use the following process. The following list shows the steps to take. Each step is discussed in more detail in the following sections.

Create a file using pg_dump that contains the data to be loaded
Create the target DB instance
Use psql to create the database on the DB instance and load the data
Create a DB snapshot of the DB instance

Step 1: Create a file using pg_dump that contains the data to load

The pg_dump utility uses the COPY command to create a schema and data dump of a PostgreSQL database. The dump script generated by pg_dump loads data into a database with the same name and recreates the tables, indexes, and foreign keys. You can use the pg_restore command and the -d parameter to restore the data to a database with a different name.

Before you create the data dump, you should query the tables to be dumped to get a row count so you can confirm the count on the target DB instance.

The following command creates a dump file called mydb2dump.sql for a database called mydb2.


prompt>pg_dump dbname=mydb2 -f mydb2dump.sql

Step 2: Create the target DB instance

Create the target PostgreSQL DB instance using either the Amazon RDS console, AWS CLI, or API. Create the instance with the backup retention setting set to 0 and disable Multi-AZ. Doing so allows faster data import. You must create a database on the instance before you can dump the data. The database can have the same name as the database that is contained the dumped data. Alternatively, you can create a database with a different name. In this case, you use the pg_restore command and the -d parameter to restore the data into the newly named database.

For example, the following commands can be used to dump, restore, and rename a database.


pg_dump -Fc -v -h [endpoint of instance] -U [master username] [database] > [database].dump
createdb [new database name]
pg_restore -v -h [endpoint of instance] -U [master username] -d [new database name] [database].dump

Step 3: Use psql to create the database on the DB instance and load data

You can use the same connection you used to run the pg_dump command to connect to the target DB instance and recreate the database. Using psql, you can use the master user name and master password to create the database on the DB instance

The following example uses psql and a dump file named mydb2dump.sql to create a database called mydb2 on a PostgreSQL DB instance called mypginstance:

For Linux, macOS, or Unix:


psql \
   -f mydb2dump.sql \
   --host mypginstance.c6c8mntzhgv0.us-west-2.rds.amazonaws.com \
   --port 8199 \
   --username myawsuser \
   --password password \
   --dbname mydb2

For Windows:


psql ^
   -f mydb2dump.sql ^
   --host mypginstance.c6c8mntzhgv0.us-west-2.rds.amazonaws.com ^
   --port 8199 ^
   --username myawsuser ^
   --password password ^
   --dbname mydb2

Step 4: Create a DB snapshot of the DB instance

Once you have verified that the data was loaded into your DB instance, we recommend that you create a DB snapshot of the target PostgreSQL DB instance. DB snapshots are complete backups of your DB instance that can be used to restore your DB instance to a known state. A DB snapshot taken immediately after the load protects you from having to load the data again in case of a mishap. You can also use such a snapshot to seed new DB instances. For information about creating a DB snapshot, see Creating a DB snapshot.

Using the \copy command to import data to a table on a PostgreSQL DB instance

You can run the \copy command from the psql prompt to import data into a table on a PostgreSQL DB instance. The table must already exist on the DB instance. For more information on the \copy command, see the PostgreSQL documentation.

Note

The \copy command doesn't provide confirmation of actions, such as a count of rows inserted. PostgreSQL does provide error messages if the copy command fails due to an error.

Create a .csv file from the data in the source table, log on to the target database on the PostgreSQL instance using psql, and then run the following command. This example uses source-table as the source table name, source-table.csv as the .csv file, and target-db as the target database:


target-db=> \copy source-table from 'source-table.csv' with DELIMITER ',';

You can also run the following command from your client computer command prompt. This example uses source-table as the source table name, source-table.csv as the .csv file, and target-db as the target database:

For Linux, macOS, or Unix:


$psql target-db \
    -U <admin user> \
    -p <port> \
    -h <DB instance name> \
    -c "\copy source-table from 'source-table.csv' with DELIMITER ','"

For Windows:


$psql target-db ^
    -U <admin user> ^
    -p <port> ^
    -h <DB instance name> ^
    -c "\copy source-table from 'source-table.csv' with DELIMITER ','"

Importing Amazon S3 data into an RDS for PostgreSQL DB instance

You can import data from Amazon S3 into a table belonging to an RDS for PostgreSQL DB instance. To do this, you use the aws_s3 PostgreSQL extension that Amazon RDS provides.

Note

To import from Amazon S3 into RDS for PostgreSQL, your database must be running PostgreSQL version 10.7 or later.

For more information on storing data with Amazon S3, see Create a bucket in the Amazon Simple Storage Service Getting Started Guide. For instructions on how to upload a file to an Amazon S3 bucket, see Add an object to a bucket in the Amazon Simple Storage Service Getting Started Guide.

Topics

Overview of importing Amazon S3 data
Setting up access to an Amazon S3 bucket
Using the aws_s3.table_import_from_s3 function to import Amazon S3 data
Function reference

Overview of importing Amazon S3 data

To import data stored in an Amazon S3 bucket to a PostgreSQL database table, follow these steps.

To import S3 data into Amazon RDS

Install the required PostgreSQL extensions. These include the aws_s3 and aws_commons extensions. To do so, start psql and use the following command.
```
psql=> CREATE EXTENSION aws_s3 CASCADE;
NOTICE: installing required extension "aws_commons"
```
The aws_s3 extension provides the aws_s3.table_import_from_s3 function that you use to import Amazon S3 data. The aws_commons extension provides additional helper functions.
Identify the database table and Amazon S3 file to use.

The aws_s3.table_import_from_s3 function requires the name of the PostgreSQL database table that you want to import data into. The function also requires that you identify the Amazon S3 file to import. To provide this information, take the following steps.
1. Identify the PostgreSQL database table to put the data in. For example, the following is a sample t1 database table used in the examples for this topic.
```
psql=> CREATE TABLE t1 (col1 varchar(80), col2 varchar(80), col3 varchar(80));
```
2. Get the following information to identify the Amazon S3 file that you want to import:
  - Bucket name – A bucket is a container for Amazon S3 objects or files.
  - File path – The file path locates the file in the Amazon S3 bucket.
  - AWS Region – The AWS Region is the location of the Amazon S3 bucket. For example, if the S3 bucket is in the US East (N. Virginia) Region, use us-east-1. For a listing of AWS Region names and associated values, see Regions, Availability Zones, and Local Zones .
  To find how to get this information, see View an object in the Amazon Simple Storage Service Getting Started Guide. You can confirm the information by using the AWS CLI command aws s3 cp. If the information is correct, this command downloads a copy of the Amazon S3 file.
```
aws s3 cp s3://sample_s3_bucket/sample_file_path ./ 
```
3. Use the aws_commons.create_s3_uri function to create an aws_commons._s3_uri_1 structure to hold the Amazon S3 file information. You provide this aws_commons._s3_uri_1 structure as a parameter in the call to the aws_s3.table_import_from_s3 function.
  
  For a psql example, see the following.
```
psql=> SELECT aws_commons.create_s3_uri(
   'sample_s3_bucket',
   'sample.csv',
   'us-east-1'
) AS s3_uri \gset
```
Provide permission to access the Amazon S3 file.

To import data from an Amazon S3 file, give the RDS for PostgreSQL DB instance permission to access the Amazon S3 bucket the file is in. To do this, you use either an AWS Identity and Access Management (IAM) role or security credentials. For more information, see Setting up access to an Amazon S3 bucket.
Import the Amazon S3 data by calling the aws_s3.table_import_from_s3 function.

After you complete the previous preparation tasks, use the aws_s3.table_import_from_s3 function to import the Amazon S3 data. For more information, see Using the aws_s3.table_import_from_s3 function to import Amazon S3 data.

Setting up access to an Amazon S3 bucket

To import data from an Amazon S3 file, give the RDS for PostgreSQL DB instance permission to access the Amazon S3 bucket the file is in. You provide access to an Amazon S3 bucket in one of two ways, as described in the following topics.

Topics

Using an IAM role to access an Amazon S3 bucket
Using security credentials to access an Amazon S3 bucket
Troubleshooting access to Amazon S3

Using an IAM role to access an Amazon S3 bucket

Before you load data from an Amazon S3 file, give your RDS for PostgreSQL DB instance permission to access the Amazon S3 bucket the file is in. This way, you don't have to manage additional credential information or provide it in the aws_s3.table_import_from_s3 function call.

To do this, create an IAM policy that provides access to the Amazon S3 bucket. Create an IAM role and attach the policy to the role. Then assign the IAM role to your DB instance.

To give an RDS for PostgreSQL DB instance access to Amazon S3 through an IAM role

Create an IAM policy.

This policy provides the bucket and object permissions that allow your RDS for PostgreSQL DB instance to access Amazon S3.

Include in the policy the following required actions to allow the transfer of files from an Amazon S3 bucket to Amazon RDS:
- s3:GetObject
- s3:ListBucket
Include in the policy the following resources to identify the Amazon S3 bucket and objects in the bucket. This shows the Amazon Resource Name (ARN) format for accessing Amazon S3.
- arn:aws:s3:::your-s3-bucket
- arn:aws:s3:::your-s3-bucket/*
For more information on creating an IAM policy for Amazon RDS for PostgreSQL, see Creating and using an IAM policy for IAM database access. See also Tutorial: Create and attach your first customer managed policy in the IAM User Guide.

The following AWS CLI command creates an IAM policy named rds-s3-import-policy with these options. It grants access to a bucket named your-s3-bucket.

Note

After you create the policy, note the Amazon Resource Name (ARN) of the policy. You need the ARN for a subsequent step when you attach the policy to an IAM role.
Example
For Linux, macOS, or Unix:
```
aws iam create-policy \
   --policy-name rds-s3-import-policy \
   --policy-document '{
     "Version": "2012-10-17",
     "Statement": [
       {
         "Sid": "s3import",
         "Action": [
           "s3:GetObject",
           "s3:ListBucket"
         ],
         "Effect": "Allow",
         "Resource": [
           "arn:aws:s3:::your-s3-bucket", 
           "arn:aws:s3:::your-s3-bucket/*"
         ] 
       }
     ] 
   }'                     
```
For Windows:
```
aws iam create-policy ^
   --policy-name rds-s3-import-policy ^
   --policy-document '{
     "Version": "2012-10-17",
     "Statement": [
       {
         "Sid": "s3import",
         "Action": [
           "s3:GetObject",
           "s3:ListBucket"
         ], 
         "Effect": "Allow",
         "Resource": [
           "arn:aws:s3:::your-s3-bucket", 
           "arn:aws:s3:::your-s3-bucket/*"
         ] 
       }
     ] 
   }'             
```

Create an IAM role.

You do this so Amazon RDS can assume this IAM role on your behalf to access your Amazon S3 buckets. For more information, see Creating a role to delegate permissions to an IAM user in the IAM User Guide.

The following example shows using the AWS CLI command to create a role named rds-s3-import-role.

Example

For Linux, macOS, or Unix:


aws iam create-role \
   --role-name rds-s3-import-role \
   --assume-role-policy-document '{
     "Version": "2012-10-17",
     "Statement": [
       {
         "Effect": "Allow",
         "Principal": {
            "Service": "rds.amazonaws.com"
          },
         "Action": "sts:AssumeRole"
       }
     ] 
   }'

For Windows:


aws iam create-role ^
   --role-name rds-s3-import-role ^
   --assume-role-policy-document '{
     "Version": "2012-10-17",
     "Statement": [
       {
         "Effect": "Allow",
         "Principal": {
            "Service": "rds.amazonaws.com"
          },
         "Action": "sts:AssumeRole"
       }
     ] 
   }'

Attach the IAM policy that you created to the IAM role that you created.

The following AWS CLI command attaches the policy created earlier to the role named rds-s3-import-role Replace your-policy-arn with the policy ARN that you noted in an earlier step.
Example
For Linux, macOS, or Unix:
```
aws iam attach-role-policy \
   --policy-arn your-policy-arn \
   --role-name rds-s3-import-role                    
```
For Windows:
```
aws iam attach-role-policy ^
   --policy-arn your-policy-arn ^
   --role-name rds-s3-import-role    
```
Add the IAM role to the DB instance.

You do so by using the AWS Management Console or AWS CLI, as described following.

Note

Also, be sure the database you use doesn't have any restrictions noted in Importing Amazon S3 data into an RDS for PostgreSQL DB instance.

To add an IAM role for a PostgreSQL DB instance using the console

Sign in to the AWS Management Console and open the Amazon RDS console at https://console.aws.amazon.com/rds/.
Choose the PostgreSQL DB instance name to display its details.
On the Connectivity & security tab, in the Manage IAM roles section, choose the role to add under Add IAM roles to this instance .
Under Feature, choose s3Import.
Choose Add role.

To add an IAM role for a PostgreSQL DB instance using the CLI

Use the following command to add the role to the PostgreSQL DB instance named my-db-instance. Replace your-role-arn with the role ARN that you noted in a previous step. Use s3Import for the value of the --feature-name option.
Example
For Linux, macOS, or Unix:
```
aws rds add-role-to-db-instance \
   --db-instance-identifier my-db-instance \
   --feature-name s3Import \
   --role-arn your-role-arn   \
   --region your-region
```
For Windows:
```
aws rds add-role-to-db-instance ^
   --db-instance-identifier my-db-instance ^
   --feature-name s3Import ^
   --role-arn your-role-arn ^
   --region your-region     
```

Using security credentials to access an Amazon S3 bucket

If you prefer, you can use security credentials to provide access to an Amazon S3 bucket instead of providing access with an IAM role. To do this, use the credentials parameter in the aws_s3.table_import_from_s3 function call.

The credentials parameter is a structure of type aws_commons._aws_credentials_1, which contains AWS credentials. Use the aws_commons.create_aws_credentials function to set the access key and secret key in an aws_commons._aws_credentials_1 structure, as shown following.


psql=> SELECT aws_commons.create_aws_credentials(
   'sample_access_key', 'sample_secret_key', '')
AS creds \gset

After creating the aws_commons._aws_credentials_1 structure, use the aws_s3.table_import_from_s3 function with the credentials parameter to import the data, as shown following.


psql=> SELECT aws_s3.table_import_from_s3(
   't', '', '(format csv)',
   :'s3_uri', 
   :'creds'
);

Or you can include the aws_commons.create_aws_credentials function call inline within the aws_s3.table_import_from_s3 function call.


psql=> SELECT aws_s3.table_import_from_s3(
   't', '', '(format csv)',
   :'s3_uri', 
   aws_commons.create_aws_credentials('sample_access_key', 'sample_secret_key', '')
);

Troubleshooting access to Amazon S3

If you encounter connection problems when attempting to import Amazon S3 file data, see the following for recommendations:

Using the aws_s3.table_import_from_s3 function to import Amazon S3 data

Import your Amazon S3 data by calling the aws_s3.table_import_from_s3 function.

Note

The following examples use the IAM role method for providing access to the Amazon S3 bucket. Thus, there are no credential parameters in the aws_s3.table_import_from_s3 function calls.

The following shows a typical PostgreSQL example using psql.


psql=> SELECT aws_s3.table_import_from_s3(
   't1',
   '', 
   '(format csv)',
   :'s3_uri'
);

The parameters are the following:

t1 – The name for the table in the PostgreSQL DB instance to copy the data into.
'' – An optional list of columns in the database table. You can use this parameter to indicate which columns of the S3 data go in which table columns. If no columns are specified, all the columns are copied to the table. For an example of using a column list, see Importing an Amazon S3 file that uses a custom delimiter.
(format csv) – PostgreSQL COPY arguments. The copy process uses the arguments and format of the PostgreSQL COPY command. In the preceding example, the COPY command uses the comma-separated value (CSV) file format to copy the data.
s3_uri – A structure that contains the information identifying the Amazon S3 file. For an example of using the aws_commons.create_s3_uri function to create an s3_uri structure, see Overview of importing Amazon S3 data.

For the full reference of this function, see aws_s3.table_import_from_s3.

The following examples show how to specify different kinds of files when importing Amazon S3 data.

Topics

Importing an Amazon S3 file that uses a custom delimiter
Importing an Amazon S3 compressed (gzip) file
Importing an encoded Amazon S3 file

Importing an Amazon S3 file that uses a custom delimiter

The following example shows how to import a file that uses a custom delimiter. It also shows how to control where to put the data in the database table using the column_list parameter of the aws_s3.table_import_from_s3 function.

For this example, assume that the following information is organized into pipe-delimited columns in the Amazon S3 file.


1|foo1|bar1|elephant1
2|foo2|bar2|elephant2
3|foo3|bar3|elephant3
4|foo4|bar4|elephant4
...

To import a file that uses a custom delimiter

Create a table in the database for the imported data.


psql=> CREATE TABLE test (a text, b text, c text, d text, e text);
CREATE TABLE

Use the following form of the aws_s3.table_import_from_s3 function to import data from the Amazon S3 file.

You can include the aws_commons.create_s3_uri function call inline within the aws_s3.table_import_from_s3 function call to specify the file.
```
psql=> SELECT aws_s3.table_import_from_s3(
   'test',
   'a,b,d,e',
   'DELIMITER ''|''', 
   aws_commons.create_s3_uri('sampleBucket', 'pipeDelimitedSampleFile', 'us-east-2')
);
```

The data is now in the table in the following columns.


psql=> SELECT * FROM test;
a | b | c | d | e 
---+------+---+---+------+-----------
1 | foo1 | | bar1 | elephant1
2 | foo2 | | bar2 | elephant2
3 | foo3 | | bar3 | elephant3
4 | foo4 | | bar4 | elephant4

Importing an Amazon S3 compressed (gzip) file

The following example shows how to import a file from Amazon S3 that is compressed with gzip.

Ensure that the file contains the following Amazon S3 metadata:

Key: Content-Encoding
Value: gzip

For more about adding these values to Amazon S3 metadata, see How do I add metadata to an S3 object? in the Amazon Simple Storage Service Console User Guide.

Import the gzip file into your RDS for PostgreSQL DB instance as shown following.


psql=> CREATE TABLE test_gzip(id int, a text, b text, c text, d text);
CREATE TABLE
psql=> SELECT aws_s3.table_import_from_s3(
 'test_gzip', '', '(format csv)',
 'myS3Bucket', 'test-data.gz', 'us-east-2'
);

Importing an encoded Amazon S3 file

The following example shows how to import a file from Amazon S3 that has Windows-1252 encoding.


psql=> SELECT aws_s3.table_import_from_s3(
 'test_table', '', 'encoding ''WIN1252''',
 aws_commons.create_s3_uri('sampleBucket', 'SampleFile', 'us-east-2')
);

Function reference

Functions

aws_s3.table_import_from_s3
aws_commons.create_s3_uri
aws_commons.create_aws_credentials

aws_s3.table_import_from_s3

Imports Amazon S3 data into an Amazon RDS table. The aws_s3 extension provides the aws_s3.table_import_from_s3 function.

Syntax

The three required parameters are table_name, column_list and options. These identify the database table and specify how the data is copied into the table.

You can also use these parameters:

The s3_info parameter specifies the Amazon S3 file to import. When you use this parameter, access to Amazon S3 is provided by an IAM role for the PostgreSQL DB instance.
```
aws_s3.table_import_from_s3 (
   table_name text, 
   column_list text, 
   options text, 
   s3_info aws_commons._s3_uri_1
) 
```
The credentials parameter specifies the credentials to access Amazon S3. When you use this parameter, you don't use an IAM role.
```
aws_s3.table_import_from_s3 (
   table_name text, 
   column_list text, 
   options text, 
   s3_info aws_commons._s3_uri_1,
   credentials aws_commons._aws_credentials_1
)
```

Parameters

table_name

A required text string containing the name of the PostgreSQL database table to import the data into.

column_list

A required text string containing an optional list of the PostgreSQL database table columns in which to copy the data. If the string is empty, all columns of the table are used. For an example, see Importing an Amazon S3 file that uses a custom delimiter.

options

A required text string containing arguments for the PostgreSQL COPY command. These arguments specify how the data is to be copied into the PostgreSQL table. For more details, see the PostgreSQL COPY documentation.

s3_info

An aws_commons._s3_uri_1 composite type containing the following information about the S3 object:

bucket – The name of the Amazon S3 bucket containing the file.
file_path – The Amazon S3 path of the file.
region – The AWS Region that the file is in. For a listing of AWS Region names and associated values, see Regions, Availability Zones, and Local Zones .

credentials

An aws_commons._aws_credentials_1 composite type containing the following credentials to use for the import operation:

Access key
Secret key
Session token

For information about creating an aws_commons._aws_credentials_1 composite structure, see aws_commons.create_aws_credentials.

Alternate syntax

To help with testing, you can use an expanded set of parameters instead of the s3_info and credentials parameters. Following are additional syntax variations for the aws_s3.table_import_from_s3 function:

Instead of using the s3_info parameter to identify an Amazon S3 file, use the combination of the bucket, file_path, and region parameters. With this form of the function, access to Amazon S3 is provided by an IAM role on the PostgreSQL DB instance.
```
aws_s3.table_import_from_s3 (
   table_name text, 
   column_list text, 
   options text, 
   bucket text, 
   file_path text, 
   region text 
)
```

Instead of using the credentials parameter to specify Amazon S3 access, use the combination of the access_key, session_key, and session_token parameters.


aws_s3.table_import_from_s3 (
   table_name text, 
   column_list text, 
   options text, 
   bucket text, 
   file_path text, 
   region text, 
   access_key text, 
   secret_key text, 
   session_token text 
)

Alternate parameters

bucket: A text string containing the name of the Amazon S3 bucket that contains the file.
file_path: A text string containing the Amazon S3 path of the file.
region: A text string containing the AWS Region that the file is in. For a listing of AWS Region names and associated values, see Regions, Availability Zones, and Local Zones .
access_key: A text string containing the access key to use for the import operation. The default is NULL.
secret_key: A text string containing the secret key to use for the import operation. The default is NULL.
session_token: (Optional) A text string containing the session key to use for the import operation. The default is NULL.

aws_commons.create_s3_uri

Creates an aws_commons._s3_uri_1 structure to hold Amazon S3 file information. Use the results of the aws_commons.create_s3_uri function in the s3_info parameter of the aws_s3.table_import_from_s3 function.

Syntax


aws_commons.create_s3_uri(
   bucket text,
   file_path text,
   region text
)

Parameters

bucket: A required text string containing the Amazon S3 bucket name for the file.
file_path: A required text string containing the Amazon S3 path of the file.
region: A required text string containing the AWS Region that the file is in. For a listing of AWS Region names and associated values, see Regions, Availability Zones, and Local Zones .

aws_commons.create_aws_credentials

Sets an access key and secret key in an aws_commons._aws_credentials_1 structure. Use the results of the aws_commons.create_aws_credentials function in the credentials parameter of the aws_s3.table_import_from_s3 function.

Syntax


aws_commons.create_aws_credentials(
   access_key text,
   secret_key text,
   session_token text
)

Parameters

access_key: A required text string containing the access key to use for importing an Amazon S3 file. The default is NULL.
secret_key: A required text string containing the secret key to use for importing an Amazon S3 file. The default is NULL.
session_token: An optional text string containing the session token to use for importing an Amazon S3 file. The default is NULL. If you provide an optional session_token, you can use temporary credentials.

Transporting PostgreSQL databases between DB instances

By using PostgreSQL Transportable Databases for Amazon RDS, you can transport a PostgreSQL database between two DB instances. This provides an extremely fast method of migrating large databases between separate DB instances. To transport databases using this method, your DB instances must both run the same major version of PostgreSQL.

To use transportable databases, install the pg_transport extension. This extension provides a physical transport mechanism to move each database. By streaming the database files with minimal processing, physical transport moves data much faster than traditional dump and load processes and takes minimal downtime. PostgreSQL transportable databases use a pull model where the destination DB instance imports the database from the source DB instance.

Note

PostgreSQL transportable databases are available in RDS for PostgreSQL versions 10.10 and later, and 11.5 and later.

Topics

Limitations for using PostgreSQL transportable databases
Setting up to transport PostgreSQL databases
Transporting a PostgreSQL database using the transport.import_from_server function
What happens during database transport
transport.import_from_server function reference
Configuration parameters for the pg_transport extension

Limitations for using PostgreSQL transportable databases

Transportable databases have the following limitations:

Read replicas – You can't use transportable databases on read replicas or parent instances of read replicas.
Unsupported column types – You can't use the reg data types in any database tables that you plan to transport with this method. These types depend on system catalog object IDs (OIDs), which often change during transport.
Tablespaces – All source database objects must be in the default pg_default tablespace.
Compatibility – Both the source and destination DB instances must run the same major version of PostgreSQL.

Before transport begins, the transport.import_from_server function compares the source and destination DB instances to ensure database compatibility. This includes verifying PostgreSQL major version compatibility. Also, the function verifies that the destination DB instance likely has enough space to receive the source database. The function performs several additional checks to make sure that the transport is smooth.
Extensions – The only extension that you can install on the source DB instance during transport is pg_transport.
Roles and ACLs – The source database's access privileges and ownership information aren't carried over to the destination database. All database objects are created and owned by the local destination user of the transport.
Concurrent transports – You can run up to 32 total transports at the same time on a DB instance, including both imports and exports. To define the worker processes used for each transport, use the pg_transport.work_mem and pg_transport.num_workers parameters. To accommodate concurrent transports, you might need to increase the max_worker_processes parameter quite a bit. For more information, see Configuration parameters for the pg_transport extension.

Setting up to transport PostgreSQL databases

To prepare to transport a PostgreSQL database from one DB instance to another, take the following steps.

To set up for transporting a PostgreSQL database

Make sure that the source DB instance's security group allows inbound traffic from the destination DB instance. This is required because the destination DB instance starts the database transport with an import call to the source DB instance. For information about how to use security groups, see Controlling access with security groups.
For both the source and destination DB instances, add pg_transport to the shared_preload_libraries parameter for each parameter group. The shared_preload_libraries parameter is static and requires a database restart for changes to take effect. For information about parameter groups, see Working with DB parameter groups.
For both the source and destination DB instances, install the required pg_transport PostgreSQL extension.

To do so, start psql as a user with the rds_superuser role for each DB instance, and then run the following command.
```
psql=> CREATE EXTENSION pg_transport;
```

Transporting a PostgreSQL database using the transport.import_from_server function

After you complete the process described in Setting up to transport PostgreSQL databases, you can start the transport. To do so, run the transport.import_from_server function on the destination DB instance.

Note

Both the destination user for transport and the source user for the connection must be members of the rds_superuser role.

The destination DB instance can't already contain a database with the same name as the source database to be transported, or the transport fails.

The following shows an example transport.


SELECT transport.import_from_server( 
   'source-db-instance-endpoint', 
    source-db-instance-port, 
   'source-db-instance-user', 
   'source-user-password', 
   'source-database-name', 
   'destination-user-password', 
   false);

This function requires that you provide database user passwords. Thus, we recommend that you change the passwords of the user roles you used after transport is complete. Or, you can use SQL bind variables to create temporary user roles. Use these temporary roles for the transport and then discard the roles afterwards.

For details of the transport.import_from_server function and its parameters, see transport.import_from_server function reference.

What happens during database transport

The transport.import_from_server function creates the in-transit database on the destination DB instance. The in-transit database is inaccessible on the destination DB instance for the duration of the transport.

When transport begins, all current sessions on the source database are ended. Any databases other than the source database on the source DB instance aren't affected by the transport.

The source database is put into a special read-only mode. While it's in this mode, you can connect to the source database and run read-only queries. However, write-enabled queries and some other types of commands are blocked. Only the specific source database that is being transported is affected by these restrictions.

During transport, you can't restore the destination DB instance to a point in time. This is because the transport isn't transactional and doesn't use the PostgreSQL write-ahead log to record changes. If the destination DB instance has automatic backups enabled, a backup is automatically taken after transport completes. Point-in-time restores are available for times after the backup finishes.

If the transport fails, the pg_transport extension attempts to undo all changes to the source and destination DB instances. This includes removing the destination's partially transported database. Depending on the type of failure, the source database might continue to reject write-enabled queries. If this happens, use the following command to allow write-enabled queries.


ALTER DATABASE my-database SET default_transaction_read_only = false;

transport.import_from_server function reference

The transport.import_from_server function transports a PostgreSQL database by importing it from a source DB instance to a destination DB instance. It does this by using a physical database connection transport mechanism.

Syntax


transport.import_from_server(
   host text,
   port int,
   username text,
   password text,
   database text,
   local_password text,
   dry_run bool
)

Return Value

None.

Parameters

You can find descriptions of the transport.import_from_server function parameters in the following table.

Parameter	Description
`host`	The endpoint of the source DB instance.
`port`	An integer representing the port of the source DB instance. PostgreSQL DB instances often use port 5432.
`username`	The user of the source DB instance. This user must be a member of the `rds_superuser` role.
`password`	The user password of the source DB instance.
`database`	The name of the database in the source DB instance to transport.
`local_password`	The local password of the current user for the destination DB instance. This user must be a member of the `rds_superuser` role.
`dry_run`	An optional Boolean value specifying whether to perform a dry run. The default is `false`, which means the transport proceeds. To confirm compatibility between the source and destination DB instances without performing the actual transport, set `dry_run` to `true`.

Example

For an example, see Transporting a PostgreSQL database using the transport.import_from_server function.

Configuration parameters for the pg_transport extension

Use the following parameters to configure the pg_transport extension behavior.


SET pg_transport.num_workers = integer; 
SET pg_transport.work_mem = kilobytes;
SET pg_transport.timing = Boolean;

You can find descriptions of these parameters in the following table.

Parameter Description

Parameter	Description
`pg_transport.num_workers`	The number of workers to use for a physical transport. The default is 3. Valid values are 1–32. Even large transports typically reach their maximum throughput with fewer than 8 workers. During transport, the `pg_transport.num_workers` setting on the destination DB instance is used on both the destination and source DB instances. A related parameter is the PostgreSQL `max_worker_processes` parameter. The transport process creates several background worker processes. Thus, your setting for the `pg_transport.num_workers` parameter might require you to set the `max_worker_processes` parameter significantly higher on both the source and destination DB instances. We recommend that you set `max_worker_processes` on both the source and destination DB instances to at least three times the destination DB instance's setting for the `pg_transport.num_workers` parameter. Add a few more to provide nontransport background worker processes. For more information about the `max_worker_processes` parameter, see the PostgreSQL documentation about Asynchronous behavior.
`pg_transport.timing`	A Boolean value that specifies whether to report timing information during the transport. The default is `true`. Valid values are `true` to report timing information and `false` to disable the reporting of timing information. We don't recommend that you set this parameter to `false`. Disabling `pg_transport.timing` significantly reduces your ability to track the progress of transports.
`pg_transport.work_mem`	The maximum amount of memory to allocate for each worker. The default is 131,072 kilobytes (KB). The minimum value is 64 megabytes (65,536 KB). Valid values are in kilobytes (KBs) as binary base-2 units, where 1 KB = 1,024 bytes. The transport might use less memory than is specified in this parameter. Even large transports typically reach their maximum throughput with less than 256 MB (262,144 KB) of memory per worker.

pg_transport.num_workers

The number of workers to use for a physical transport. The default is 3. Valid values are 1–32. Even large transports typically reach their maximum throughput with fewer than 8 workers.

During transport, the pg_transport.num_workers setting on the destination DB instance is used on both the destination and source DB instances.

A related parameter is the PostgreSQL max_worker_processes parameter. The transport process creates several background worker processes. Thus, your setting for the pg_transport.num_workers parameter might require you to set the max_worker_processes parameter significantly higher on both the source and destination DB instances.

We recommend that you set max_worker_processes on both the source and destination DB instances to at least three times the destination DB instance's setting for the pg_transport.num_workers parameter. Add a few more to provide nontransport background worker processes.

For more information about the max_worker_processes parameter, see the PostgreSQL documentation about Asynchronous behavior.

pg_transport.timing

A Boolean value that specifies whether to report timing information during the transport. The default is true. Valid values are true to report timing information and false to disable the reporting of timing information.

We don't recommend that you set this parameter to false. Disabling pg_transport.timing significantly reduces your ability to track the progress of transports.

pg_transport.work_mem

The maximum amount of memory to allocate for each worker. The default is 131,072 kilobytes (KB). The minimum value is 64 megabytes (65,536 KB). Valid values are in kilobytes (KBs) as binary base-2 units, where 1 KB = 1,024 bytes.

The transport might use less memory than is specified in this parameter. Even large transports typically reach their maximum throughput with less than 256 MB (262,144 KB) of memory per worker.

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Document Conventions

Working with PostgreSQL read replicas

Exporting PostgreSQL data into Amazon S3 files