Verify a migration

This page describes how to confirm that your migrated data is complete and accurate. At a minimum, you should run SQL statements to verify that your tables exist in the migrated Cloud SQL database. For a more precise data comparison between the source and destination database, you can try using the open-source Data Validation Tool.

Verify destination data with SQL statements

You can run SQL statements to verify that your tables exist in the migrated Cloud SQL database. Do the following:

Connect to your Cloud SQL for SQL Server instance with a tool where you can run SQL commands against your migrated databases.
For more information on connecting to Cloud SQL instances, see Connection options in Cloud SQL documentation.
Run SQL commands to verify your migrated data. For example:
List all tables in a database

Run the following commands to check if your migrated database contains all the necessary tables:
1. Start using a specific database:
```
USE DATABASE_NAME;
GO
```
2. List all tables in the database:
```
SELECT * FROM information_schema.tables;
```
Check table content and definitions

Run the following commands to verify the correctness of a specific migrated table:
1. Start using a specific database:
```
USE DATABASE_NAME;
GO
```
2. View the table definition:
```
EXEC sp_help 'dbo.TABLE_NAME';
```
3. Verify the table contents:
```
SELECT * FROM TABLE_NAME';
GO
```

Verify data with the Data Validation Tool

The open-source Data Validation Tool lets you perform very precise data comparisons between two databases, but it requires creating network connections to your source and destination databases.

The following steps show a minimal example:

Deploy or use a virtual machine with access to both the source and the destination.
In the virtual machine, create a folder in which to install the Data Validation Tool.
Navigate to this folder.
Use pip to install the Data Validation Tool.
```
pip install google-pso-data-validator
```

Create connections to the source SQL Server database and the destination Cloud SQL database.

data-validation connections add -c SOURCE_CONNECTION_NAME MSSQL --host 'ip-address' --port port --user username --password pswd --database database-name
data-validation connections add -c TARGET_CONNECTION_NAME Postgres --host 'ip-address' --port port --user username --password pswd --database database-name

For example:

data-validation connections add -c source_connection_name MSSQL --host '10.10.10.11' --port 1521 --user system --password pswd --database XE
data-validation connections add -c target_connection_name Postgres --host '10.10.10.12' --port 5432 --user postgres --password pswd --database postgres

Create or generate a list of tables to compare data between the source and destination databases.

export TABLES_LIST=$(data-validation find-tables --source-conn SOURCE_CONNECTION_NAME --target-conn TARGET_CONNECTION_NAME --allowed-schemas schema-name)

For example:

export TABLES_LIST=$(data-validation find-tables --source-conn source_connection_name --target-conn target_connection_name --allowed-schemas public)

Run full validation against all tables.

data-validation validate column --source-conn source_connection_name --target-conn target_connection_name --tables-list "${TABLES_LIST}"

We suggest that you run this validation during replication to ensure relative consistency. Large table queries may take too long to run during a small promotion window. In such cases, use the Data Validation Tool to add filters to reduce runtime or prepare the table list to include a subset of tables for the final validation.

Verify a migration

Verify destination data with SQL statements

List all tables in a database

Check table content and definitions

Verify data with the Data Validation Tool