Tutorial Error Overrides - Flyway

{% include teams.html %}

This tutorial assumes you have successfully completed the {% include quickstart-maven.html %} tutorial. If you have not done so, please do so first. This tutorial picks up where that one left off.

This brief tutorial will teach how to use Error Overrides. It will take you through the steps on how to configure and use them.

Introduction

Error Overrides are a great fit for situations where you may want to:

treat an error as a warning as you know your migration will handle it correctly later
treat a warning as an error as you prefer to fail fast to be able to fix the problem sooner

Reviewing the status

After having completed the {% include quickstart-maven.html %}, you can now execute

<pre class="console">bar> mvn flyway:info</pre>

This should give you the following status:

Adding a broken migration

In this tutorial we're going to simulate the case where a broken sql statement should be ignored.

So let's start by adding a new migration called src/main/resources/db/migration/V3__Invalid.sql:

sql

broken sql statement;

If we migrate the database using

<pre class="console">bar> mvn flyway:migrate</pre>

it will fail as expected:

<pre class="console">[ERROR] Migration V3__Invalid.sql failed [ERROR] -------------------------------- [ERROR] SQL State : 42001 [ERROR] Error Code : 42001 [ERROR] Message : Syntax error in SQL statement "BROKEN[*] SQL STATEMENT "; expected "BACKUP, BEGIN, {"; SQL statement: [ERROR] broken sql statement [42001-191] [ERROR] Location : /bar/src/main/resources/db/migration/V3__Invalid.sql (/bar/src/main/resources/db/migration/V3__Invalid.sql) [ERROR] Line : 1 [ERROR] Statement : broken sql statement</pre>

Configuring an Error Override

Now let's configure an Error Override that will trap invalid statements in our migrations and simply log a warning instead of failing with an error.

xml

<project xmlns="...">
    ...
    <build>
        <plugins>
            <plugin>
                <groupId>org.flywaydb</groupId>
                <artifactId>flyway-maven-plugin</artifactId>
                <version>{{ site.flywayVersion }}</version>
                <configuration>
                    <url>jdbc:h2:file:./target/foobar</url>
                    <user>sa</user>
                    <errorOverrides>
                        <errorOverride>42001:42001:W</errorOverride>
                    </errorOverrides>
                </configuration>
                <dependencies>
                    <dependency>
                        <groupId>com.h2database</groupId>
                        <artifactId>h2</artifactId>
                        <version>1.4.191</version>
                    </dependency>
                </dependencies>
            </plugin>
        </plugins>
    </build>
</project>

Finally clean and migrate again using

<pre class="console">bar> mvn flyway:clean flyway:migrate</pre>

And we now get:

<pre class="console">[INFO] Database: jdbc:h2:file:./target/foobar (H2 1.4) [INFO] Successfully validated 3 migrations (execution time 00:00.007s) [INFO] Creating Schema History table: "PUBLIC"."flyway_schema_history" [INFO] Current version of schema "PUBLIC": << Empty Schema >> [INFO] Migrating schema "PUBLIC" to version 1 - Create person table [INFO] Migrating schema "PUBLIC" to version 2 - Add people [INFO] Migrating schema "PUBLIC" to version 3 - Invalid [WARNING] Syntax error in SQL statement (SQL state: 42001, error code: 42001) [INFO] Successfully applied 3 migrations to schema "PUBLIC" (execution time 00:00.039s)</pre>

And as we were expecting we now had a successful execution with a warning instead of an error.

Summary

In this brief tutorial we saw how to

configure Flyway to use error overrides