Is it possible to use Liquibase just to check the consistency of the database?
We have several java application modules using the same database. We decided that only one of the modules is responsible for the execution of database migrations, while the other modules (several batch jobs) include the scripts as a dependency. For the batch job modules we want to prevent the migration of the database schema, but we need to be sure that the code base uses the same version as the database.
Is it possible to configure liquibase in a way to perform the validation but not the migration?
We want to try this approach because the migration of two modules starting at the same time caused conflicts that prevented the application from starting.
It's possible to use Liquibase for DB schema validation, however it wasn't quite designed for this.
So, for instance, if you want to always check weather certain table exists or not, you can do the following:
<changeSet author="author_name" id="changeset_id" runAlways="true">
<preConditions onFail="HALT">
<tableExists tableName="foo_bar"/>
</preConditions>
<comment>Table "foo_bar" exists.</comment>
</changeSet>
This changeSet doen't do anything but checking that foo_bar table exists.
runAlways="true" attribute will tell Liquibase to execute the changeSet every time the application starts.
onFail="HALT" will throw an error if foo_bar table doesn't exist, hence if preConditions weren't met.
You can use the liquibase status command to check that all changesets listed in the changelog have been applied, and add the --verbose flag to that to see which changesets have not been applied.
This does not ensure that no drift has happened though - it is certainly possible for someone to manually alter the database and make changes that cause the status command to be inaccurate. As long as you are generally confident that schema changes are always made through liquibase, the status command should be sufficient.
Related
We use liquibase to specify the database layout and the changes of it. In development we use liquibase integrated in our Java application to perform the update if necessary.
Because our application does not have the rights to alter the schema in production, liquibase does not run in production. Instead we use liquibase to generate the SQL scripts. These scripts are then executed manually before our application is deployed.
We would like to make sure that the database layout matches to the changelog that corresponds to the application. The SQL scripts create the DATABASECHANGELOG table and insert the rows like the update command of liquibase would do, so the information about the applied changesets is stored in the database.
However I could not find a suitable liquibase method that only checks if the application's changesets and the database layout/DATABASECHANGELOG are equal. This method must not attempt to fix that, it should only return true/false. Is there such a method available in the liquibase Java API?
After digging through the liquibase source code, I found the method that I was looking for:
liquibase.listUnrunChangeSets(null, null);
This is exactly what I wanted it seems to be working fine.
Is there a way to tell flyway to recreate the flyway-table without applying the migrations. Eg, look into the migration-folder for scripts and assume that they all have been applied and simply make sure that the flyway table contains all of them.
Our scenario is that we are not allowed to run flyway in production and for (ISO;Banking;certifications) reasons. The rules says that we need to remove the tables completely. So when we reset our test-environments from a copy of production we need to recreate the flyway-table. Now we are copy and pasting from an existing test-environment but sometime that isn't in sync with production and all kind of problems occur.
So, we would like to setup our production-copy with the same version as in production and then recreate the tables from that making sure that everything are in sync. But to my understanding the repair-option in flyway doesn't recreate the non-applied scripts...
It looks like what you're describing is called a baseline:
You tell flyway that the database you're working on is at a version number so all scripts previous to this version will be ignored during migrations.
https://flywaydb.org/documentation/commandline/baseline
I have a constraint for my production system that all SQL changes must be executed manually by a DBA for security purposes. Consequently, I want to use Liquibase to generate the SQL, and have the DBA execute it.
However, on application startup in Production, I would like to configure Liquibase to ensure that all changesets have been executed, and have the proper signatures. If either any of the changesets have an invalid signature or have not been executed, I would like Liquibase to throw an exception (which I can then handle in my startup sequence). Under no circumstances would i want Liquibase to update the DB when run in this environment.
In other environments, I would like to leave it to Liquibase to run in default configuration - that is validate that existing changesets have not been modified and execute any missing changesets.
Does Liquibase support this kind of configuration? I've looked through the liquibase.configuration.GlobalConfiguration class, but do not see any config parameters that would provide this config.
You don't specify how you run Liquibase from your application, so it is a bit hard to say exactly. I think you will want to use two different commands - one for production, and one for all other environments. In most environments, you use the update command. In production, you would need to use the status command which returns either a count of the number of undeployed changesets or a list of undeployed changesets.
I have created a Liquibase-CDI addon that supports this functionality. It is based on the liquibase-cdi extension, but uses the CDI observer pattern instead. It can be found on github at https://github.com/benze/liquibase-cdi
We're using liquibase 3.5.1 to help maintain mysql/mariadb installations across dozens of client computers. Our stand-alone app creates a local DB and prepopulates that DB with 'seed' data. With updates to mysql and some other tools we're using, we've been forced to alter some legacy liquibase changesets which obviously changes the checksums for these changesets.
We'd like to have liquibase completely ignore the changes to the checksums.
If it were just a couple of changes or even a lot of changes where a developer could intervene we would just update the databasechangelog table directly. However, there are affected databases on clients' computers who would have no idea how to make the database changes needed.
I know about 'validCheckSum' and thought I could use
--validCheckSum: ANY
in the formatted sql files but that doesn't appear to do anything.
--liquibase formatted sql
--changeset db-scripter:1
--comment: fixing issues with this after upgrading
--validCheckSum: ANY
INSERT INTO ...
'runOnChange' is also not an option as we don't want to rerun any of these old changesets (and insert twice the 'seed' data)
Are we missing any options here? Or perhaps we're not using the validCheckSum correctly?
I had a similar situation, and I solved using clearCheckSums command.
I have a glassfish application which creates its DB schema with liquibase. I have migrated the same application to Spring Boot. I did not drop the DB schema. When I deploy the Spring application and the liquibase scripts run, I get
java.sql.SQLSyntaxErrorException: ORA-00955: name is already used by an existing object
when executing the changeset for creating one of the tables.
I need to specify there is no change in the liquibase scripts and the database changelog lock is acquired successfully.
Shouldn't it skip all the table creation steps? I plug in the same application to the same DB. Have you encountered this situation before?
UPDATE: is it possible that this might be related to the MD5 sum stored in the changelog file ? So the md5 computed by the new application doesn't match the one computed by the old one and the scripts are triggered, causing the obvious exception ?
Many thanks
I don't think you have a checksum difference - that would cause a different error message. What I think is likely is that the DATABASECHANGELOG table has a different changelog path for the changes than what is being reported by Liquibase.
Changesets are identified by 3 things - the changeset id, the author, and the path. When Liquibase is deciding whether a changeset from a changelog should be deployed to a particular database, it looks at the DATABASECHANGELOG table and retrieves that information, compares it with the information in the changelog file, and doeesn't try to deploy anything that matches up. In this case, I think it detects differences in the path and tries to re-deploy the change.