We have a production system with a large DB (several hundred tables) and would like to begin using Flyway to manage DDL changes that occur through the dev cycle. However, the organization is setup in such a way that there are production DB changes that sometimes occur, mostly just data changes but possibly DDL, that will happen outside of a data migration tool. While this is obviously an organizational challenge, does this fact alone cripple a tool like Flyway? Or is there a workflow where Flyway could rebuild its indices on demand such that any out-of-band DB change like this is pulled in?
We'd love to use Flyway, but would need to integrate it incrementally until all teams using the system are trained/bought in.
When introducing Flyway to a DB with existing data you will need to baseline Flyway to integrate with your existing data. See baseline.
For changes made after this, Flyway will only track and version changes made from its own migration scripts and not changes made externally to it. However, this does not mean you cannot use the two together, but you would need to be more aware of your database structure to avoid conflicts between your flyway migrations and external changes.
Transactional data changes made to production shouldn't impact Flyway as these won't be versioned.
If you're referring to static data (eg lookup data) that you'd like Flyway to manage, then this isn't detected by Flyway (at least not today). If you discover that you have drift you'll need to add the changes as a new migration script using idempotent syntax to ensure that next time this runs against production it doesn't try to make the same changes again.
For out-of-band schema changes, The enterprise edition of Flyway has a drift check, so at least you'd be made aware of them. However, as for the data changes described above, you'll need to manually add these schema changes as an idempotent migration script.
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We have not used Flyway from the beginning of our project. We are at an advanced state of development. An expert review has suggested to use Flyway in our project.
The problem is that we have moved part of our services (microservices) into another testing environment as well.
What is the best way to properly implement Flyway? The requirements are:
In Development environment, no need to alter the schema which is already existing. But all new scripts should be done using Flyway.
In Testing environment, no need to alter the schema which is already existing. But what is not available in testing environment should be created automatically using Flyway when we do migrate project from Dev to test.
When we do migration to a totally new envrionment (UAT, Production etc) the entire schema should be created automatically using Flyway.
From the documentation, what I understood is:
Take a backup of the development schema (both DDL and DML) as SQL script files, give a file name like V1_0_1__initial.sql.
Clean the development database using "flyway clean".
Baseline the Development database "flyway baseline -baselineversion=1.0.0"
Now, execute "flyway migrate" which will apply the SQL script file V1_0_1__initial.sql.
Any new scripts should be written with higher version numbers (like V2_0_1__account_table.sql)
Is this the correct way or is there any better way to do this?
The problem is that I have a test database where we have different set of data (Data in Dev and test are different and I would like to keep the data as it is in both the environments). If so, is it good to separate the DDL and DML in different script files when we take it from the Dev environment and apply them separately in each environment? The DML can be added manually as required; but bit confused if I am doing the right thing.
Thanks in advance.
So, there are actually two questions here. Data management and Flyway management.
In terms of data management, yes, that should be a separate thing. Data grows and grows. Trying to manage data, beyond simple lookup tables, from source control quickly becomes very problematic. Not to mention that you want different data in different environments. This also makes automating deployments much more difficult (branching would be your friend if you insist on going this route, one branch for each data set, then deploy appropriately).
You can implement Flyway on an existing project, yes. The key is establishing the baseline. You don't have to do all the steps you outlined above. Let's say you have an existing database. You have to get the script that defines that database. That single script should include all appropriate DDL (and, if you want, DML). Name it following the Flyway standards. Something like V1.0__Baseline.sql.
With that in place, all you must do is run:
flyway baseline
That will establish your existing code base as the start point. From there, you just have to create scripts following the naming standard: V1.1xxx V2.0xxx V53000.1xxx. And run
flyway migrate
To deploy appropriate changes.
The only caveat to this is that, as the documentation states, you must ensure that all your databases match this V1.0 that you're creating and marking as the baseline. Any deviation will cause errors as you introduce new changes and migrate them into place. As long as you've got matching baseline points, you should be able to proceed with different data in different environments with no issues.
This is my how-to instruction on integration flyway with prod DB: https://delicious-snipe-938.notion.site/How-to-integrate-Flyway-with-existing-MySQL-DB-in-Prod-PostgreSQL-is-similar-1eabafa8a0e844e88205c2f32513bbbe.
I have delivered a Product to the customer. Now I have upgraded the Product, which includes changes to the database.
Customer wants to upgrade the Product. Now will Flyway help in the migration of Customer data from older version to newer version. Please let me know, if this is a valid use case. The flyway documentation talks about its use during development only.
Flyway allows you to change your database by running a set of scripts in a defined order. These scripts are called 'migrations' as they allow you to 'migrate' your database from one version to another.
The idea is you can start with an an empty database and each migration script will successively bring that database up from empty up to the current version. However, it's also possible to start with an existing database by creating a 'baseline' migration.
As SudhirR said, Flyway's primary use case is to define schema changes. However, it's perfectly possible to change data also. Since Flyway is just running plain SQL, in principle almost anything you can do in a SQL script you can also do in a Flyway migration.
In the case you described it should be possible to use Flyway to migrate the customer database. The steps you could take are:
Generate a sql script that includes the entire DDL (including indexes, triggers, procedures, ...) of the production database. To do this you will need to add insert statements for all the reference data present in the database.
Save this script in your Flyway project as something like 'V1__base_version.sql'
Run the flyway baseline command against your production database
This will set up your production database for use with Flyway
Add a new migration script to migrate your customer's data to the new version
e.g. create new table, copy data from old table to new table, delete old table
Run flyway migrate to upgrade production
These steps are adapted from the Flyway documentation page here.
Of course you should read the Flyway docs and manually test on a throwaway DB before you run anything against production. However I think in principle Flyway could be a good fit for your use case.
Flyway should be used for schema migrations and any reference data (basic data that is required by the system/application in order to function properly).
Putting client specific data migrations would not be a use case. However, if you can represent the data migration "generically" by not using IDs and instead use names or types than it could be a candidate. Meaning if you could write a migration in a way that could be applied to all clients, then that would be the use case to put it in as a flyway migration.
Otherwise data migrations would be applied in some other way outside of the process like requesting special access to the database or having some team that manages the database to apply the scripts.
If you are doing custom data modifications quite often then I'd say something is wrong in some other area of the SDLC and you may need to increase testing so that bugs don't mess up the data in the first place.
The normal way of dealing with Doctrine Migrations is via the standard Commands - during development one runs the commands manually to e.g. run diffs and apply the migrations, and deployment typically involves applying them the by the same approach but automatically. Occasionally when working in a team on a local instance there are new migrations, but I've updated my source from version control rather than done a deployment, so I need to apply the new migrations manually, and I need to know that I need to do that! An improvement could be to display a warning on a rendered webpage that migrations are out of sync and action needs to be taken.
Is there a way to access the Migrations API directly in PHP/Symfony code, so that I could detect a mismatch between committed and applied migrations? I haven't found any documentation about that. I've had an initial poke around the code and it seems heavily skewed towards Commands (reasonably enough).
Firstly, updating your source code from version control, is a deployment too, and applying Doctrine Migrations should be part of that. You should create a check list of all the steps you need to do during a deployment, including rollbacks. Depending on the complexity of the application, many things could go wrong.
To answer you question, you can execute, in your code, a diff migration with the Process component and parse the output to determine if there're migrations to be applied.
My current project has a few Flyway migrations in place that are used to import initial data into a database. This data is convenient especially for developers to be able to quickly setup the project. Production data is imported through some batch jobs and has a newer version.
Some of these migrations are quite big (~20MB) and so everytime the application starts, Flyway takes some time to calculate the checksum of the migrations. This also is a problem for integration tests as they also take longer because of this.
I consider this approach to be a misuse of Flyway, I think migration tools should be used mainly for structural data.
I want to remove those files from our application and rather use a configuration management tool (e.g. Vagrant, Puppet, Chef) to import test data on developer environments. However, I can't just delete the migration files from the application as Flyway will complain that a migration has been recorded in the database but is not present in the application migrations.
My first thinking was to create a new migration with a high-priority version number that will
Delete the test data
Delete the migration from the schema_version table
and then remove the migration scripts. This however does not work, Flyway still complains that the removed migration script is missing.
Is there a restriction that you cannot interact with the schema_version table in migrations?
What other options do I have? If at all possible I want to do this using Flyway and not manually.
Repair is your best bet. Empty those data migrations and run the repair command to have their checksums recalculated based on the empty files.
We have a customer with a IT-department that insist on getting database updates as scripts prior to upgrades (they want to "read" the updates before implementing them).
Being an avid user of flyway it made me think about a way of generating a script from flyway based on updates and send this script to IT. This script would at the very least need to create version table if non-existant, check version and apply needed updates. It would of course be proprietary to database vendor (in my case Oracle).
This would allow us to run updates with flyway automatically in development environments and create manual scripts for test and production.
Are anyone aware of something like that having been contemplated or endeavored before? Would it be trivial or a momentous task?
We had this exact problem when I worked at a consultancy (Intelliware) so the devs there put together some code and pushed it up to GitHub.
We tried unsuccessfully to get it included into the Flyway core repo.
https://github.com/Intelliware/flyway-script-generator