I'm experiencing the following issue:
org.flywaydb.core.api.FlywayException: Validate failed: Detected applied migration not resolved locally: 1.44
That happened when I understood that the data that I added in 1.44 is invalid and I don't want to deal with it on old environments, but on new environments I don't want this data. I want the data that I will insert within new migration(e.g. 1.48).
If I change old migration it will fail on old envs due to checksum;
If I leave it, on new envs I will have invalid data from 1.44;
How can I delete it so that I accomplish what I need and not to get an error? What's the correct way?
This questions is related to Best pratice: How to modify flyway migration script after it has been used
The basic answer is: don't delete once it's been applied
It doesn't matter if during the migration process some intermediary state isn't exactly what you want, as long as the final one (1.48 in your case) is correct.
Now if you really need to delete this migration, ask yourself whether replacing it with an empty file could also do the job. If yes you could then follow the advice I gave here: https://stackoverflow.com/a/35491545/350428
Now if that's still not enough and you really really need to delete this migration, delete the file and patch up the flyway_schema_history table by hand to make it consistent again. This is risk-prone and should be an absolute last resort solution.
you can UNDO your migration: UNDO flyway migration
Related
I'm building a Iceberg tables on the top of a data lake. These tables are used for reporting tools. I'm trying to figure out what is the best way to control a version/deploy changes to these tables in CI/CD process. E.g. I could like to add a column to the Iceberg table. To do that I have to write a ALTER TABLE statement, save it to the git repository and deploy via CI/CD pipeline. Tables are accessible via AWS Glue Catalog.
I couldn't find to much info about this in google so if anyone could share some knowledge, it would be much appreciated.
Cheers.
Version control of Iceberg tables.
Agree with #Fokko Driesprong. This is a supplement only.
Sometimes, table changes are considered as part of task version changes. That is, table change statements, ALTER TABLE, are bound to task upgrades.
Tasks are sometimes automatically deployed. So it often executes a table change statement first, and then deploys a new task. If the change is disruptive, then we need to stop the old task first and then deploy the new one.
Corresponding to the upgrade, we also have a rollback script, of course, the corresponding table change statement.
thanks for asking this question. I don't think there is a definitive way of doing this. In practice I see most people bundling this as part of the job that writing to the Iceberg table. This way you can make sure that new columns are populated right away with the new version of the job. If you don't do any breaking changes (such as deletion of column), then the downstream jobs won't break. Hope this helps!
I'm using code migrations in code first. I modified one of my models (domain class) and changes were picked up when I added a migration. So far so good. Now is the part where I may be doing something wrong:
I made additional changes making the previous modification irrelevant.
I deleted the migration and tried to re-scaffold, I got an empty migration. I understand now that the database tracks migration history. So I understand why this was stupid.
My next step was to delete the rows in the database- it also sounds like this is not a good idea. The appropriate way to "step-back" is to do Update-Database -Target:{MigrationName}
Trying both of these I am still getting an empty migration. I also tried dropping the database and updating to the migration before mine.
My google/SO foo has failed me. What I think is happening is that VS/Entity is not detecting changes in my model and I'm not sure what the trigger is. Can someone help me out?
I had a similar problem. My solution was to just go forward with a substance-less migration happening. The only change it makes is adding a record to the __Migration table, but I am living with that and just moving forward.
What are the practical advantages of Doctrine Migrations over just running a schema update?
Safety?
The orm:schema-tool:update command (doctrine:schema:update in Symfony) warns
This operation should not be executed in a production environment.
but why is this? Sure, it can delete data but so can a migration.
Flexibility?
I thought I could tailor my migrations to add stuff like column defaults but this often doesn't work as Doctrine will notice the discrepancy between the schema and the code on the next diff and stomp over your changes.
When you are using the schema-tool, no history of database modification is kept, and in a production/staging environment this is a big downside.
Let's assume you have a complicated database structure in a live project. And in the next changeset you have to alter the database somehow. For example, your users' contact phones need to be stored in a different format, not a VARCHAR, but three SMALLINT columns for country code, area code and the phone number.
Well, that's not so hard to figure out a query that would fetch the current data, separate it into three values and insert them back. That's when migrations come into play: you can create your new fields, then do the transforms and finally drop the field that was holding the data before.
And even more! You can even describe the backwards process (the down migration), when you need to undo the changes introduced in your migration. Let's assume that someone somewhere relied heavily on the format of the VARCHAR field, and now that you've changed the structure, his piece of code is not working as expected. So, you run migration:down, and everything gets reverted. In this specific case you'd just bring back the old VARCHAR column and concatenate the values back, and then drop the fields.
Doctrine's migration tool basically does most of the work for you. When you diff your schema, it generates all the necessary up's and down's, so only thing you'll have to do is handle the data that could be damaged when the migration is applied.
Also, migrations are something that gives other developers on your team knowledge on when it's time to update their schemas. With just the schema-tool, your teammates would have to run doctrine:schema:update each and every time they pull, `cause they wouldn't know if the schema has really changed.
When using migrations, you always see that there are some updates in the migrations folder, which means you need to update your schema.
I think that you indeed nailed it on Safety. With Migrations you can go back to another state of the table (just like you can do in Git version control). With the schema update command you can only UPDATE the tables. There is no log kept for going back in case of a failure with already saved data in those tables. I don't know exactly, but doesn't a migration also saves the data of the corresponding table that's being updated? That would be essential in my opinion, otherwise there is no big reason to use them.
So yes, I personally think that the main reason for using migrations in a production environment is safety and maybe a bit of flexibility. Safety would be the winner here I think :)
Hope this helps.
edit: Here is another answer with references to the Symfony docs: Is it safe to use doctrine2 migrations in production environment with symfony2 and php
You also cant perform large updates with plain doctrine migration. Like try to update index on 30 mln users database. As it will a lot of time while you app will not be accessible.
My project contains a lot of objects like views and stored procedures which are being changed quite frequently. Now I have to create new SQL script on every update which contains complete source code of changed objects despite I've actually changed only few rows. It leads to massive code duplication and I also found it difficult to review these changes.
I'd like to have only one actual version of SQL script for every object like view or procedure and recreate these objects every time I redeploy the database. As result I could change existing source file (like in Java or C programming) instead of creating a new update every time I need to alter view or procedure.
Is there a possibility to execute some scripts every time I migrate the database with Flyway?
I'm not sure why that got so many downvotes, it's a perfectly understandable and valid question. Perhaps it's because it closely resembles this open question:
Migrating Stored Procedures with Flyway
We are actually starting to push against this issue now. We've been using flyway for development and testing (and love it). But we've come to a point where we're starting to have to use procs/triggers/views (p/t/v's) and the fundamental disconnect between how we did it before, and how we must use flyway, is starting to be a strain.
Before, for a given database object (let's say it's a procedure), there'd be one source file. And if you needed to change the proc 'n' times, there would be 'n' versions of the same file in your VCS. Diff tools work great, IDE's all understand this, merges detect when two developers working in separate branches make changes to the proc, etc, etc. You know, old school.
But with flyway, any one proc with 'n' changes is now scattered across 'n' files. Instead of "one object in one file with 'n' versions", you have "one objecct in 'n' files with one change each". I now need to do a text search in my IDE for any instance of "proc_name" if I want to know the history of changes to the proc. The VCS knows nothing about it. Devs can each make a migration in their own branches that succeed when each is deployed, but leave the proc with a missing update.
I'm not saying any of this to complain about flyway, and I fully realize it's not a simple area. I'd almost say it's unsolveable (by flyway).
We're scheming how to handle this problem, and I'd be very interested to know how others have handled it.
Repeatable migrations are supported by Flyway 4.0, now.
Just add sql files starting with "R" without any version information to your migration folder:
R__Blue_cars.sql
You have to ensure, that the script could be repeatable migrated.
This is usually done by "CREATE OR REPLACE" clauses in your DDL statements.
https://flywaydb.org/documentation/migration/repeatable
As title, possible? I have by accident deleted another record due to my ugly html interface in FireFox. The bad thing is this record delete is a root folder which the program automatically cascade delete everything :(
Take a look at undark. I already used it. It it can export the rows (deleted or not) from a SQLite db file if the records were not overwritten. Last version here.
The SQLite-Deleted-Records-Parser does not give the same type of output, but can be useful.
And there are also some products like the SQLite Forensic Explorer, SQLite Repair, Sqlite Database Recovery and SQLiteDoctor.
If you are a developer you can avoid having the same problem again using litereplica. It adds single-master replication to SQLite.
But remember to enable the point-in-time recovery because as the transactions are replicated to the replicas an accidental command like DROP TABLE or DELETE FROM will also be replicated. With PITR you will be able to go to a previous point-in-time.
Or use the Backup API regularly. Although it transfers the entire db on each backup.
And remember: if you copy an SQLite file or use a regular backup approach while a transaction is active
the copy can be corrupted.
Sorry -- nope. Backups are the only option I know of.
In the future, consider never issuing DELETE queries, especially from user-accessible forms (let only the DB admin do it, if anyone) -- just include a field in your tables that marks a record as inactive and then factor that in to your queries in the WHERE clause.
Unfortunately I don't know of a way, either. However, until you do a VACUUM on the SQLite database file the deleted data is generally not technically removed. Perhaps you might be able to still recover some of the data using some sort of hex editor on the file.
It might be possible to go in and see the data via a hex-editor. The only info I could find said that metadata was gone so the records weren't going to come back, but the data itself might still be there. It has a lot to do with how important the data is, I suspect it's not important enough for you to dig out a hex editor.
The data isn't always removed from the file straightaway. If there's lots of it and you're desperate, you could use the UNIX command strings on the file. This may help you to recover various bits and pieces of human-readable data, but it'll be a hard and inaccurate process.
No way. Without a working backup you won't be able to restore this.