I am currently investigating Flyway as an alternative to Liquibase, but was unable to find an answer to the following question in the documentation:
Assume a migration X is found to contain a bug after deployment in production. In retrospect, X should never have been executed as is, but it's already too late. However, we'd like to replace the migration X with a fixed version X', such that databases that are populated from scratch do not suffer from the same bug.
In Liquibase, you would fix the original changeset and use the <validChecksum> tag to notify Liquibase that the change was made by purpose. Is there a pendant to <validChecksum> in Flyway, or an alternative mechanism that achieves the same?
Although it is a violation of Flyway's API, the following approach has worked fine for us:
Write a beforeValidate.sql that fixes the checksum to match the expected value, so that when Flyway actually validates the checksum, everything seems fine.
An example:
-- The script xyz/V03_201808230839__Faulty_migration.sql was modified to fix a critical bug.
-- However, at this point there were already production systems with the old migration file.
-- On these systems, no additional statements need to be executed to reflect the change,
-- BUT we need to repair the Flyway checksum to match the expected value during the 'validate' command.
UPDATE schema_version
SET checksum = -842223670
WHERE (version, checksum) = ('03.201808230839', -861395806);
This has the advantage of only targetting one specific migration, unlike Flyway's repair command.
Depending how big the mess is you could also
simply have a follow-up migrations to correct it (typo in new column name, ..)
if that is not an option, you must manually fix both the migration and the DB and issue Flyway.repair() to realign the checksum http://flywaydb.org/documentation/command/repair.html
What is the point of hiding this bad change if it has already reached production? Is it expensive to replay every time on empty databases (I assume CI runs) ? Make a new db baseline with that migration already included.
Related
Good afternoon,
I want to write the dbt test values to a specific table in my data warehouse.
I have tested multiple schema inclusions in all the possible .yml files and I am not really finding the correct place to specify to which database I want the tests to be recorded.
Nowadays, it always answers me with the error of not having the permissions to perform a glue:CreateDatabase action, which in fact is not what I want to do, but rather write to table specified by me.
To conclude, what I am asking here is how can I specify where the dbt tests results are being written, instead of letting dbt create and store the values in the default schemas?
If somebody could help me on this I would really appreciate it!
Well, I managed to fix it, I was almost throwing my computer away, because I didn't have more air to pull off, but basically we can specify the target database in the dbt_project.yml. To do that, just add to the dbt_project.yml
tests:
+store_failures: true
+schema: "path that you want"
I did not find any information in dbt documentation, neither community forums, so it was just an iterative process of testing possible approaches
Problem:
I imported a small package of about 15 items from one of our DBs to another one and somehow in the process the children of one of the items got overwritten by this operation.
I may have incorrectly selected "overwrite" instead of "merge" but I'm not sure about that.
The worst thing is, I also published to the web DB after import, so the items are not in the web DB either.
Things I checked:
Checked the Recycle Bin, not there
Also checked the Archive, not there either
Even wrote a piece of code to find the items by ID in the DB, FAILED
My question:
Are the items overwritten by Launch Wizard gone forever? Or there could still be a trace of them remaining in the DB?
There is no "rollback or uninstall a package" feature out of the box in Sitecore. This seems to be the only available info regarding the matter.
I've heard of some shared source modules which could be useful, but never tried them personally.
I think, your best choice is to restore items from a database backup or revert content, if you have a serialized copy on the file system.
I have an application written in C++ which uses an SQLite database to store information. I need a way of assigning a version number to the database. By this I mean, I need to be able to assign a version number to the state of the database, and if a new 'state' (version) is available, then I need to update the current database state to match the state of the updated version.
I am wondering whether it would be good practice to store the information required for this to happen in a table. I would need the version number, and then some way of storing the tables and their columns related to each version number. This would allow me to make comparisons etc.
I realise that this question Set a version to a SQLite database file is related, however it doesn't quite answer my question, as I am unsure if my approach is correct, and if so, how I go about achieving this.
All help is much appreciated.
Use PRAGMA user_version to read and store an integer value in the database file.
When the version in your code and database file are the same, do nothing. When they are different, upgrade/downgrade accordingly and update the version number.
Today I have started my first steps into postgresql, since its recommended by the Django team.
I came across several issues, that I solved patiently one by one.
1) Creating tables under postgresql requires to login as a different OS login, from which you don't even know the password. Fine, I found the solution and created the database.
2) After running syncdb, you can't simply execute a simple insert sql like this:
INSERT INTO App_contacttype (contact_type, company_id) VALUES ('Buyer', 1),('Seller', 1);
Since Django creates it with quotes the table becomes case sensitive, hence it has to be like this:
INSERT INTO "App_contacttype" (contact_type, company_id) VALUES ('Buyer', 1),('Seller', 1);
But the problems seem never to end. Now suddenly the execution of the insert script says
ERROR: value too long for type character varying(40)
SQL state: 22001
In MySQL this was no problem. I don't know, right now I am getting a bit of cold feet, maybe I should just stick to MySQL.
The only reason I was considering postgresql was that some research suggested postgresql has much better support for changing Schemas along the way than MySQL.
However considering http://south.aeracode.org/ would take away all the pain of syncing Schemas, would I even need to worry about Schema changes at all no matter what the underlying database is?
today I ran into an error and have no clue how to fix it.
Error: App with label XYZ could not be found. Are you sure your INSTALLED_APPS setting is correct?
Where XYZ stands for the app-name that I am trying to reset. This error shows up every time I try to reset it (manage.py reset XYZ). Show all the sql code works.
Even manage.py validate shows no error.
I already commented out every single line of code in the models.py that I touched the last three months. (function by function, model by model) And even if there are no models left I get this error.
Here http://code.djangoproject.com/ticket/10706 I found a bugreport about this error. I also applied one the patches to allocate the error, it raises an exception so you have a trace back, but even there is no sign in what of my files the error occurred.
I don't want to paste my code right now, because it is nearly 1000 lines of code in the file I edited the most.
If someone of you had the same error please tell me were I can look for the problem. In that case I can post the important part of the source. Otherwise it would be too much at once.
Thank you for helping!!!
I had a similar problem, but I only had it working after creating an empty models.py file.
I was running Django 1.3
Try to clean up all your build artifacts: build files, temporary files and so on. Also ./manage.py test XYZ will show you stack trace. Later try to run python with -m pdb option and step through the code to see where you fail and why.
You don't specify which server you're using. With Apache you'll almost certainly need a restart for things to take effect. If you're using the development one try restarting that. If this doesn't work you may need to give us some more details.
I'd also check your paths as you may have edited one file but you may be using a different one.
Plus check what's still in your database, as some of your previous versions may be interfering.
Finally as a last resort I'd try a clean install (on another django instance) and see if that goes cleanly, if it does then I'd know that I'd got a conflict, if not then the problem's in the code.