Some tables in the database have constraints on columns with dates. Because of them, the script for moving timestamps can fail from time to time. This PR makes the script work with such tables.
In general, in PostgreSQL it is not always possible to defer constraint checks to the transaction commit (Primary Keys and Unique Constraints can be deferred, but them should be declared as DEFERRABLE to make it possible. Indices created with CREATE UNIQUE INDEX can't be deferred at all).
Since we can't defer constraint checks, I've made it work using a little hack. For example, if we need to move all timestamps by one day, the script will move timestamps by 1000 years and one day, and then return timestamps back by 1000 years. The script use this hack only for columns that have unique constraints.
This will fix the try-reset build that failed today. Probably this going to happen again with other tables that have constraints on date columns. I'm going to modify the script to make it work without ignoring such tables. After that, the only table we're going to need to ignore will be the 2FA table.
Before I fixed that, don't hesitate to tag me if the try-reset build fail again.
Without checking if t.table_schema = '#{@schema}' the SELECT with JOIN in the script were returning every column twice in case there is a 'backup' scheme with exactly the same tables as in the 'public scheme'
We're going to use this script for updating timestamps on Try, but it can be used with a local database during development as well.
Usage:
Commands:
ruby db_timestamp_updater.rb yesterday <date> move all timestamps by x days so that <date> will be moved to yesterday
ruby db_timestamp_updater.rb 100 move all timestamps forward by 100 days
ruby db_timestamp_updater.rb -100 move all timestamps backward by 100 days
The script moves all timestamps in the database by the same amount of days forward or backward. No need to change the script if we add a new column in the future.
The more simple solution would be just to move timestamps in several tables (topics, posts, and so on). I didn't want to go that way because it could generate additional work in the future. For example, if we add a new column with a timestamp and users can see that timestamp we'd need to add that column to the script. Or, for example, if we move a post's timestamp to the future but forget to move a timestamp of topic timer or user action it can cause weird bugs.
Andrei Prigorshnev