It pauses Sidekiq, clears Redis (namespaced to the current site), clears Sidekiq jobs for the current site, restores the database and unpauses Sidekiq. Previously it stayed paused until the end of the restore.
Redis is cleared because we don't want any old data lying around (e.g. old Sidekiq jobs). Most data in Redis is prefixed with the name of the multisite, but Sidekiq jobs in a multisite are all stored in the same keys. So, deleting those jobs requires a little bit more logic.
After restoring a backup it takes up to 48 hours for uploads stored on S3 to appear in the S3 inventory. This change prevents alerts about missing uploads by preventing the EnsureS3UploadsExistence job from running in the first 48 hours after a restore. During the restore it deletes the count of missing uploads from the PluginStore, so that an alert isn't triggered by an old number.
That commit introduced a bug to the system: f69dacf979
Restore works fine for multisite, however, stopped working for non-multisite.
Reason for that was that `establish_connection` method got a check if the multisite instance is available:
```
def self.instance
@instance
end
def self.establish_connection(opts)
@instance.establish_connection(opts) if @instance
end
```
However, the reload method don't have that check
```
def self.reload
@instance = new(instance.config_filename)
end
```
To solve it, let's ensure we are in a multisite environment before call reload
Temporarily recreate already dropped functions in the discourse_functions schema in order to allow restoring of backups which still reference dropped functions.
In order for this to work the Backuper stores a couple of site settings
in the new backup_metadata table, because the old setting values might
not be available on restore anymore.
This reduces chances of errors where consumers of strings mutate inputs
and reduces memory usage of the app.
Test suite passes now, but there may be some stuff left, so we will run
a few sites on a branch prior to merging
* Logs exceptions during the cleanup phase, but doesn't stop executing subsequent cleanup tasks.
* Notifies the user at the end of the cleanup phase, so that the log contains possible errors during that phase.
Introduce new patterns for direct sql that are safe and fast.
MiniSql is not prone to memory bloat that can happen with direct PG usage.
It also has an extremely fast materializer and very a convenient API
- DB.exec(sql, *params) => runs sql returns row count
- DB.query(sql, *params) => runs sql returns usable objects (not a hash)
- DB.query_hash(sql, *params) => runs sql returns an array of hashes
- DB.query_single(sql, *params) => runs sql and returns a flat one dimensional array
- DB.build(sql) => returns a sql builder
See more at: https://github.com/discourse/mini_sql
* `rescue nil` is a really bad pattern to use in our code base.
We should rescue errors that we expect the code to throw and
not rescue everything because we're unsure of what errors the
code would throw. This would reduce the amount of pain we face
when debugging why something isn't working as expexted. I've
been bitten countless of times by errors being swallowed as a
result during debugging sessions.
