Schema migration - tracking issue

[MarinPostma]

implements the happy path of schema migration. do not use this feature yet.

Here a list of remaining work to get schema migration working properly:

• [x] move all the migration-related stuff from the meta_store to the schema module; let the scheduler use its own connection to the meta store. (#1131)
• [x] migration-specific result builder (#1146 )
• [x] perform error handling, check migration success status, use custom QueryResultHandler to collect results (#1146)
• [x] ensure that the temp table enqueued_tasks is updated corectly after a task is popped when a tasks status changed (maybe use a trigger?) (#1126)
• [x] handle abort; first when a dry run failed, then if a user abort the migration before the dry-run is complete (#1163)
• [x] prevent a job from being enqueued if there is still a pending job for that namespaces (#1131)
• [x] prevent writes while there is are pending jobs in a database (https://github.com/tursodatabase/libsql/pull/1139)
• [x] backup database before starting migration (#1140)
• [x] backup meta store after enqueue job (#1144)
• [x] track version schema
• [ ] go through all todos that I left in the code
• [x] when performing a task, and that task was already performed, report the status, and don't re-perform the task (#1136)
• [x] When a new db is created with a shared schema, bootstrap schema with current schema version. (#1154)
• [x] prevent db creation while schema has pending migration it (#1137)
• [x] admin API collect status of job (#1134)
• [x] shared schema options should only be settable at creation (not possible through config update)
• [x] ensure migration doesn't contain any transaction statements (#1149)
• [x] deadlock in ns_loaded_with_pending_tasks_writes_is_blocked (#1173)
• [x] prevent new migrations if a namespace creation is under way. (i.e. a new namespace creation should not miss fresh migration) (#1183)
• [ ] test schema delete

[haaawk]

what's also missing I think is cloning schema to newly created db that links to existing schema

[MarinPostma]

Add whatever you can think of to the list

[haaawk]

Can we close this @MarinPostma ?