[tor-bugs] #5232 [BridgeDB]: Import bridges into BridgeDB in a separate thread and database transaction

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#5232: Import bridges into BridgeDB in a separate thread and database transaction
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 Reporter:  karsten   |          Owner:  aagbsn
     Type:  defect    |         Status:  new   
 Priority:  major     |      Milestone:        
Component:  BridgeDB  |        Version:        
 Keywords:            |         Parent:  #4499 
   Points:            |   Actualpoints:        
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Comment(by aagbsn):

 After some coffee:

 Bridges are placed in BridgeRings in memory; so this will be more
 complicated than just a db transaction.

 One possible solution could be to create a new copy of these
 datastructures and then swap atomically.

 It might look something like this:

 (in Main.py, load())

 1. create a new thread
 2. create new splitter(s) and rings
 3. get a db transaction
 4. insert bridges
 5. get a lock
 6. swap the datastructures
 7. commit the transaction
 8. release the lock

 Things to check when testing:

 1. BridgeDB should serve up bridges during the update process
 2. The email distributor touches the database. Make sure it works properly
 during the update.
 3. Additional HUPs should not deadlock.
 4. Make sure that any references held by distributors are updated
 properly.

 Anything else I forgot?

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/5232#comment:1>
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