2point0/Android-Database-Locking-Collisions-Example

Show db locking and collisions with multiple connections

Example app showing how you can cause DB collisions pretty easily with multiple SQLiteHelper instances.

Also demonstrate dramatic time difference using transactions.

Button	:Description
1 Write	:Perform writes from multiple threads using only one instance of a DatabaseHelper. This should never cause a failure
+ Write	:Perform writes from multiple threads, each thread with its own DatabaseHelper. First failure in a thread will end that thread leaving only one thread able to complete it's process. The ticker bar should have one dominant color [blue,white,yellow,red] (red at beginning and end signify start and end of run)
1 Write + Read	:One thread performs writes while other threads perform reads. All threads have their own copy of DatabaseHelper. Failures can occur but if you're lucky, they won't.
+ Read	:All threads perform reads with their own copy of DatabaseHelper. Failures can occur but if you're lucky, they won't.
Test Transaction Isolation	:Interleaving reads and writes with the same copy of DatabaseHelper will not fail but transactions are exclusive and cannot be disturbed.
No Transaction	:Perform a timed series of writes individually 
Transaction :Perform a timed series of writes in a transaction
Exclusive No Yielding	:One long running transaction and many short running transactions are performed. Each transaction is exclusive and must complete before another transaction/operation is allowed. The ticker bar should show the long transaction finishing before trailing short transactions run.
Safely Contended Yield	:One long running transaction yielding at times to allow short running transactions to perform their operations. The ticker bar should show short transactions finishing before the long transaction finishes.
No Yield Read	:A thread performing writes in a transaction is followed by other threads performing reads. The write transaction must complete before reads can be made
Yield and Read	:A thread performing writes in a transaction yields to following threads performing reads. The yielding allows a few reads to execute before waiting for the entire write transaction to complete.