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Second thread is blocked until the first thread commit the transaction, I can not understand why...

raminaa niilian
Ranch Hand

Joined: Jul 14, 2005
Posts: 551
Hi
I am learning transaction and isolation levels. I tried to use read_committed in one thread and then in another thread insert some data into a table. the reader thread is blocked and waits until the first thread commit the transaction to complete the select statement. What I can not understand is: shouldn't the second thread only read what is already committed instead of waiting until the inserting thread finishes its job?

Inserted thread code:



reader thread code:


also I tried and execute these code in two different application and the result is the same. The reader application waits for almost 20 seconds before it read the data.
 
It is sorta covered in the JavaRanch Style Guide.
 
subject: Second thread is blocked until the first thread commit the transaction, I can not understand why...