org.neo4j.kernel

Interface TransactionBuilder

public interface TransactionBuilder

A builder for controlling certain behaviors of a transaction. Methods that return TransactionBuilder returns a new instance with the updated configuration that the method call modified. When the behavior is as desired a call to begin() will begin the transaction and return a Transaction.

 // To begin a transaction with default behavior
 Transaction tx = graphDb.tx().begin();
 
 // To begin a transaction with relaxed force
 Transaction tx = graphDb.tx().unforced().begin();
 
 // To have relaxed force optionally set by a condition
 TransactionBuilder txBuilder = graphDb.tx();
 if ( condition )
 {
     txBuilder = txBuilder.unforced();
 }
 Transaction tx = txBuilder.begin();
 

Author:

Mattias Persson

Method Summary

Methods

Modifier and Type	Method and Description
Transaction	begin() Starts a new transaction and associates it with the current thread.
TransactionBuilder	unforced() Relaxes the forcing constraint of the logical logs for this transaction so that the data is written out, but not forced to disk.

Method Detail

begin

Transaction begin()

Starts a new transaction and associates it with the current thread.

Returns:

a new transaction instance

unforced

TransactionBuilder unforced()

Relaxes the forcing constraint of the logical logs for this transaction so that the data is written out, but not forced to disk. Pros

• The overhead of committing a transaction is lowered due to the removal of the force, i.e. I/O waiting for the disk to actually write the bytes down. The smaller the transaction the bigger percentage of it is spent forcing the logical logs to disk, so small transactions get most benefit from being unforced.

Cons

• Since there's no guarantee that the data is actually written down to disk the data provided in this transaction could be lost in the event of power failure or similar. It is however guaranteed that the data that has been written to disk is consistent so the worst case scenario for unforced transactions is that a couple of seconds (depending on write load) worth of data might be lost in an event of power failure, but the database will still get back to a consistent state after a recovery.

Returns:

a TransactionBuilder instance with relaxed force set.