Transactional transaction propagation behavior?

Transaction propagation behaviors include 7 Kind of , Not interacting with the database , Database defined , It is spring The frame comes with .

This article mainly introduces three kinds of ：required、nested、required_new.

Propagation_required（ Communication requirements ）： default , The most common , If there is no current transaction , Execute on the new transaction , If any , Join the current transaction execution . When the peripheral method does not open a transaction , Two internal transactions start this transaction without interfering with each other , And not affected by peripheral abnormalities .

Under the default propagation requirements , If an exception is caught in the inner transaction , Then other programs in this inner transaction run normally . Peripheral transactions caught exceptions , Peripheral and other internal transactions cannot run normally .

Propagation_supports（ Communication support ）： Support current transaction , If there is no business , It's non transactional .Propagation_mandatory（ mandatory ）： If there are currently no transactions , Throw an exception .

Propagation_requires_new： New transaction , If a transaction currently exists , Suspend the current transaction . When the peripheral method does not open a transaction , Two internal transactions start this transaction without interfering with each other , And not affected by peripheral abnormalities .

If the peripheral starts a transaction ,requeired Inner transactions and outer transactions are rolled back at the same time .

if requreis_new Inner transaction exception is not caught , be requeired The inner transaction and outer transaction are rolled back together , other requreis_new Internal affairs are not affected .

if requreis_new The inner transaction exception is trycatch Capture , Then other peripheral affairs will not be affected .

Propagation_not_supported（ Not supported ）： Operate with non transaction , If a transaction currently exists , Let the transaction hang .

Propagation_never： To execute in a non transactional manner , If a transaction currently exists , Throw an exception .

Propagation_nested（ Propagate nesting ）： If there are currently transactions , Then execute within the nest , If there is no transaction , execute Propagation_required operation . When the peripheral method does not open a transaction , Two internal transactions start this transaction without interfering with each other , And not affected by peripheral abnormalities .

1、propagaration_requeire_new And Propagation_nested The difference between nested propagation ：

Nested If peripheral transactions are enabled , Because it is a parent-child nested transaction , Then the sub transactions are rolled back with the rollback of the peripheral main transaction , If the sub transaction rolls back, all transactions will be rolled back together , Unless the current sub transaction is trycatch Capture . and requeires_new Peripheral transactions and inner transactions are two transactions , Rollback of peripheral transactions does not affect internal transactions .

2、Nested and requeired difference ：

Will roll back with the rollback of peripheral transactions .Requeired It belongs to joining peripheral affairs , Because they all belong to the same transaction , Once the inner transaction is rolled back, whether or not trycatch Capture , All rolled back together . and nested It belongs to sub transaction , There is a separate save node , therefore nested Method throws an exception trycatch Capture is rolled back , It will not affect peripheral affairs .

The code example is as follows ：

required example , Use the default transaction instance , Whether or not exceptions are caught , Roll back all together

nested example , Because nested transactions , The outer and inner walls will roll back with each other , Unless the sub transaction is caught exception

required_new example , When the periphery throws an exception , It will not affect the normal storage of internal businesses in the database