CODEWITHSUNDEEP
springpostgresqlhibernatetransactionsspring-data
Aliaksei Stadnik
Aliaksei Stadnik

Reputation: 1948

Spring Data JPA does not work with transaction isolation "READ_UNCOMMITTED"

There are two threads, and two transactions bound to each thread:

DEBUG o.s.orm.jpa.JpaTransactionManager - Creating new transaction with name [com.workflow.consumer.RecordEventConsumer$MockitoMock$1882263982.handleRecordsAddedEvent]: PROPAGATION_REQUIRED,ISOLATION_READ_UNCOMMITTED; ''

Creating new transaction with name [com.workflow.statemachine.action.CreateContentAction.execute]: PROPAGATION_REQUIRED,ISOLATION_READ_UNCOMMITTED; ''

Both isolation levels are READ_UNCOMMITTED. But when first thread insert something in database with 

repository.saveAndFlush(contextObject)

Where repository is JpaRepository<T, I> repository

And there are actual logs that insertion happened DEBUG org.hibernate.SQL - insert into task_unit ...etc

The transaction from second thread still could not retrieve this very object with neither of this: 

repository.getOne(id);
repository.findOne(id);
entityManager.find(class, id);

More than this, I've tried to connect to the db directly and fire 

BEGIN TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;
SELECT * from task_unit

And still no success.

Do I miss something ?

Upvotes: 2

Views: 1450

Answers (1)

Vao Tsun
Vao Tsun

Reputation: 51426

If I read your question right, then this manual excepr answers:

https://www.postgresql.org/docs/9.6/static/transaction-iso.html

In PostgreSQL, you can request any of the four standard transaction isolation levels, but internally only three distinct isolation levels are implemented, i.e. PostgreSQL's Read Uncommitted mode behaves like Read Committed. This is because it is the only sensible way to map the standard isolation levels to PostgreSQL's multiversion concurrency control architecture.

emphasis mine

Upvotes: 6

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