[IGNITE-4188] Savepoints support inside of Ignite Transactions

• Type: Task
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Assignee: Unassigned
• Reporter: Denis A. Magda
• Created: 08/Nov/16 19:19
• Updated: 25/Jan/21 16:30

Description

A savepoint is a special mark inside a transaction that allows all commands that are executed after it was established to be rolled back, restoring the transaction state to what it was at the time of the savepoint.

Here is a reference to the similar functionality implemented by some of RDBMs vendors.
https://www.postgresql.org/docs/8.1/static/sql-savepoint.html
https://docs.oracle.com/cd/B19306_01/server.102/b14200/statements_10001.htm
http://dev.mysql.com/doc/refman/5.7/en/savepoint.html

Consider the following example.

BEGIN;
INSERT INTO table1 VALUES (1); 
SAVEPOINT my_savepoint; 
INSERT INTO table1 VALUES (2); 
ROLLBACK TO SAVEPOINT my_savepoint; 
INSERT INTO table1 VALUES (3); 
COMMIT;

The execution result must guarantee that only values 1 and 3 are inserted into table1.

In Ignite, it should be supported this way (preserving the same behavior as above).

Ignite ignite = ....;
IgniteCache<Integer, Integer> c = ....;

try (Transaction tx = ignite.transactions().txStart()) {    
    c.put(1, 1);
    
    tx.savepoint("mysavepoint");
    
    c.put(2, 2);
    
    tx.rollbackToSavepoint("mysavepoint");
    
    c.put(3, 3);
    
    tx.commit();
}

As a summary the following has to be supported on Ignite side:

• The savepoint method which will set a named transaction savepoint with a name of an identifier.
• Multiple savepoints defined within a transaction. The names of the savepoints have to differ from each other. If the current transaction has a savepoint with the same name, the old savepoint is deleted and a new one is set.
• The rollbackToSavepoint method that will roll back all the changes done after a specific checkpoint establishment.
• The releaseCheckpoint method that will destroy a savepoint, keeping the effects of commands executed after it was established.
• Full support of the behavior listed above at the level of ODBC and JDBC drivers and DML (will be handled under separate tickets).
• The behavior has to be support for all transactional modes.

Original proposal on the dev list:
http://apache-ignite-developers.2346864.n4.nabble.com/TX-savepoints-td12041.html

Deadlock detection should be addressed and possibly updated to work properly with presence of savepoints. See linked ticket.

Issue Links

• relates to: IGNITE-11228 MVCC: Implement transaction savepoints.
• relates to: IGNITE-9322 MVCC: implement deadlock detector
• links to: CI tests
• links to: GitHub Pull Request #1815
• links to: Upsource

Sub-Tasks

• JDBC Driver: support transactional savepoints: Open
• ODBC Driver: support transactional savepoints: Open