Denis Magda created IGNITE-4188:
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Summary: Savepoints support inside of Ignite Transactions
Key: IGNITE-4188
URL: https://issues.apache.org/jira/browse/IGNITE-4188
Project: Ignite
Issue Type: Task
Reporter: Denis Magda
Fix For: 2.1
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.
{code}
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;
{code}
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).
{code}
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();
}
{code}
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.
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