[jira] [Created] (IGNITE-11439) MVCC: Error in transaction mode validation.

["Roman Kondakov (JIRA)" <ji...@apache.org>]

Roman Kondakov created IGNITE-11439:
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             Summary: MVCC: Error in transaction mode validation.
                 Key: IGNITE-11439
                 URL: https://issues.apache.org/jira/browse/IGNITE-11439
             Project: Ignite
          Issue Type: Bug
          Components: mvcc
            Reporter: Roman Kondakov
         Attachments: Reproducer

Currently MVCC transaction mode is validated within {{MvccUtils#tx()}} method. If this method is called during execution of {{OPTIMISTIC}} transaction over non-mvcc cache it can cause {{UnsupportedTxModeException}} in the case when at least one mvcc cache is also started in the cluster. This happens due to improper use of {{MvccUtils#mvccEnabled}} method which returns {{true}} if at least one mvcc cache is started. This is a global {{mvccEnabled}} flag, but not a per-cache one.
A very common pattern of using the combination of these two methods is completely wrong:

{code:java}
if (MvccUtils.mvccEnabled(kernalCtx))  <- global check of enabled mvcc
    tx = MvccUtils#tx(kernalCtx)   <- an attempt to get a transaction with wrong assumption of enabled mvcc. Exception is thrown here.
{code}

We need to revise mvcc transaction mode validation and using these methods in the project. All possible scenarios should be covered by tests.

See reproducer in attachment. Error stacktrace is below:

{noformat}
class org.apache.ignite.internal.processors.cache.mvcc.MvccUtils$UnsupportedTxModeException: Only pessimistic transactions are supported when MVCC is enabled.
	at org.apache.ignite.internal.processors.cache.mvcc.MvccUtils.tx(MvccUtils.java:717)
	at org.apache.ignite.internal.processors.cache.mvcc.MvccUtils.tx(MvccUtils.java:696)
	at org.apache.ignite.internal.processors.query.h2.twostep.GridReduceQueryExecutor.query(GridReduceQueryExecutor.java:488)
	at org.apache.ignite.internal.processors.query.h2.IgniteH2Indexing$3.iterator(IgniteH2Indexing.java:1102)
	at org.apache.ignite.internal.processors.cache.QueryCursorImpl.iter(QueryCursorImpl.java:102)
	at org.apache.ignite.internal.processors.cache.query.RegisteredQueryCursor.iter(RegisteredQueryCursor.java:64)
	at org.apache.ignite.internal.processors.cache.QueryCursorImpl.getAll(QueryCursorImpl.java:121)
	at org.apache.ignite.internal.processors.cache.mvcc.CacheMvccSqlTxModesTest.testConsequentMvccNonMvccOperations(CacheMvccSqlTxModesTest.java:64)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.apache.ignite.testframework.junits.GridAbstractTest$7.run(GridAbstractTest.java:2049)
	at java.lang.Thread.run(Thread.java:748)
{noformat}





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