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From "Lily Wei (JIRA)" <j...@apache.org>
Subject [jira] Commented: (DERBY-4314) With derby client setTransactionIsolation executes and commits even if isolation has not changed
Date Wed, 28 Apr 2010 22:13:49 GMT

    [ https://issues.apache.org/jira/browse/DERBY-4314?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12861965#action_12861965
] 

Lily Wei commented on DERBY-4314:
---------------------------------

At this point, I am hesitate to keep working on piggy-backing fix due to the fact that we
can not execute a statement in the local transaction when we rejoin to the global transaction
per Kathey's example( please see ReproIsoLost.java). With DERBY-4314-5 fix, we don't commit
when calling setTransactionIsolation(). However, we do have performance issue when connection
is not cache. We will have server round-trip when we first call seTransactionIsolation when
creating the connection, we will have two round trip when isolation is not set to READ_COMMITTED
(check + change) In any case, DERBY-4314-5 do fix setTransctonIsolation() not perform commit
issue. Therefore, I am leading toward to submit DERBY-4314-5 change and open a new JIRA for
the performance issue. From the new JIRA, we can investigate further about the piggybacking
issue and beyond and have conclusion on this issue and DERBY-4343. Is this sound like a reasonable
solution for this issue?

> With derby client setTransactionIsolation executes and commits even if isolation has
not changed 
> -------------------------------------------------------------------------------------------------
>
>                 Key: DERBY-4314
>                 URL: https://issues.apache.org/jira/browse/DERBY-4314
>             Project: Derby
>          Issue Type: Improvement
>          Components: JDBC, Network Client
>    Affects Versions: 10.1.3.1, 10.2.2.0, 10.3.3.0, 10.4.2.0, 10.5.1.1, 10.6.1.0
>            Reporter: Kathey Marsden
>            Priority: Minor
>         Attachments: DERBY-4314-2.diff, DERBY-4314-3.diff, DERBY-4314-5.diff, derby-4314-6a-initial_piggybacking.diff,
derby-4314-6a-initial_piggybacking.stat, DERBY-4314-6b-combinepiggybacking.diff, DERBY-4314-6c-combineaftermerge.diff,
DERBY-4314.diff, ReproIsoLost.java, TestConnReuse.java, utilXid.java
>
>
> With in EmbedConnection.setIsolation() we have a check to see if the isolation level
is the same and if so just return without doing a commit:
>   public void setTransactionIsolation(int level) throws SQLException {
> 		if (level == getTransactionIsolation())
> 			return;
> with org.apache.derby.client.am.Connection we have no such check. It would be good if
the client driver acted like embedded.

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