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https://issues.apache.org/jira/browse/CALCITE-5009?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17490697#comment-17490697
]
Istvan Toth commented on CALCITE-5009:
--------------------------------------
Ultimately, createConnection()
{noformat}
org.apache.calcite.avatica.AvaticaClientRuntimeException: Remote driver
error:
RuntimeException: Connection already exists:
e1cbaa54-dd66-461e-8bee-15d6a6296581 at
org.apache.calcite.avatica.remote.Service$ErrorResponse.toException(Service.java:2475)
at
org.apache.calcite.avatica.remote.RemoteProtobufService._apply(RemoteProtobufService.java:62)
at
org.apache.calcite.avatica.remote.ProtobufService.apply(ProtobufService.java:81)
at
org.apache.calcite.avatica.remote.RemoteMeta$3.call(RemoteMeta.java:114) at
org.apache.calcite.avatica.remote.RemoteMeta$3.call(RemoteMeta.java:110) at
org.apache.calcite.avatica.AvaticaConnection.invokeWithRetries(AvaticaConnection.java:793)
at
org.apache.calcite.avatica.remote.RemoteMeta.openConnection(RemoteMeta.java:109)
at
org.apache.calcite.avatica.AvaticaConnection.openConnection(AvaticaConnection.java:154)
at
org.apache.calcite.avatica.AvaticaConnection.invokeWithRetries(AvaticaConnection.java:797)
at
org.apache.calcite.avatica.remote.RemoteMeta.connectionSync(RemoteMeta.java:134)
at
org.apache.calcite.avatica.remote.RemoteMeta$1.call(RemoteMeta.java:88) at
org.apache.calcite.avatica.remote.RemoteMeta$1.call(RemoteMeta.java:85) at
org.apache.calcite.avatica.AvaticaConnection.invokeWithRetries(AvaticaConnection.java:793)
at
org.apache.calcite.avatica.remote.RemoteMeta.createStatement(RemoteMeta.java:84)
at
org.apache.calcite.avatica.AvaticaStatement.<init>(AvaticaStatement.java:115)
at
org.apache.calcite.avatica.AvaticaStatement.<init>(AvaticaStatement.java:101)
at
org.apache.calcite.avatica.AvaticaJdbc41Factory$AvaticaJdbc41Statement.<init>(AvaticaJdbc41Factory.java:118)
at
org.apache.calcite.avatica.AvaticaJdbc41Factory$AvaticaJdbc41Statement.<init>(AvaticaJdbc41Factory.java:114)
at
org.apache.calcite.avatica.AvaticaJdbc41Factory.newStatement(AvaticaJdbc41Factory.java:76)
at
org.apache.calcite.avatica.AvaticaConnection.createStatement(AvaticaConnection.java:343)
at
org.apache.calcite.avatica.AvaticaConnection.createStatement(AvaticaConnection.java:167)
at
org.apache.calcite.avatica.AvaticaConnection.createStatement(AvaticaConnection.java:63)
at
org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:379) at
<application part deleted> {noformat}
> Make sure transaparent jdbc connection re-creation does not lead to data loss
> -----------------------------------------------------------------------------
>
> Key: CALCITE-5009
> URL: https://issues.apache.org/jira/browse/CALCITE-5009
> Project: Calcite
> Issue Type: Bug
> Components: avatica
> Reporter: Istvan Toth
> Priority: Major
>
> Currently, if the server-side JDBC connection goes away for any reason
> * Avatica connection cache expiry
> * LB/HA Failover
> * Some problem with the "real" connection
> we attempt to create a new "real" JDBC connection, and continue using that
> instead of the original connection
> [https://github.com/apache/calcite-avatica/blob/fbdcc62745a0e8920db759fb6bdce564d854e407/core/src/main/java/org/apache/calcite/avatica/AvaticaConnection.java#L796]
> This is fine for most read-only connections, but it can break transaction
> semantics, which is captured in the "real" connection object.
> {noformat}
> conn.setAutocommit(false)
> stmt = conn.createStatement()
> execute(insert A)
> //Connection lost and object recreated which now proxies a new "real"
> connection
> execute(insert B)
> conn.commit()
> //We have lost "insert A"{noformat}
> I'm not sure if we synchronize autocommit state of the new connection to the
> lost one or not, but it's bad either way.
>
> We should either completely drop this feature, add some logic that avoids it
> if there is an open transaction and/or only allow it for connections that
> have the readOnly flag set.
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