Hi,
AFAIK, if external connection goes down, then linked table access throw and
DbException thar wrap the original SQLException and not try to do anything more.
If you need more control over this external connection you will need do all the
job in an UDF.
You can request a new feature add for auto-reconnect of a linked connection as
a or try to patch yourself.
Anyway you have a real access problem to your MySql form
org.jboss.resource.adapter.jdbc , I would dig this problem first.
regards,
Dario
El 02/12/10 14:26, kimyx escribió:
> We're using h2 (-1.2.130.jar) in a jboss server environment, where the
> main database is mysql and h2 primarily provides a way to alias
> various in-memory artifacts. Also, some of the mysql tables are set up
> as linked tables like this:
>
> create linked table
> attribute('javax.naming.InitialContext','java:UIDatasource',NULL,NULL,'ATTRIBUTE')
> READONLY
>
> This works fine initially. However, if the jdbc connection from the h2
> linked table to the jndi datasource is lost, it appears that it will
> not reconnect.
>
> I've set the jndi datasource connection parameters to avoid idle-
> timeout, but sometimes the connection is lost anyway, leading to the
> following error:
>
> Error accessing linked table with SQL statement "SELECT * FROM
> ATTRIBUTE T", cause: "com.mysql.jdbc.CommunicationsException:
> Communications link failure due to underlying exception:
>
> ** BEGIN NESTED EXCEPTION **
>
> java.net.SocketException
> MESSAGE: Connection reset
>
> STACKTRACE:
>
> java.net.SocketException: Connection reset
> at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:96)
> at java.net.SocketOutputStream.write(SocketOutputStream.java:136)
> at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:
> 65)
> at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:123)
> at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:2744)
> at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1612)
> at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1723)
> at com.mysql.jdbc.Connection.execSQL(Connection.java:3283)
> at
> com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:
> 1332)
> at
> com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:
> 1467)
> at
> org.jboss.resource.adapter.jdbc.WrappedPreparedStatement.executeQuery(WrappedPreparedStatement.java:
> 342)
> at org.h2.index.LinkedIndex.find(LinkedIndex.java:127)
> at org.h2.index.IndexCursor.find(IndexCursor.java:127)
> at org.h2.table.TableFilter.next(TableFilter.java:253)
> at org.h2.command.dml.Select.queryFlat(Select.java:488)
> at org.h2.command.dml.Select.queryWithoutCache(Select.java:555)
> at org.h2.command.dml.Query.query(Query.java:233)
> at org.h2.command.CommandContainer.query(CommandContainer.java:80)
> at org.h2.command.Command.executeQuery(Command.java:132)
> at org.h2.server.TcpServerThread.process(TcpServerThread.java:272)
> at org.h2.server.TcpServerThread.run(TcpServerThread.java:131)
> at java.lang.Thread.run(Thread.java:619)
>
> Is there a way to automatically reconnect when this happens?
>
> We can set up similar functionality using an alias that makes the
> connection every time, but it is slower and doesn't get indexed like a
> linked table.
>
> Thanks,
> Kim
>
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