PostgreSQL archive reader exception

[jbobnar]

The following exceptions happened occasionally.

org.postgresql.util.PSQLException: ERROR: portal "C_8" does not exist
  at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2198)
  at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1927)
  at org.postgresql.core.v3.QueryExecutorImpl.fetch(QueryExecutorImpl.java:2130)
  at org.postgresql.jdbc2.AbstractJdbc2ResultSet.next(AbstractJdbc2ResultSet.java:1917)
  at org.csstudio.archive.reader.rdb.RawSampleIterator.next(RawSampleIterator.java:154)
  at org.csstudio.trends.databrowser2.archive.ArchiveFetchJob$WorkerThread.run(ArchiveFetchJob.java:140)
  at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
  at java.util.concurrent.FutureTask.run(FutureTask.java:266)
  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
  at java.lang.Thread.run(Thread.java:745)

org.postgresql.util.PSQLException: Cannot change transaction read-only property in the middle of a transaction.
  at org.postgresql.jdbc2.AbstractJdbc2Connection.setReadOnly(AbstractJdbc2Connection.java:741)
  at org.csstudio.archive.reader.rdb.RDBArchiveReader.<init>(RDBArchiveReader.java:106)
  at org.csstudio.archive.reader.rdb.RDBArchiveReader.<init>(RDBArchiveReader.java:81)
  at org.csstudio.archive.reader.rdb.RDBArchiveReaderFactory.getArchiveReader(RDBArchiveReaderFactory.java:48)
  at org.csstudio.archive.reader.ArchiveRepository.getArchiveReader(ArchiveRepository.java:111)
  at org.csstudio.trends.databrowser2.archive.ArchiveFetchJob$WorkerThread.run(ArchiveFetchJob.java:126)
  at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
  at java.util.concurrent.FutureTask.run(FutureTask.java:266)
  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
  at java.lang.Thread.run(Thread.java:745)