[ http://issues.apache.org/jira/browse/DERBY-1559?page=all ]
Andreas Korneliussen updated DERBY-1559:
----------------------------------------
Attachment: DERBY-1559v4.diff
Thanks for reviewing the patch. Attached is a patch where I try to address the
issue w.r.t preserving the information in the DRDAProtocolException, if thrown
during streaming. The DRDAProtocolException will be logged from the DDMReader,
which has access to the DRDAConnThread, before being thrown again.
I have also considered some other options, like making DRDAProtocolException
inherit from IOException or make a new IOException subclass, which is able to
preserve the stack trace from the cause (in JDK 1.3). I did not do that, since
1. by making DRDAProtocolException inherit from IOException, I would proably
need to go through all code and check for catching of IOException (which then
would also catch DRDAProtocolException)
2. since we probably soon will stop supporting 1.3, I did not create a new
IOException subclass.
(ironically DRDAProtocolException seems to usually be thrown as a consequence
of an IOException)
> when receiving a single EXTDTA object representing a BLOB, the server do not
> need to read it into memory before inserting it into the DB
> ----------------------------------------------------------------------------------------------------------------------------------------
>
> Key: DERBY-1559
> URL: http://issues.apache.org/jira/browse/DERBY-1559
> Project: Derby
> Issue Type: Sub-task
> Components: Network Server
> Affects Versions: 10.2.1.0, 10.3.0.0, 10.2.2.0
> Reporter: Andreas Korneliussen
> Assigned To: Andreas Korneliussen
> Attachments: DERBY-1559.diff, DERBY-1559.stat, DERBY-1559v2.diff,
> DERBY-1559v3.diff, DERBY-1559v4.diff, serverMemoryUsage.xls
>
>
> When streaming a BLOB from the Network Client to the Network Server, the
> Network server currently read all the data from the stream and put it into a
> byte array.
> The blob data is then inserted into the DB by using
> PreparedStatement.setBytes(..)
> and later
> PreparedStatement.execute()
> To avoid OutOfMemoryError if the size of the Blob is > than total memory in
> the VM, we could make the network server create a stream which reads data
> when doing PreparedStatement.execute(). The DB will then stream the BLOB
> data directly from the network inputstream into the disk.
> I intent to make a patch which does this if there is only one EXTDTA object
> (BLOB) sent from the client in the statement, as it will simplify the
> implementation. Later this can be improved further to include CLOBs, and
> possibly to include the cases where there are multiple EXTDTA objects.
> --
> CLOBs are more complex, as there need to be some character encoding. This can
> be achieved by using a InputStreamReader, and use
> PreparedStatement.setCharacterStream(..). However the size of the stream is
> not necessarily the same as the size of the raw binary data, and to do this
> for CLOBs, I would need the embedded prepared statements to support the new
> setCharacterStream() overloads in JDBC4 (which do not include a length
> atribute)
> --
> Multiple EXTDATA objects are also more complex, since one would need to have
> fully read the previous object ,before it is possible to read the next.
> --
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