[ http://issues.apache.org/jira/browse/DERBY-1559?page=all ]
Andreas Korneliussen updated DERBY-1559:
----------------------------------------
Fix Version/s: 10.3.0.0
Derby Info: (was: [Patch Available])
Committed revision 438478 at trunk.
> 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
> Fix For: 10.3.0.0
>
> Attachments: DERBY-1559.diff, DERBY-1559.stat, DERBY-1559v2.diff,
> DERBY-1559v3.diff, DERBY-1559v4.diff, DERBY-1559v5.diff, DERBY-1559v6.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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