Andreas Korneliussen wrote:
Kathey Marsden wrote:
Tomohito Nakayama (JIRA) wrote:
[
http://issues.apache.org/jira/browse/DERBY-550?page=comments#action_12419714
]
Tomohito Nakayama commented on DERBY-550:
-----------------------------------------
I intended to resolve this issue as "Cannot Reproduce" as next url.
http://issues.apache.org/jira/browse/DERBY-1472#action_12419712
However, I reconsidered.
I won't resolve DERBY-550, "BLOB : java.lang.OutOfMemoryError with
network JDBC driver (org.apache.derby.jdbc.ClientDriver)",
because it seems to be true that OutOfMemoryError happens "in server
side".
Title of DERBY-550 does not say that Error happens in client side.
Then, this issue is not mistaken completely.
Description of the issue "writting all the file into memory (RAM)
before sending ", is mistaken.
Sorry for my own propagation of confusion over this issue. When
filing DERBY-326 and seeing similar code in the client I suspected
there might be streaming issues in the client as well. I then took
DERBY-550 as confirmation of that when I saw it filed against the
client and described in this way.
In addition to changing the component to Network Server, changing the
DERBY-550 description as follows might clarify things sufficiently.
from
"Using the org.apache.derby.jdbc.ClientDriver driver to access the
Derby database through network, the driver is writting all the file
into memory (RAM) before sending
it to the database. "
to more of a a description of the functional problem:
"Using the org.apache.derby.jdbc.ClientDriver driver to access the
Derby database through network, sending a large amount of parameter
data with setBinaryStream will cause Network Server to throw an
OutOfMemoryException.
I am not sure if setCharacterStream is also at issue. If so it could
be filed as a separate issue.
I think additionally one could make an issue for the client:
"Using the org.apache.derby.jdbc.ClientDriver driver to access the Derby
database through network, receiving a large amount of resultset data
with rs.next() may cause Network Client to go out of memory"
I think derby works fine in the "sending" end of the streams, however in
the receiving end, there are memory problems.
I can second that, as I had a look at the code for ResultSet when
looking at another issue. For instance, the
NetCursor.getBlobColumn-method seems to materialize the whole Blob:
(data is a byte array)
if (data != null) {
// data found
// set data offset based on the presence of a null indicator
if (!nullable_[index]) {
dataOffset = 0;
} else {
dataOffset = 1;
}
blob = new Blob(data, agent, dataOffset);
} else {
The contents of 'data' come from the copyEXTDTA-method in
NetStatementReply.java.
protected void copyEXTDTA(NetCursor netCursor) throws
DisconnectException {
try {
parseLengthAndMatchCodePoint(CodePoint.EXTDTA);
byte[] data = null;
if (longValueForDecryption_ == null) {
data = (getData(null)).toByteArray();
} else {
data = longValueForDecryption_;
dssLength_ = 0;
longValueForDecryption_ = null;
}
netCursor.extdtaData_.add(data);
} catch (java.lang.OutOfMemoryError e) {
agent_.accumulateChainBreakingReadExceptionAndThrow(new
DisconnectException(agent_,
new
ClientMessageId(SQLState.NET_LOB_DATA_TOO_LARGE_FOR_JVM),
e));
}
}
I know layerB streaming in DRDA is not yet implemented (DERBY-1471) for
streaming from the client to the server (to be used for streams with
unknown length).
Do we have any support for streaming between server and client, which
could be used to implement LOB streaming?
Do we support streaming in the embedded driver?
--
Kristian
Andreas
