Server returns data when it receives a QRYROWSET value of zero on an OPNQRY,
which doesn't follow DRDA protocol.
----------------------------------------------------------------------------------------------------------------
Key: DERBY-1468
URL: http://issues.apache.org/jira/browse/DERBY-1468
Project: Derby
Type: Bug
Components: Network Server
Versions: 10.2.0.0
Reporter: A B
When a client sends a QRYROWSET value of zero to the server, DRDA indicates
that the server should not return any rows. But the current Derby Server
treats a qryrowset value of 0 (zero) the same as it does a value of 1 (one) and
thus performs pre-fetching (as of DERBY-822), which it shouldn't do.
As a result, clients that send a QRYROWSET of 0 and do not expect data could
see unexpected results--for example, the DB2 ODBC driver will return the first
row of data twice for scrollable cursors because of this issue.
Relevant discussion:
http://article.gmane.org/gmane.comp.apache.db.derby.devel/22659
Some quotes from DRDA manuals:
1) DRDA Manual v3 for OPNQRY:
The qryrowset parameter specifies whether a rowset of rows is to be returned
with the command. This is only honored for non-dynamic scrollable cursors
(QRYATTSNS not equal to QRYSNSDYN) and for non-scrollable cursors conforming to
the limited block query protocol. The target server fetches no more than the
requested number of rows. It may fetch fewer rows if it is restricted by extra
query block limits, or if a fetch operation results in a negative SQLSTATE or
an SQLSTATE of 02000.
2) Page 698 of V.3 says:
A QRYROWSET value of zero on the OPNQRY and EXCSQLSTT commands instructs the
server to return no rows with the OPNQRYRM for the cursor or result set. A
QRYROWSET value of zero on the CNTQRY command is invalid for non-rowset cursors
and results in the application server generating a SYNTAXRM with a SYNERRCD
value of '15'x (reserved value not allowed).
--
This message is automatically generated by JIRA.
-
If you think it was sent incorrectly contact one of the administrators:
http://issues.apache.org/jira/secure/Administrators.jspa
-
For more information on JIRA, see:
http://www.atlassian.com/software/jira
