[ http://issues.apache.org/jira/browse/DERBY-821?page=all ]
Knut Anders Hatlen updated DERBY-821:
-------------------------------------
Attachment: DERBY-821.diff
DERBY-821.stat
changes.html
I have attached a patch (DERBY-821.diff) which lets the client driver
take advantage of the possibility to have result sets implicitly
closed on the server. In many cases, this saves one round trip per
select operation.
Inspired by the thoroughness certain developers have shown lately, I
have also uploaded a document describing the most important parts of
the patch in the hope that it is useful for reviewers. See the
attached file "changes.html".
I have done some testing of the performance. With simple single-record
select operations, there seems to be a clear increase in
performance. Having test clients running transactions similar to this
one
(autocommit off)
ResultSet rs = ps.executeQuery();
rs.next();
int id = rs.getInt(1);
String text = rs.getString(2);
rs.close();
conn.commit();
the number of round trips per transaction was reduced from four to
three. The effect on the throughput depended very much on the number
of clients. With few (1-3) clients, the throughput increased by
24%. With more than 20 clients, the increase in throughput was between
5% and 7%.
Derbyall passed more or less cleanly. I had four failures:
- ConcurrentImplicitCreateSchema failed with timeouts
- dataSourcePermissions_net failed with shutdown exception in the
DerbyNet framework
- runtimeinfo failed because it had two active sessions instead of
one. Happened in both DerbyNet and DerbyNetClient
All of these failures are frequently seen in Ole's regression tests.
> Client driver: Implicitly close exhausted result sets on the server
> ---------------------------------------------------------------------
>
> Key: DERBY-821
> URL: http://issues.apache.org/jira/browse/DERBY-821
> Project: Derby
> Type: Improvement
> Components: Network Client, Network Server, Performance
> Versions: 10.2.0.0
> Reporter: Knut Anders Hatlen
> Assignee: Knut Anders Hatlen
> Priority: Minor
> Fix For: 10.2.0.0
> Attachments: DERBY-821.diff, DERBY-821.stat, changes.html
>
> Forward-only result sets that are exhausted should be implicitly
> closed on the server. This way, ResultSet.close() does not have to
> send an explicit close message generating unnecessary network traffic.
> The DRDA protocol supports this. From the description of OPNQRY (open
> query):
> The qryclsimp parameter controls whether the target server
> implicitly closes a non-scrollable query upon end of data (SQLSTATE
> 02000) in association with the cursor type.
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