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From Mark Thomas <>
Subject Re: Apache Tomcat 8.0.0-RC1 release vote started
Date Fri, 02 Aug 2013 19:34:52 GMT
On 02/08/2013 21:17, Michael-O wrote:
> Am 2013-08-02 11:43, schrieb Mark Thomas:
>> Michael-O <> wrote:
>>> Am 2013-08-01 22:59, schrieb Mark Thomas:
>>>> If you'd like early sight of Tomcat 8 and an opportunity to
>>> contribute
>>>> to Tomcat development, the release vote has now opened for the first
>>>> Tomcat 8 release candidate.
>>>> Features include:
>>>> -[...]
>>>> - Update to DBCP2 (now includes JMX monitoring)
>>>                ^^^^^
>>> Why if we do have the wonderful Tomcat JDBC Pool?
>> 1. Choice (we ship both).
>> 2. Features (DBCP covers more edge cases).
>> 3. Maintainability. There is more chance of a DBCP fix at the moment.
>> That should change when Filip returns.
>> 4. Performance they should be much closer but I suspect Tomcat JDBC
>> will be faster (those edge cases again).
> According to Apache's JIRA DBCP2 is still in the works

The bulk of the work was in Pool 2 and that has been complete for a
while. There are some discussions about further simplification of the
Pool 2 API but the core pooling code is ready and is unlikely to change.

The work to convert DBCP to use Pool 2 has been completed. DBCP
currently has a number of open bugs and enhancement requests and that is
holding up a formal release as a number of them are likely to trigger
API changes both in Pool 2 and DBCP 2.

In short, the core of DBCP2 is ready to go but the API is not stable.
Getting it into the Tomcat 8 RC's is part of getting feedback to help
stablise the API.

> whereas Tomcat
> JDBC Pool already works quite well.

For some users yes. As I said previously, it does not cover as many edge
cases as DBCP does.

> If so, I would favor the first
> option and make Tomcat JDBC Pool the default. Anyway DBCP2 will be a
> breaking change for DBCP 1.x users.

What makes you say that? I can't think of any configuration changes in
DBCP2 so far that would cause breakage (although I could be wrong).

> Why not go the extra mile with
> Tomcat JDBC Pool and use that.

It is (still) a one line configuration change to switch between the two.

Personally, I'm not happy with JDBC Pool as the default - primarily
because it is essentially supported by a single committer. It hasn't
built up a development community yet. DBCP has that development
community and is less dependent on a single committer.

>>> Can't we get rid of that relic?
>> We could but I would not support such a move.  (Relic? Hardly.)
> I consinder it as a relic. Tomcat JDBC Pool's site even states that DBCP
> was written in ancient times withou multithreading in mind. Pre Java 5
> and so forth.

That is true of DBCP 1. It does not apply to DBCP 2.

> From my point of view, I have achieved tremendous improvements in our
> apps with Tomcat JDBC Pool and even found several bugs which would not
> have been possible with DBCP.

Great. You are free to continue using it. It will continue to be part of
Tomcat 8 in the same way it is part of Tomcat 7. Getting those same
performance improvements for users that need / want DBCP is a primary
driver for Pool 2 and DBCP 2.

Ultimately, I'd like to see the code bases converge but that is probably
an optimistic goal for a number of reasons.


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