Re: BasicDataSource restart()

[Mark Eggers]

Jerry,

On 11/30/2021 10:06 PM, Jerry Malcolm wrote:

I'm circling back to this after a few months.  I am building on a Windows 10 box with 9.0.52 TC.  But I'm running on an AWS Linux2 with 8.5.72.  This has never caused any problems so far, or at least as far as I can tell.  But I'm hitting something strange with this relatively new BasicDataSource.restart() method.   My reference to restart() builds fine.  But when I run it on the 8.5.72 server I get: java.lang.NoSuchMethodError: 'void org.apache.tomcat.dbcp.dbcp2.BasicDataSource.restart()'

Thx as always.

Jerry


On 9/7/2021 2:49 PM, Jerry Malcolm wrote:

Rémy mentioned that it should be in TC 8.5.58+.   This is a relatively clean EC2 on AWS, not running much other than Tomcat. And I have not done in backdoor (non yum) installs of TC that might have left old jar files around.   I noticed that there are 2 dbcp2 jar files in TC's lib. One is from the java install.  But the error message above is a tomcat path.  So I'm assuming it's tomcat's dbcp2 jar that's being referenced. I exploded the jar hoping there would be some version numbers somewhere inside telling me if I somehow have a backlevel jar.  But I couldn't find anything.  All I know is it's date is 2/25/2021 and it's 286,358 bytes. Any other ideas come to mind why it's telling me the restart() method doesn't exist?

On 9/7/2021 2:35 PM, Christopher Schultz wrote:

Jerry, Rémy,

On 9/3/21 07:15, Rémy Maucherat wrote:

On Fri, Sep 3, 2021 at 2:46 AM Jerry Malcolm <techst...@malcolms.com> wrote:

I have a requirement to start a new log database on the first of every

do not want to create a bunch of hardcoded manually configured

solution that is completely implemented and working except for one
little thing.


have an algorithm that substitutes yyyy_MM at the appropriate spot in
the configured URL and then updates the url in the datasource. All of

point to one database at a time.  My concern is that once I transition

already attached to the old database.  I need to clear those out and


The apache commons BasicDataSource has a restart() method. But

close() method on the BasicDataSource.  But I don't see anything that

and waiting for it to drain, then setting it back to the original

method, is there any other way to force all existing connections to
close and start clean?

month.  I still need to have access to older monthly log databases.   I individual datasources, one for each month.  I have a dynamic datasource I access the BasicDataSource implementation class for the datasource.  I this works great.  I can live with the fact that the datasource can only to another database, there are existing connections in the pool that are start over.  But I don't have the luxury of bouncing tomcat to clean it up. unfortunately that method is omitted from the Tomcat version. There is a will re-open it after closing.  I thought about changing maxActive to 0, value.  None of these sound like an ideal solution.  Without a restart()

The code is kept in sync with DBCP (with a bit of lag maybe), so these
lifecycle methods were also added to Tomcat one year ago (9.0.38+ and
8.5.58+).

  try
  {
      Context ctx = new InitialContext();

      DataSource ds = (DataSource)ctx.lookup(getJNDIPath());

      if(null == ds)
          throw new ServiceException("Cannot obtain DataSource");



          return call(ds, "restart");
      }
  } catch (Exception e) {

  }



As Rémy points out, it requires a Tomcat version 9.0.38+ or 8.5.58+.

Hope that helps,
-chris

We are using this at $work to bounce our database connection pools after TLS client certificate changes. This is the code we are using to reload the pool:       if(isInstanceOf(ds, "org.apache.tomcat.dbcp.dbcp2.BasicDataSource")          || isInstanceOf(ds, "org.apache.commons.dbcp2.BasicDataSource")) { org.apache.log4j.Logger.getLogger(this.getClass()).error("Failed to reload DataSource " + getJNDIPath()); The call() method simply encapsulates all of the work to make a reflective method call to BasicDataSource.restart().

Chris,



Thx

Jerry

I'll definitely try this.  But I'm curious about the restart method. Is it some sort of a hidden method that's only available to reflection?  Seems it would be a lot more straightforward to just make the restart method public like it is in the apache version of BasicDataSource.  I'm not complaining.  If this works, then fine. Just curious.

I haven't been following this thread, so I may be way off.





I raised the issue with AWS, and got silence back.



Could you be experiencing some similar issue?

. . . just a random thought
/mde/

The last time I used an AWS EC2 instance "out of the box" with an AWS-supplied Tomcat, I ran into some very strange behavior. It turns out that AWS packaged the 8.5.x Tomcat with the older (7.0.x) resource pool. I figured this out by looking at logs and seeing the complaints about my context.xml. Ever since then, I package up my own version of Tomcat using releases from tomcat.apache.org.

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