Hello,
I have the problem that the Tomcat connection pool uses more than the maxActive
connections. In my Dropwizard application I have configured a maxSize of 30,
but I found the following message in the logs.
Timeout: Pool empty. Unable to fetch a connection in 15 seconds, none
available[size:31; busy:31; idle:0; lastwait:15000]
This seems to be related to a high pressure on the DB. In the DB logs I also
found some connection issues
The code in the PooledConnection class does not seem to be completely
bulletproof, because there can't be only two threads that have gone through the
first if-two, or am I wrong?
//if we get here, see if we need to create one
//this is not 100% accurate since it doesn't use a shared
//atomic variable - a connection can become idle while we are creating
//a new connection
if (size.get() < getPoolProperties().getMaxActive()) {
//atomic duplicate check
if (size.addAndGet(1) > getPoolProperties().getMaxActive()) {
//if we got here, two threads passed through the first if
size.decrementAndGet();
} else {
//create a connection, we're below the limit
return createConnection(now, con, username, password);
}
} //end if
In the end, this problem causes all my available DB connections to be used up
and my application to fail.
Is this a known problem? Is there a workaround?
Thanks for your answers,
Regards Stefan
Stefan López Romero
Senior Lead IT Architect
Theresienhöhe 13, 80339 München
stefan.lo...@maibornwolff.de
+49 151 544 22 050
[cid:image149c85.PNG@ee2dc33c.41920058]<https://www.maibornwolff.de/>
MaibornWolff GmbH
Theresienhöhe 13, 80339 München
www.maibornwolff.de
Telefon +49 89 544 253 000
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