This is a seemingly pointless change. The RW-lock code is 100%
correct (afaict), yet we've seen repeated cases of test runs
hanging in JMX query because this lock is seemingly left held
by what seems to be the reaper task.
There is no explanation for this, no sign of exceptions/errors
that could explain the lock being broken. Nor any known JDK/JVM
bugs.
Yet, in tests, it seems that replacing the lock with a more
coarse, yet proven, synchronized, fixes the issue. So there.
I officially hate this patch, and it should not exist.
Before we were discarding the initial repository while
overriding it with TableRepository. This was a mistake that
caused dtests to fail. Proper solution is to keep the initial
repository inside TableRepository. That way whatever was registered
at the time of JmxMBeanServer creation is still handled properly.
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
Message-Id: <22181859012fd20ddf37e049a145bc94a3a91a33.1527844328.git.piotr@scylladb.com>
Default implementation stores MBeans in the following map:
<domain name> -> (<properties as a single string> -> NamedObject)
This is problematic because NamedObject contains ObjectName that
has both domain and properties inside itself.
This means we're storing the same data twice.
For domain "" we want to store MBeans in a more compact way using map:
ObjectName -> DynamicMBean
which is equivalent to NamedObject.
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
JmxMBeanServer is a concrete implementation of a MBeanServer.
We want to use it directly because we need to bypass calls to
JmxMBeanServer.registerMBean and JmxMBeanServer.unregisterMBean.
They take ObjectName as parameter, copy it using
ObjectName.getInstance(ObjectName) and pass it to registerMBean
and unregisterMBean of JmxMBeanServer.getMBeanServerInterceptor().
We want to avoid this copy and pass the ObjectName argument directly
to JmxMBeanServer.getMBeanServerInterceptor().
To do that this patch:
1. changes all MBeanServer variables to JmxMBeanServer
2. creates JmxMBeanServer in APIBuilder making sure accessing
interceptors is allowed
3. makes sure that JmxMBeanServer.getMBeanServerInterceptor().registerMBean
is called wherever JmxMBeanServer.registerMBean was called
4. makes sure that JmxMBeanServer.getMBeanServerInterceptor().unregisterMBean
is called whenever JmxMBeanServer.unregisterMBean was called
Next patch will use different ObjectName implementation that will
use less memory and this patch is crucial because without it every ObjectName
is transformed with ObjectName.getInstance which turns the object into
a regular ObjectName.
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
The APIBuilder is an implementation for the MBeanServerBuilder that is
used to instantiate the APIMBeanServer as the platform MBeanServer.
Signed-off-by: Amnon Heiman <amnon@scylladb.com>
Andrea Cavalli
Pekka Enberg
Calle Wilund
Piotr Jastrzebski
elcallio
Amnon Heiman