While looking in to application undeployment issue, I noticed that
*getApplications*() in ApplicationHolder is executed as a synchronized
block. Normally doing IO operations inside a synchronized block is not
recommended since other threads has to wait to take the lock. Assume that
one thread hang a long time due to a slowness in just one connection of
registry db call, then all other threads become BLOCKED. This may result in
performance degrade.
I guess since it is just a READ operation, it is not needed to synchronize.
public static Applications getApplications () {
if (applications == null) {
synchronized (ApplicationHolder.class) {
if (applications == null) {
// retrieve from registry
applications = AutoscalerUtil.getApplications();
if (log.isDebugEnabled()) {
log.debug("Trying to retrieve Applications from
registry");
}
if (applications == null) {
if (log.isDebugEnabled()) {
log.debug("No applications found in Registry");
}
// create a new Applications object
applications = new Applications();
}
}
}
}
return applications;
}
--
Udara Liyanage
Software Engineer
WSO2, Inc.: http://wso2.com
lean. enterprise. middleware
web: http://udaraliyanage.wordpress.com
phone: +94 71 443 6897
