/**
* Run the maintenance thread. Every REFRESH seconds, re-register this app server as alive in
* the cluster. Then check for any cluster entries that are more than EXPIRED seconds old,
* indicating a failed app server, and remove that record, that server's sessions, generating
* appropriate session events so the other app servers know what's going on. The "then" checks
* need not be done each iteration - run them on 1 of n randomly choosen iterations. In a
* clustered environment, this also distributes the work over the cluster better.
*/
public void run() {
// wait till things are rolling
ComponentManager.waitTillConfigured();
if (M_log.isDebugEnabled()) M_log.debug("run()");
while (!m_maintenanceCheckerStop) {
try {
final String serverIdInstance = m_serverConfigurationService.getServerIdInstance();
if (M_log.isDebugEnabled()) M_log.debug("checking...");
// if we have been closed, reopen!
String statement = clusterServiceSql.getReadServerSql();
Object[] fields = new Object[1];
fields[0] = serverIdInstance;
List results = m_sqlService.dbRead(statement, fields, null);
if (results.isEmpty()) {
M_log.warn(
"run(): server has been closed in cluster table, reopened: " + serverIdInstance);
statement = clusterServiceSql.getInsertServerSql();
fields[0] = serverIdInstance;
boolean ok = m_sqlService.dbWrite(statement, fields);
if (!ok) {
M_log.warn("start(): dbWrite failed");
}
}
// update our alive and well status
else {
// register that this app server is alive and well
statement = clusterServiceSql.getUpdateServerSql();
fields[0] = serverIdInstance;
boolean ok = m_sqlService.dbWrite(statement, fields);
if (!ok) {
M_log.warn("run(): dbWrite failed: " + statement);
}
}
// pick a random number, 0..99, to see if we want to do the full ghosting / cleanup
// activities now
int rand = (int) (Math.random() * 100.0);
if (rand < m_ghostingPercent) {
// get all expired open app servers not me
statement = clusterServiceSql.getListExpiredServers(m_expired);
// setup the fields to skip reading me!
fields[0] = serverIdInstance;
List instances = m_sqlService.dbRead(statement, fields, null);
// close any severs found to be expired
for (Iterator iInstances = instances.iterator(); iInstances.hasNext(); ) {
String serverId = (String) iInstances.next();
// close the server - delete the record
statement = clusterServiceSql.getDeleteServerSql();
fields[0] = serverId;
boolean ok = m_sqlService.dbWrite(statement, fields);
if (!ok) {
M_log.warn("run(): dbWrite failed: " + statement);
}
M_log.warn(
"run(): ghost-busting server: " + serverId + " from : " + serverIdInstance);
}
// Close all sessions left over from deleted servers.
int nbrClosed = m_usageSessionService.closeSessionsOnInvalidServers(getServers());
if ((nbrClosed > 0) && M_log.isInfoEnabled())
M_log.info("Closed " + nbrClosed + " orphaned usage session records");
// Delete any orphaned locks from closed or missing sessions.
statement = clusterServiceSql.getOrphanedLockSessionsSql();
List sessions = m_sqlService.dbRead(statement);
if (sessions.size() > 0) {
if (M_log.isInfoEnabled())
M_log.info(
"Found " + sessions.size() + " closed or deleted sessions in lock table");
statement = clusterServiceSql.getDeleteLocksSql();
for (Iterator iSessions = sessions.iterator(); iSessions.hasNext(); ) {
fields[0] = (String) iSessions.next();
boolean ok = m_sqlService.dbWrite(statement, fields);
if (!ok) {
M_log.warn("run(): dbWrite failed: " + statement);
}
}
}
}
} catch (Throwable e) {
M_log.warn("exception: ", e);
} finally {
// clear out any current access bindings
m_threadLocalManager.clear();
}
// cycle every REFRESH seconds
if (!m_maintenanceCheckerStop) {
try {
Thread.sleep(m_refresh * 1000L);
} catch (Exception ignore) {
}
}
}
if (M_log.isDebugEnabled()) M_log.debug("done");
}
