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2017/03/20

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Side effects of dfc.diagnostics.resources.enable

Assuming that I set correct credentials and we do know how to set dfc preferences in runtime, what does code below print?

@Test
public void test() throws Exception {
    int count = 0;
    try {
        DfPreferences preferences = DfPreferences.getInstance();
        preferences.loadProperty(DfPreferences.DFC_SESSION_MAX_COUNT, 50);
        while (++count > 0) {
            IDfClientX clientX = new DfClientX();
            IDfClient client = clientX.getLocalClient();
            IDfSessionManager sessionManager = client.newSessionManager();
            IDfLoginInfo loginInfo = clientX.getLoginInfo();
            loginInfo.setUser("dmadmin");
            loginInfo.setPassword("dmadmin");
            sessionManager.setIdentity("DCTM_DEV", loginInfo);
            IDfSession session = sessionManager.getSession("DCTM_DEV");
        }
    } finally {
        System.out.println("Session count: " + count);
    }
}

Actually, the answer is obvious – that buggy code creates 50 sessions and fails:

Session count: 50

DfServiceException:: THREAD: main; MSG: [DM_API_E_NO_SESSION]error:  "There are no more available sessions."
; ERRORCODE: 100; NEXT: null
	at com.documentum.fc.client.impl.connection.docbase.DocbaseConnectionManager.getConnectionFromPool(DocbaseConnectionManager.java:168)
	at com.documentum.fc.client.impl.connection.docbase.DocbaseConnectionManager.getDocbaseConnection(DocbaseConnectionManager.java:94)
	at com.documentum.fc.client.impl.session.SessionFactory.newSession(SessionFactory.java:23)
	at com.documentum.fc.client.impl.session.PrincipalAwareSessionFactory.newSession(PrincipalAwareSessionFactory.java:44)
	at com.documentum.fc.client.impl.session.PooledSessionFactory.newSession(PooledSessionFactory.java:49)
	at com.documentum.fc.client.impl.session.SessionManager.getSessionFromFactory(SessionManager.java:134)
	at com.documentum.fc.client.impl.session.SessionManager.newSession(SessionManager.java:72)
	at com.documentum.fc.client.impl.session.SessionManager.getSession(SessionManager.java:191)
	at SessionDemo.test(SessionDemo.java:30)

Now, less obvious code:

@Test
public void test() throws Exception {
    int count = 0;
    try {
        DfPreferences preferences = DfPreferences.getInstance();
        preferences.loadProperty(DfPreferences.DFC_SESSION_MAX_COUNT, 50);
        preferences.loadProperty(DfPreferences.DFC_DIAGNOSTICS_RESOURCES_ENABLE, true);
        while (++count > 0) {
            IDfClientX clientX = new DfClientX();
            IDfClient client = clientX.getLocalClient();
            IDfSessionManager sessionManager = client.newSessionManager();
            IDfLoginInfo loginInfo = clientX.getLoginInfo();
            loginInfo.setUser("dmadmin");
            loginInfo.setPassword("dmadmin");
            sessionManager.setIdentity("DCTM_DEV", loginInfo);
            IDfSession session = sessionManager.getSession("DCTM_DEV");
        }
    } finally {
        System.out.println("Session count: " + count);
    }
}

the result is bit confusing – code creates more than 50 sessions and fails:

...
25586 [Resource Housekeeper] ERROR com.documentum.fc.client.impl.session.StrongSessionHandle$DisposableData  - [DFC_SESSION_NOT_RELEASED] Unreleased session found during garbage collection, Session{id=29, iid=29, serial=1, docbase=DCTM_DEV, user=dmadmin, serversession=none}
com.documentum.fc.impl.util.ThrowableStack: Stack when session was obtained
	at SessionDemo.test(SessionDemo.java:31)
...

Session count: 94

DfServiceException:: THREAD: main; MSG: [DM_API_E_NO_SESSION]error:  "There are no more available sessions."
; ERRORCODE: 100; NEXT: null
	at com.documentum.fc.client.impl.connection.docbase.DocbaseConnectionManager.getConnectionFromPool(DocbaseConnectionManager.java:168)
	at com.documentum.fc.client.impl.connection.docbase.DocbaseConnectionManager.getDocbaseConnection(DocbaseConnectionManager.java:94)
	at com.documentum.fc.client.impl.session.SessionFactory.newSession(SessionFactory.java:23)
	at com.documentum.fc.client.impl.session.PrincipalAwareSessionFactory.newSession(PrincipalAwareSessionFactory.java:44)
	at com.documentum.fc.client.impl.session.PooledSessionFactory.newSession(PooledSessionFactory.java:49)
	at com.documentum.fc.client.impl.session.SessionManager.getSessionFromFactory(SessionManager.java:134)
	at com.documentum.fc.client.impl.session.SessionManager.newSession(SessionManager.java:72)
	at com.documentum.fc.client.impl.session.SessionManager.getSession(SessionManager.java:191)
	at SessionDemo.test(SessionDemo.java:31)

another code:

@Test
public void test() throws Exception {
    int count = 0;
    try {
        DfPreferences preferences = DfPreferences.getInstance();
        preferences.loadProperty(DfPreferences.DFC_SESSION_MAX_COUNT, 50);
        preferences.loadProperty(DfPreferences.DFC_DIAGNOSTICS_RESOURCES_ENABLE, true);
        while (++count > 0) {
            IDfClientX clientX = new DfClientX();
            IDfClient client = clientX.getLocalClient();
            IDfSessionManager sessionManager = client.newSessionManager();
            IDfLoginInfo loginInfo = clientX.getLoginInfo();
            loginInfo.setUser("dmadmin");
            loginInfo.setPassword("dmadmin");
            sessionManager.setIdentity("DCTM_DEV", loginInfo);
            IDfSession session = sessionManager.getSession("DCTM_DEV");
            System.gc();
        }
    } finally {
        System.out.println("Session count: " + count);
    }
}

the result is weird – code prints a lot of diagnostics messages but does not fail:

...
115902 [Resource Housekeeper] ERROR com.documentum.fc.client.impl.session.StrongSessionHandle$DisposableData  - [DFC_SESSION_NOT_RELEASED] Unreleased session found during garbage collection, Session{id=1, iid=1207, serial=1, docbase=DCTM_DEV, user=dmadmin, serversession=none}
com.documentum.fc.impl.util.ThrowableStack: Stack when session was obtained
	at SessionDemo.test(SessionDemo.java:31)
...

and the last example:

@Test
public void test() throws Exception {
    int count = 0;
    try {
        DfPreferences preferences = DfPreferences.getInstance();
        preferences.loadProperty(DfPreferences.DFC_SESSION_MAX_COUNT, 50);
        preferences.loadProperty(DfPreferences.DFC_DIAGNOSTICS_RESOURCES_ENABLE, true);
        while (++count > 0) {
            IDfClientX clientX = new DfClientX();
            IDfClient client = clientX.getLocalClient();
            IDfSessionManager sessionManager = client.newSessionManager();
            IDfLoginInfo loginInfo = clientX.getLoginInfo();
            loginInfo.setUser("dmadmin");
            loginInfo.setPassword("dmadmin");
            sessionManager.setIdentity("DCTM_DEV", loginInfo);
            IDfSession session = sessionManager.getSession("DCTM_DEV");
            session.beginTrans();
            System.gc();
        }
    } finally {
        System.out.println("Session count: " + count);
    }
}

result is even more weird – code does not print diagnostic messages and fails:

4964 [Resource Housekeeper] ERROR com.documentum.fc.client.impl.connection.docbase.DocbaseConnection  - Connection put back in pool with transaction active, Connection{id=1, docbase=DCTM_DEV, user=dmadmin, state=FREE}

Session count: 50

DfServiceException:: THREAD: main; MSG: [DM_API_E_NO_SESSION]error:  "There are no more available sessions."
; ERRORCODE: 100; NEXT: null
	at com.documentum.fc.client.impl.connection.docbase.DocbaseConnectionManager.getConnectionFromPool(DocbaseConnectionManager.java:168)
	at com.documentum.fc.client.impl.connection.docbase.DocbaseConnectionManager.getDocbaseConnection(DocbaseConnectionManager.java:94)
	at com.documentum.fc.client.impl.session.SessionFactory.newSession(SessionFactory.java:23)
	at com.documentum.fc.client.impl.session.PrincipalAwareSessionFactory.newSession(PrincipalAwareSessionFactory.java:44)
	at com.documentum.fc.client.impl.session.PooledSessionFactory.newSession(PooledSessionFactory.java:49)
	at com.documentum.fc.client.impl.session.SessionManager.getSessionFromFactory(SessionManager.java:134)
	at com.documentum.fc.client.impl.session.SessionManager.newSession(SessionManager.java:72)
	at com.documentum.fc.client.impl.session.SessionManager.getSession(SessionManager.java:191)
	at SessionDemo.test(SessionDemo.java:31)

Corresponding thread dump:

"Resource Housekeeper" #13 daemon prio=10 os_prio=31 tid=0x00007fb78c1bd800 nid=0x5703 in Object.wait() [0x0000700001452000]
   java.lang.Thread.State: TIMED_WAITING (on object monitor)
	at java.lang.Object.wait(Native Method)
	- waiting on <0x00000006c0dc9828> (a com.documentum.fc.client.impl.connection.docbase.DocbaseConnection)
	at com.documentum.fc.client.impl.connection.docbase.DocbaseConnection.waitForCorrectSharingContext(DocbaseConnection.java:820)
	- locked <0x00000006c0dc9828> (a com.documentum.fc.client.impl.connection.docbase.DocbaseConnection)
	at com.documentum.fc.client.impl.connection.docbase.DocbaseConnection.evaluateRpc(DocbaseConnection.java:1108)
	- locked <0x00000006c0dc9828> (a com.documentum.fc.client.impl.connection.docbase.DocbaseConnection)
	at com.documentum.fc.client.impl.connection.docbase.DocbaseConnection.applyForBool(DocbaseConnection.java:1198)
	- locked <0x00000006c0dc9828> (a com.documentum.fc.client.impl.connection.docbase.DocbaseConnection)
	at com.documentum.fc.client.impl.connection.docbase.DocbaseConnection.apply(DocbaseConnection.java:1183)
	at com.documentum.fc.client.impl.docbase.DocbaseApi.endTrans(DocbaseApi.java:1757)
	at com.documentum.fc.client.impl.connection.docbase.DocbaseConnection.cleanupFromUnexpectedTransactionState(DocbaseConnection.java:729)
	at com.documentum.fc.client.impl.connection.docbase.DocbaseConnection.quiesce(DocbaseConnection.java:663)
	- locked <0x00000006c0dc9828> (a com.documentum.fc.client.impl.connection.docbase.DocbaseConnection)
	at com.documentum.fc.client.impl.connection.docbase.DocbaseConnectionManager.returnConnectionToPool(DocbaseConnectionManager.java:663)
	at com.documentum.fc.client.impl.connection.docbase.DocbaseConnectionManager.release(DocbaseConnectionManager.java:270)
	at com.documentum.fc.client.impl.session.Session.releaseConnection(Session.java:248)
	at com.documentum.fc.client.impl.session.PooledSessionFactory$SessionListener.onDisconnect(PooledSessionFactory.java:114)
	at com.documentum.fc.client.impl.session.Session.notifyListenersOfDisconnect(Session.java:395)
	at com.documentum.fc.client.impl.session.Session.disconnect(Session.java:312)
	at com.documentum.fc.client.impl.session.Session.decrementReferenceCount(Session.java:3687)
	at com.documentum.fc.client.impl.session.StrongSessionHandle$DisposableData.dispose(StrongSessionHandle.java:127)
	at com.documentum.fc.internal.reshousekeeper.ResourceHousekeeper$1$1.run(ResourceHousekeeper.java:52)

Try to explain results 🙂

2 thoughts on “Side effects of dfc.diagnostics.resources.enable”

  1. umm, maybe gc() frees some sessionmanagers and “cut” the connection so there are still sessions available? Still weird that you can go over the session limit (maybe the diagnostics skip the limit?) Have you already decompiled the code to see what’s doing? I guess so 😀

    Like

  2. Pingback: Explanation for dfc.diagnostics.resources.enable | Documentum in a (nuts)HELL

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