Achilleas Achix

just try, but I'd bet my money that you need to tweak some things.

Hello dear forum!

Back with Jboss-6.0.0.Final we had the following data-source/pool definition :
<datasources> <xa-datasource> <jndi-name>pgsql</jndi-name> <track-connection-by-tx>true</track-connection-by-tx> <xa-datasource-class>org.postgresql.xa.PGXADataSource</xa-datasource-class> <xa-datasource-property name="ServerName">localhost</xa-datasource-property> <xa-datasource-property name="PortNumber">5432</xa-datasource-property> <xa-datasource-property name="DatabaseName">somedb</xa-datasource-property> <security-domain>postgresqluser</security-domain> <min-pool-size>0</min-pool-size> <max-pool-size>5</max-pool-size> </xa-datasource> </datasources>
The definition for security-domain postgresqluser was:
<application-policy name="postgresqluser"> <authentication> <login-module code="org.jboss.resource.security.CallerIdentityLoginModule" flag="required"> <module-option name = "managedConnectionFactoryName">jboss.jca:service=XATxCM,name=pgsql</module-option> </login-module> </authentication> </application-policy>
So this gave us one pool per user with max size 5 (5 is the most that app requires + 1). If one user abused the system, and try to get more than 5 connections (e.g by pressing F5 quickly) the rest of users were unaffected since all he/she could do was to block waiting for more connections.

Now we migrated the above configuration to wildfly-10.1.0.Final as follows :
<xa-datasource jndi-name="java:/pgsql" pool-name="smaDS" enabled="true" use-ccm="true" mcp="org.jboss.jca.core.connectionmanager.pool.mcp.LeakDumperManagedConnectionPool" statistics-enabled="true"> <xa-datasource-class>org.postgresql.xa.PGXADataSource</xa-datasource-class> <xa-datasource-property name="PortNumber">5432</xa-datasource-property> <xa-datasource-property name="DatabaseName">somedb</xa-datasource-property> <xa-datasource-property name="ServerName">localhost</xa-datasource-property> <xa-datasource-class>org.postgresql.xa.PGXADataSource</xa-datasource-class> <driver>postgresql-9.4.1212.jar</driver> <xa-pool> <min-pool-size>0</min-pool-size> <initial-pool-size>0</initial-pool-size> <max-pool-size>5</max-pool-size> <allow-multiple-users>true</allow-multiple-users> <wrap-xa-resource>true</wrap-xa-resource> </xa-pool> <security> <security-domain>postgresqluser</security-domain> </security> </xa-datasource> <security-domain name="postgresqluser"> <authentication> <login-module code="org.picketbox.datasource.security.CallerIdentityLoginModule" flag="required"> <module-option name="password-stacking" value="useFirstPass"/> <module-option name="managedConnectionFactoryName" value="name=pgsql,jboss.jca:service=XATxCM"/> </login-module> </authentication> </security-domain>

The behavior we have witnessed is different, it seems that wildfly gives the first user his 5 connections, who is able to work as long as no other user logs into the system. When the second users logs in, it seems to give to him his 5 connections (by looking into postgresql activity and logs) but it doesn't seem to be able to do any work with all 10 connections at the same time, then the second user gets blocked or some connection attempts of the first user get blocked as well. By specifying max-pool-size=10 in wildfly seems to be able to handle the first two users successfully. I know (by looking at the logs) the default pool in wildfly uses strategy : org.jboss.jca.core.connectionmanager.pool.strategy.PoolBySubjectAndCri . So I guess now in wildfly subpools' semantics have been changed to meaning partitioning of the same single pool, instead of multiple pool instances as used to be the case in jboss-6.0.0.Final.

Is my understanding correct? And if yes, which means max-pool-size applies to the whole pool, then is there a way to limit connections per user? (I know we could limit the users at the database layer, but we would like to be able to replicate the old behavior, before we move on to new changes).

Rahul Sudip Bose wrote:They finally replied. But they say that it can take 6-7 weeks more !!! I am wondering if i should make a new post for this ?

relax, you do have the printout of the exam, haven't you? So its all good. Did you check your record in Prometric's site?

You should try 6.0.0-Final. In case this is a bug in 5.1, 6.* has bigger chances of being supported.
Needless to say, jboss "open source-like" community, i hate to say. I have been living with Postgresql and jboss for over 10 years, and the gap between the one "open source" and the other is just huge.

I had several thoughts/issues/etc with jboss, my posts over the forums got 1000s views but zero answers. On the postgresql camp, things are totally different, luckily!

Rahul Sudip Bose wrote:I could not access my account because they were moving their database. I gave all relevant exam-info to them (by mail) and no reply even well after 5 business days. Now what ?

i think they told me to wait till end of June. But they were very helpful and replied very fast.

Miltos Deligiannis wrote:

Stephan van Hulst wrote:If you want to restore the value of a static variable between sessions, you are responsible for saving the value yourself, and loading it when the class is initialized.

Ok so, for each of the 3 Dog objects you save manually each one's value for the static var, right? But when deserialized at the same time only one Class dog is loaded whose static var needs a value. which of the 3 (one per object)?

Milto, γιά σου και καλή τύχη με τις εξετάσεις

To your question, the static var apparently will take the value of the last object deserialized.

kri shan wrote:Let me know the price

oops sorry it took me so late to answer.
How about 15 euros?

Ikpefua Jacob-Obinyan wrote:@Andreas...I have just CONFIRMED my exams for Monday June 20...So I will sort of coordinate myself with you, it is the 5th time I am going through the K & B book, I will be through on Friday and do mock tests Saturday and Sunday, Then Monday I will go there and get-the-job-done...Wish me luck!...

Guys, in addition to what my friend Ikpefua wrote, something that the book does not explicitly say:

Compiler prefers : WIDENING then BOXING then VARARGS -- INDIVIDUALLY NOT COMBINATION

Varargs works as a last "catchall" resort.

Compiler CANNOT widen then box

Compiler CAN box/unbox then widen

Ikpefua

I have written notes on each one of the 9 chapters + one additional of mine + over 140 programs. If you are interested i can send it all over.

Ashish Agre wrote:Congrats brother
well i also passed the exam. Tell me how to insert name in SCJP Wall Of Fame!

you too man!

Ikpefua Jacob-Obinyan wrote:@Achilleas...Thanks man that was the idea I had all along and thats what I did:

public String toString(){ return height + " " + width + " "+ origin.x + " " + origin.y + " "; }

Now I got confused when @Hama said;

but it should be either rectOne or rectTwo

So I was wondering if there was a way 'rectOne' or 'rectTwo' could display as output.

rectone is the name of the variable. There is no way in java for an Object to know the name of the variable which points to (refers to) it!!!

MAN!!! You just gave a GREAT idea!!! An Object to know the name and type of the variable it is pointed to. Or to be more specific a list of all variables which point to it!!

Ikpefua, Rectangle has only height, width and point. You have to use ONLY those in your toString() method.
Why would you want to employ more than 1 Rectangle instances?
IMOH here:
public int isLargerThan(Relatable other) { Rectangle otherRect = (Rectangle)other; if (this.getArea() < otherRect.getArea()) return -1; else if (this.getArea() > otherRect.getArea()) return 1; else return 0; } public Object findLargest(Object object1, Object object2) { Relatable obj1 = (Relatable)object1; Relatable obj2 = (Relatable)object2; if ( (obj1).isLargerThan(obj2) > 0) return object1; else return object2; }

- the cast Rectangle otherRect = (Rectangle)other; is not needed.
- public Object findLargest(Object object1, Object object2) could very well be static
- public Object findLargest(Object object1, Object object2) could very well have a signature of findLargest(Rectangle object1, Rectangle object2) , no point in having arguments of type Object.

Boris Mechkov wrote:Congrats man! I am scheduling mine for the end of June...I am getting worried now...
By the way, are the practice questions/exams from K&B book more difficult, equally or less difficult than the real exam?
Thanks man!

No need to worry!
The key point is to write many programs, (i wrote 145 of them), but not just write them and run them. NO!, you must document every conclusion that your programs lead you to do, on paper! (or file!) You must do it in a systematic way. Don't get fooled that the book has it all. No. The book is brilliant, its style is awesome, i like it very much, but yet you need to keep your own notes.

PS
Are you from Russia/Bulgaria?

Finally i ordered this one :

Joe Harry wrote:Congrats!

Danke!