What are the three steps you should take to tune a JDBC Connection pool in WebLogic from the
initial settings in a production environment?
A.
Ensure the maximum size is increased to an appropriate setting.
B.
Set the minimum and maximum size of the connection pool to the same value.
C.
Increase the statement cache size.
D.
Add more heap to the JVM.
E.
Add more nodes to the cluster.
Explanation:
A:
* Troubleshooting Slow Response Time from the Client and Low Database Usage
These symptoms are usually caused by a bottleneck upstream of the database, perhaps in the
JDBC connectionpooling. Monitor the active JDBC connections in the WebLogic Console and
watch for excessive waiters and wait times; increase the pool size, if necessary.
* Attribute: Maximum Capacity
Maximum number of physical database connections that this connection pool can contain.
Different JDBC Drivers and database servers may limit the number of possible physical
connections.C: Attribute: Statement Cache Size
The algorithm used to maintain the statement cache:
LRU – After the statementCacheSize is met, the Least Recently Used statement is removed when
a new statement is used.
Fixed – The first statementCacheSize number of statements is stored and stay fixed in the cache.
No new statements are cached unless the cache is manually cleared.
E: If the queue appears starved but adding execute threads does not improve performance,
there may be resource contention. Because CPU utilization is low, the threads are probably
spending much of their time waiting for some resource, quite often a database connection.
Use the JDBC monitoring facilities in the console to check for high levels of waiters or long
wait times. Adding connections to the JDBC connection pool may be all that is required to
fix the problem.
Note:
* If you had a JDBC connection pool where the Initial Capacity and Maximum Capacity attributes
were different, you might want to create a gauge monitor to monitor the maximum and minimum
number of connections.
By setting the Threshold Low value to be one less than the Initial Capacity, your gauge monitor
trapcould monitor the ActiveConnectionsCurrentCount attribute of the JDBCDataSourceRuntime
MBean and alert you whenever the number of active connections are less than the Initial Capacity
(which might indicate database connectivity problems).
ABC
Not E, because adding nodes does not have any benefits for JDBC Connection Pools.
I also feel ‘E’ should not be answer in respect to question which has been asked, Question specifically talking about tunning JDBC configuration, not increasing capacity of domain, so ‘E’ should not be selected.
However, who know oracle person who wrote this question certified ‘E’ option as well thinking increasing another node will boost the database connectivity.
I will go with ‘ABC’ option in exam.
ABC
Initial capacity should be maximum.
http://docs.oracle.com/cd/E13222_01/wls/docs81/perform/WLSTuning.html#1123237
ABC let’s get it straight, it talks about configuring/tuning the JDBC connection pool not your JVM or Cluster
ABC
ABE
Before nothing is wrong writed:
Is maximum capacity not size.
A,C it’s perfect,
D, E are more scale than tunning
I would say B because is good idea dont waste time to create connections to database if you know how many connections you need.
http://docs.oracle.com/cd/E13222_01/wls/docs81/perform/WLSTuning.html#1123237
My final answer is A, B and C