JDBC DATASOURCE ISSUES:
Many times we may encounter Datasource overlosd issues.
At those times you may track below kind of errors in logs.
<BEA-001129> <Received exception while creating connection for pool "ARS213NotificDBConn": Cannot open database "ARS271TEST" requested by the login. The login failed. ClientConnectionId:5c6a702b-00ad-4d38-b031-2645f4a89563.>
<Mar 5, 2013 5:32:34 AM GMT> <Error> <JDBC> <BEA-001112> <Test "SELECT 1" set up for pool "SFA316NytificDBConn" failed with exception: "com.microsoft.sqlserver.jdbc.SQLServerException: Connection reset".>
<Mar 5, 2013 5:32:35 AM GMT> <Error> <JDBC> <BEA-001112> <Test "SELECT 1" set up for pool "SFA271ARDBConn" failed with exception: "com.microsoft.sqlserver.jdbc.SQLServerException: Connection reset".>
<Mar 5, 2013 5:32:45 AM GMT> <Error> <JDBC> <BEA-001112> <Test "SELECT 1" set up for pool "SFA315HeldDBConn" failed with exception: "com.microsoft.sqlserver.jdbc.SQLServerException: Connection reset".>
<Mar 5, 2013 5:32:52 AM GMT> <Error> <JDBC> <BEA-001112> <Test "SELECT 1" set up for pool "SFA316ARDBConn" failed with exception: "com.microsoft.sqlserver.jdbc.SQLServerException: Connection reset".>
<Mar 5, 2013 5:33:07 AM GMT> <Error> <JDBC> <BEA-001112> <Test "SELECT 1" set up for pool "SFA319ARDBConn" failed with exception: "com.microsoft.sqlserver.jdbc.SQLServerException: Connection reset".>
ERROR:
weblogic.common.resourcepool.ResourceDisabledException:
Pool SFA213HeldDBConn is Suspended, cannot allocate resources to applications.
Immediate Resolution:
login to your weblogic console:
left pane click on services->datasources->click on the datasource->control tab
Clear the statement cache / shutdown & start the datasource:
After the immdiate action lets now look at how we can avoid this reoccurance :
JDBC TIPS AND KNOWLEDGE:
Tuning JDBC Conne
ction Pool Initial Capacity
The
InitialCapacity attribute of the
JDBCConnectionPool
element enables you to set the number of physical database connections
to create when configuring the pool. If the server cannot create this
number of connections, the creation of this connection pool will fail.
During development, it may be convenient to set the value of the
InitialCapacity attribute to a low number to help the server start up faster. In production systems, consider setting the
InitialCapacity value equal to the
MaxCapacity
attribute's default production mode setting of 25. This way, all
database connections are acquired during server start-up. And if you
need to tune the
MaxCapacity value, make sure to set the
InitialCapacity so that it equals the
MaxCapacity value.
If
InitialCapacity is less than
MaxCapacity,
the server needs to create additional database connections when its
load is increased. When the server is under load, all resources should
be working to complete requests as fast as possible, rather than
creating new database connections.
Tuning JDBC Connection Pool Maximum Capacity
The
MaxCapacity attribute of the
JDBCConnectionPool
element allows you to set the maximum number of physical database
connections that a connection pool can contain. Different JDBC drivers
and database servers might limit the number of possible physical
connections.
The default settings for development and
production mode are equal to the default number of execute threads: 15
for development mode; 25 for production mode. However, in production, it
is advisable that the number of connections in the pool equal the
number of concurrent client sessions that require JDBC connections. The
pool capacity is independent of the number of execute threads in the
server. There may be many more ongoing user sessions than there are
execute threads.
However in WEblogic 8:
It was adviced to Set the Maximum Capacity of the connection pool at least equal to the Execute Thread Count.
From
WLS 9.0 series onwards,server has a single thread pool for requests
from all applications. Similarly, all pending work is enqueued in a
common priority-based queue. The thread count is automatically tuned to
achieve maximum overall throughput.
One of the major differences between execute queues and the new
thread scheduling model is that the thread count does not need to be
set. In earlier releases, customers defined new thread pools and
configured their size to avoid deadlocks and provide differentiated
service. It is quite difficult to determine the exact number of threads
needed in production to achieve optimal throughput and avoid deadlocks.
WebLogic Server 9.0 is self-tuned, dynamically adjusting the number of
threads to avoid deadlocks and achieve optimal throughput subject to
concurrency constraints.
The maximum threads constraint can be used to limit the maximum
number of concurrent threads given to all WorkManagers that share the
constraint.This constraint should be used in very special cases and
should not be confused with the thread count parameter in execute
queues. The minimum threads constraint takes an integer value that
specifies the number of threads that should be assigned to this
constraint to prevent server-to-server deadlocks. | | | | | | | |
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There
is no Execute Queue concept from Weblogic server 9 version onwards.They
have intoduced WORK MANAGERS instead of that.Now WebLogic Server uses a
single thread pool, in which all types of work are executed. WebLogic
Server prioritizes work based on rules you define, and run-time metrics,
including the actual time it takes to execute a request and the rate at
which requests are entering and leaving the pool.
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Test Connections On Reserve(do not check)
Enables WebLogic Server to test a connection before giving it to a client. (Requires that you specify a Test Table Name.)
The
test adds a small delay in serving the client's request for a
connection from the pool, but ensures that the client receives a viable
connection.
MBean Attribute (Does not apply to application modules) :
JDBCConnectionPoolParamsBean.TestConnectionsOnReserve
Statement Cache Size(SET to 10)
The number of prepared and callable statements stored in the cache. (This may increase server performance.)
WebLogic
Server can reuse statements in the cache without reloading the
statements, which can increase server performance. Each connection in
the connection pool has its own cache of statements.
Setting the size of the statement cache to 0 turns off statement caching.
MBean Attribute (Does not apply to application modules) :
JDBCConnectionPoolParamsBean.StatementCacheSize
Minimum value:
0
Maximum value:
1024
When using DataSource objects for a connection pool, use the Honors Global Transaction option to create a TxDataSource.
The only time you should use a non-Tx Data Source is when you want to
do some work on the database that you do not want to include in the
current transaction.
When configuring a connection pool to use with WebLogic JMS JDBC Store, use non-XA database drivers.
