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# Deployments-->EJB --> Monitoring --> Entity EJBs

Run-Time Statistics for Entity EJBs Raw Monitoring Data for Entity EJBs Tasks Related Topics

## Overview

This page displays run-time statistics for entity EJBs in the currently selected archive. You can display statistics for one or more server instances on which the EJB is deployed. The statistics are defined in Run-Time Statistics for Entity EJBs.

You can tailor this console page to display some or all of the underlying counts from which the statistics are calculated, by clicking Customize this View, and selecting the desired data from the list of available columns. The available data is defined in Raw Monitoring Data for Entity EJBs.

The statistics and underlying counts reflect activity since the bean was last deployed.

## Run-Time Statistics for Entity EJBs

The following table defines the run-time statistics displayed for entity EJBs.

Table 91-1

Statistic | Description
--- | ---
Cache Miss Ratio | The cache miss ratio is a ratio of the number of times a container cannot find a bean in the cache (cache miss) to the number of times it attempts to find a bean in the cache (cache access). In general, the lower your cache miss ratio, the better your EJB will perform. The amount of time saved by getting a bean from the cache depends on the cost of the bean's `ejbActivate` method as well as the bean's cache-between-transactions setting. When a cache miss occurs, a bean must be obtained from the free pool and its ejbActivate method must be called. The more expensive it is to invoke `ejbActivate`, the more the cache miss will hurt performance. If the EJB is configured with cache-between-transactions set to true, the cache miss will also force the EJB container to make an extra call to the database to load the bean. For information on what to tune in response to the cache miss ratio statistic, see Cache Miss Ratio in the WebLogic Server Performance and Tuning Guide.
Lock Manager Waiter Ratio | This is the ratio of the number of times a thread had to wait to obtain a lock on a bean to the total amount of lock requests issued. For best performance, you want the lock waiter ratio to be as low as possible. For information on what to tune in response to the lock waiter ratio statistic, see Lock Waiter Ratio in the WebLogic Server Performance and Tuning Guide.
Lock Manager Timeout Ratio | This is the ratio of timeouts to accesses for the lock manager. Timeouts are very detrimental to performance and therefore, you should strive to keep your lock timeout ratio to an absolute minimum. Timeouts hurt performance on several levels. First, each thread waiting for a lock is one less thread that the server can be using to service other requests. Second, a lock timeout will result in an exception that will roll back the current transaction, erasing any work already done in the transaction and causing the current request to fail. For information on what to tune in response to the lock timeout ratio statistic, see Lock Timeout Ratio in the WebLogic Server Performance and Tuning Guide
Pool Miss Ratio | The pool miss ratio is a ratio of the number of times a request was made to get a bean from the pool when no beans were available, to the total number of requests for a bean made to the pool. The consequence of a pool miss is different for different types of beans. A pool miss for a stateless session bean will cause the requesting thread to wait for a bean to become available in the pool. The maximum time a thread will wait is equal to the transaction timeout value for the bean. Entity beans and message-driven beans will never wait for an instance to become available. Instead, a pool miss will cause the pool to create a new bean instance to service the request. Pool misses come at a cost since the executing thread will either have to wait for a bean to become available or have to wait for a new bean to be created. As such, it is best to try to keep your pool miss ratio to a minimum. For information on what to tune in response to the pool miss ratio statistic, see Pool Miss Ratio in the WebLogic Server Performance and Tuning Guide.
Destroyed Bean Ratio | The destroyed bean ratio is a ratio of the number of beans destroyed to the total number of requests for a bean. The EJB specification mandates that the EJB container destroys a bean when non-application exceptions are thrown from the bean during execution. Destroying beans comes at a cost, however, because destroyed beans will likely have to be replaced with new bean instances. As a result, you should keep your destroyed bean ratio to a minimum. For information on what to tune in response to the destroyed bean ratio statistic, see Destroyed Bean Ratio in the WebLogic Server Performance and Tuning Guide
Pool Timeout Ratio | The pool timeout ratio is a ratio of requests that have timed out waiting for a bean from the pool to the total number of requests made. This ratio is only valid for stateless session beans because it is the only type of bean that will wait for a bean to become available. Other types of beans will automatically create a new instance to service a request rather than waiting. For best performance, the pool timeout ratio should be as small as possible. For information on what to tune in response to the pool timeout ratio statistic, see Pool Timeout Ratio in the WebLogic Server Performance and Tuning Guide.
JMS Connection Alive | Reports whether the EJB container has successfully connected to the JMS destination source and that therefore the message-driven bean is receiving messages. If this field's value displays as `false`, check the server log for possible reasons for connection failure.
Transaction Rollback Ratio | The transaction rollback ratio is the ratio of transactions that have rolled back to the number of total transactions involving the EJB. This information is useful for several reasons. First, it may be useful for signaling a problem with an application. For example, an unexpectedly high rollback ratio may be caused by a problem with a resource used by the application. It may also be useful in gauging the efficiency of an application. A high transaction rollback ratio may mean that a lot of work is being done only to eventually be rolled back, which is inefficient. For information on what to tune in response to the transaction rollback ratio statistic, see Transaction Rollback Ratio in the WebLogic Server Performance and Tuning Guide.
Transaction Timeout Ratio | The transaction timeout ratio is the ratio of transactions that have timed out to the total number of transactions involving an EJB. Timeouts can be especially concerning because they are a signal of inefficiency. Every EJB request uses valuable server resources such as threads and bean instances. A timed out transaction means that server resources were tied up in vein. The transaction timeout ratio is a good indicator of a problem with an application. For information on what to tune in response to the transaction timeout ratio statistic, see Transaction Timeout Ratio in the WebLogic Server Performance and Tuning Guide.

Entity EJB Run-Time Statistics

## Raw Monitoring Data for Entity EJBs

This section defines the underlying run-time counts from which the statistics in Run-Time Statistics for Entity EJBs are calculated. To display the counts on the EJB --> Monitoring --> Entity EJBs tab page, select Customize this View and choose from the list of available data.

Table 91-2 Entity EJB Raw Monitoring Data

Run-Time Count | Description
--- | ---
Access Total Count | Displays the total number of times an attempt was made to get an instance from the free pool. This information is useful for giving context to the other free pool counts.
Activation Count | Displays the number of activated EJBs.
Beans In Use Current Count | Displays the number of bean instances currently in use from the free pool. This information is useful for tracking demand for your EJB. For example, this can be important when investigating an abnormal pool miss ratio.
Cache Access Count | Displays the total number of attempts to access a bean from the cache. This information is useful for giving context to other counts such as cache hits.
Cache Miss Count | Displays the total number of times an attempt to access a bean from the cache failed. This information is useful for determining the effectiveness of the EJB cache.
Cached Beans Current Count | Displays the total number of beans in cache.
Destroyed Total Count | Displays the total number of beans that have been destroyed.
EJB Name | Displays the name of the EJB.
Lock Mgr Access Count | Displays the total number of times an attempt was made to get a lock.
Lock Mgr Entries Current Count | Displays the current number of locks held.
Lock Mgr Timeout Total Count | Displays the total number of requests that timed out waiting for a lock.
Lock Mgr Waiter Total Count | Displays the total number of requests that have waited for a lock.
Miss Total Count | Displays the total number of times a failed attempt was made to get an instance from the free pool. An Attempt to get a bean from the pool will fail if there are no available instances in the pool. This information is useful for calculating the pool miss ratio.
Passivation Count | Displays the total number of EJBs that have been passivated.
Pool Timeout Total Count | Displays the total number of Threads that have timed out waiting for an available bean instance from the free pool. This information is useful for calculating the pool timeout ratio.
Pool Waiter Total Count | Displays the total number of requests that have waited for an instances from the pool.
Pooled Beans Current Count | Displays the current number of available bean instances in the free pool. This information is useful for tracking demand for your EJB. For example, this can be important when investigating an abnormal pool miss ratio.
Server | Displays the server instance upon which the EJB runs.
Transactions Committed Total Count | Displays the total number transactions that have been committed.
Transactions Rolled Back Total Count | Displays the total number transactions that have been rolled back.
Transactions Timed out Total Count | Displays the total number of transactions that have timed out.
Waiter Current Count | Displays the number of threads currently waiting for an available bean instance from the free pool. This information may be useful, for example, for investigating the cause of poor application performance at a particular time.

## Tasks

Monitoring EJBs

## Related Topics

Tuning WebLogic Server EJBs in WebLogic Server Performance and Tuning.