Hybris Entity Region Cache Test

The SAP Hybris comes with cache feature which intercepts calls whenever API is accessed and caches the results. If data is queried again it is either returned from returned from cache or retrieved from database and written to cache.

SAP Hybris cache can be split into multiple partitions called regions. Each region cache can be configured separately and can hold its own set of handled types. Entity Region Cache is used for storing entities of all types expect type system ones.

This test monitors Entity Region Cache for performance and ensure that majority of query response are returned from cache which will result in optimal overall system performance.

Target of the test : A SAP Hybris system

Agent deploying the test : An internal/remote agent

Outputs of the test : One set of results for entity region cache belonging to each tenant

Configurable parameters for the test
Parameter Description

Test Period

How often should the test be executed

Host

The host for which the test is to be configured.

Port

Specify the port at which the specified host listens. By default, this is 9002.

JMX Remote Port

Specify the port at which the JMX listens for requests from remote hosts. Ensure that you specify the JMX remote port number of the SAP Hybris monitoring application. The default is 12002.

JNDI Name

The JNDIname is a lookup name for connecting to the JMX connector. By default, this is jmxrmi. If you have registered the JMX connector in the RMI registry using a different lookup name, then you can change this default value to reflect the same.

JMX User and JMX Password

If JMX requires authentication only (but no security), then ensure that the user and password parameters are configured with the credentials of a user with read-write access to JMX.

Confirm Password

Confirm the password by retyping it here.

Provider

This test uses a JMX Provider to access the MBean attributes of the target Java application and collect metrics. Specify the Provider as value “default”.

Timeout

Specify the duration (in seconds) for which this test should wait for a response from the target Java application. If there is no response from the target beyond the configured duration, the test will timeout. By default, this is set to 1000 seconds if the Mode is JMX

Detailed Diagnosis

To make diagnosis more efficient and accurate, the eG Enterprise embeds an optional detailed diagnostic capability. With this capability, the eG agents can be configured to run detailed, more elaborate tests as and when specific problems are detected. To enable the detailed diagnosis capability of this test for a particular server, choose the On option. To disable the capability, click on the Off option.

The option to selectively enable/disable the detailed diagnosis capability will be available only if the following conditions are fulfilled:

  • The eG manager license should allow the detailed diagnosis capability
  • Both the normal and abnormal frequencies configured for the detailed diagnosis measures should not be 0.

Measures made by the test
Measurement Description Measurement Unit Interpretation

Cache entries

Indicates the total number of entries in cache during the last measurement period.

Number

If the cache fill ratio is towards 100%, it may be a sign that either the cache size is too small for the transactions it is supporting or there is some issue with cache invalidation and eviction algorithm.

 

Cache fill ratio

Indicates the numbed of entries in the last measurement period against maximum entries in the cache.

Percentage

Maximum Entries

Indicates the maximum number of entries allowed in the entity region cache.

Number

Invalidation rate

Indicates the number of items invalidated in the cache in a min during last measurement period.

Number/Min

In systems with high number of write transactions, the invalidation rate should be high, if that is not the case, it needs to be investigated.

Eviction rate

Indicates the number of items evicted from the cache in a min during last measurement period.

Number/Min

Old items which are not used for long need to be continuously evicted from cache to make place for new entries. If the eviction rate is low, it could lead to filling of cache quickly.

Fetch rate

Indicates the number of items fetched per min during the last measurement period.

Number/Min

 

Hit rate

Indicates the number of times where the item was found in a min during the last measurement period.

Number/min

Some key indicators of degradation in performance can be -

  • Downward trend of Hit rate measured over multiple consecutive measurement periods.

  • Upward trend of Miss rate measured over multiple consecutive measurement periods.

  • Comparatively low value of Hit ratio.

Miss rate

Indicates the number of times where the item was not found in a min during the last measurement period.

Number/min

Hit Ratio

Indicate the percent of items requested, which were in the cache during the last measurement period.

Percentage