IBM 6.1.X manual BS P HE R E P O R T AL V 6 T U N I N G G U I D E

Supported values are true and false. The default values shipped in WebSphere Portal V6.1 should apply to most configurations. If you do not have a cluster there may be a small performance benefit to setting this property to false since a different cache implementation is used. We did not modify the defaults in our single node measurement environments.

If this parameter is false in a cluster, it can ultimately lead to data inconsistencies between the cluster members.

replacement: The cache replacement algorithm used by these caches works on the frequency of recent access to cache entries; entries that have been used frequently are less likely to be discarded than entries that have not been used frequently. This parameter controls how long the access history will be kept. A setting of aggressive means those only recently accessed entries will be considered, which causes stale entries to be discarded more quickly. The opposite setting, conservative, will consider a longer access history. The intermediate setting of moderate is appropriate for most caches.

admit-threshold:Caches that have a very high insert rate may cause useful entries to be discarded prematurely. An admittance threshold restricts the rate at which entries are allowed into the cache by only allowing them to enter after an attempt has been made to insert the same entry into the cache multiple times. The default value of 0 means “no admittance threshold”, which will allow entries into the cache on the first insert attempt. This is appropriate for most caches. A higher value indicates that a cache entry will not be allowed into the cache until that many attempts have been made to insert the same key. For example, a value of 2 means that the first two attempts to insert a cache entry will be ignored, and the third attempt will insert the value into the cache. We did not modify the admit-thresholdfor any cache in our measurement environments.

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W E BS P HE R E P O R T AL V 6 . 1 T U N I N G G U I D E