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The caching module of XperienCentral stores a timestamp in the timestamp database for each cached web page. This timestamp is needed in order to determine whether the web page needs to be regenerated or whether it can be retrieved from the cache. For high volume websites, the number of web page requests per second can be so high that even the relatively simple task of performing one SQL query to retrieve this timestamp from the database can cause a bottleneck. If this exceeds 500 milliseconds, it may indicate a performance issue.
To prevent timestamp retrieval from becoming a bottleneck, timestamps can be cached in memory for <n> milliseconds. Note that this also causes a delay of <n> milliseconds; during the <n> milliseconds, modified web pages will not be regenerated. It is recommended that you set timestamp caching to at least 5000 milliseconds (5 seconds). If you set timestamp caching to fewer than 5000 milliseconds, this can cause database bottlenecks especially for websites that experience a large number of page requests.
Timestamp caching is configured in the XperienCentral Setup Tool. Navigate to the "Frontend System Settings" section of the [General configuration] tab:
Lowering Page Response Times
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