This section explains aspects of the process that the cache warming service uses to reload cached data. An overview of the cache warming process is provided below.
You initiate deployment from your application’s publishing server.
The deployment agent component of your application’s production server prepares for deployment by generating a list of cached repository item identifiers.
The deployment agent component of the production server continues the deployment by switching data sources and invalidating cached repository items.
When the data source switch is complete, the deployment agent component invokes the cache warming service component to begin cache warming.
The cache warming service examines the list of repository items that were stored earlier in the process. It reloads each item into the cache.
If the cache warming service component completes the cache warming operation, it waits for the next deployment. If another deployment occurs before cache warming is complete, the cache warming service merges the new list of cached repository items with the one it was already working on and continues to reload all the repository items.
The cache warming service reloads cached data that was invalidated by selective cache and full cache invalidation in the same way. The manner in which cached data was invalidated does not affect the way you use or configure cache warming.
Repository Items Selection
The cache warming service affects all cached repository items in switched data sources after a deployment. If you have configured caching for a repository item descriptor and configured a switching data source for the repository that contains it, the cache warming service will attempt to reload the cached data. The cache warming service begins reloading cached data after the data sources have been switched during a publishing deployment. See information about configuring repository item descriptors for caching in the Repository Guide. See information about configuring switching data sources in the Platform Installation and Configuration Guide.
You can configure the cache warming service to omit specific repositories from cache warming. To omit specific repositories from cache warming:
Configure the
excludeRepositoryListproperty of the/atg/epub/cachewarming/CacheWarmingServiceConfigurationcomponent of your production server. The configuration file for this component is:<ATG11dir>/home/servers/production_server_name/localconfig/atg/epub/
cachewarming/CacheWarmingServiceConfiguration.propertiesInclude the component path of each repository in the value for
excludeRepositoryList:excludeRepositoryList=/atg/userprofiling/PersonalizationRepository,\
/atg/multisite/SiteRepositoryRestart your application servers.
By default, the cache warming service will only load repository item properties from primary tables. If you want to load repository item properties from auxiliary or multi-type tables include those properties in the extraProperties configuration property. See information about SQL repository types in the Repository Guide.
To include repository item properties from auxiliary or multi-type tables when using cache warming:
Configure the
extraPropertiesproperty of the/atg/epub/cachewarming/CacheWarmingServiceConfigurationcomponent of your production server. The configuration file for this component is:<ATG11dir>/home/servers/production_server_name/localconfig/atg/epub/
cachewarming/CacheWarmingServiceConfiguration.propertiesInclude the component path of the repository, a colon character, the item descriptor name, the equals character, and the property name in the value for
extraProperties. Separate multiple repository paths with commas. Separate multiple property names with semicolons. See the following example:extraProperties=/atg/commerce/catalog/ProductCatalog:\
catalog=rootCategories;rootCategoryIds, \
/atg/commerce/pricing/priceLists/PriceLists:complexPrice=price;levelsRestart your application servers.
Background Cache Warming
By default, the cache warming service launches cache warming in one or more separate Java threads. This allows cache warming to proceed at the same time that a production server is finishing deployment.
To configure the number of separate threads used for cache warming:
Configure the
maxCacheWarmingThreadCountproperty of the/atg/epub/cachewarming/CacheWarmingServiceConfigurationcomponent of your production server. The configuration file for this component is:<ATG11dir>/home/servers/production_server_name/localconfig/atg/epub/
cachewarming/CacheWarmingServiceConfiguration.propertiesInclude the number of threads in the value for
maxCacheWarmingThreadCount.maxCacheWarmingThreadCount=3Restart your application servers.
You can configure the cache warming service to run in the same thread used by the publishing deployment. If you do this, the deployment will be blocked until cache warming is complete. To configure the cache warming service to run in the same thread used by the publishing deployment:
Configure the
backGroundWarmingproperty of the/atg/epub/cachewarming/CacheWarmingServiceConfigurationcomponent of your production server. The configuration file for this component is:<ATG11dir>/home/servers/production_server_name/localconfig/atg/epub/
cachewarming/CacheWarmingServiceConfiguration.propertiesSet the value of
backGroundWarmingtofalse.backGroundWarming=falseRestart your application servers.
Cache Warming Priority
You can configure the cache warming service to reload specific repositories and repository item descriptors first. After the cache warming service has loaded items from the repositories you choose, it loads items from the remaining repositories in random order. You can also configure the cache warming priority of specific repository item descriptors within the repositories that you choose to warm first.
To configure the cache warming service to warm specific repositories and repository item descriptors first:
Configure the
repositoryPriorityListproperty of the/atg/epub/cachewarming/CacheWarmingServiceConfigurationcomponent of your production server. The configuration file for this component is:<ATG11dir>/home/servers/production_server_name/localconfig/atg/epub/
cachewarming/CacheWarmingServiceConfiguration.propertiesInclude a comma-separated list of the component paths of the repositories that you want to warm first in the value for
repositoryPriorityList. If you want specific repository item descriptors within those repositories to be warmed first, include the equals sign and then a semicolon-separated list of the repository item descriptor names.repositoryPriorityList=\
/atg/commerce/catalog/ProductCatalog=catalog;category,\
/atg/commerce/pricing/priceLists/PriceListsRestart your application servers.
Staggering Data Source Switching
You can configure your publishing server to wait a period of time between switching the data source for each production server in a cluster. This reduces the number of production servers that will begin cache warming at the same time. If you have a large number of production servers you may need to restrict the number that are loading data from the database into the cache at the same time.
Note: Staggering the data source switching in your production server cluster may cause data inconsistency. Simultaneous user sessions on different production servers may have inconsistent experiences.
To set the delay period between the data source switches for a publishing deployment:
Configure the
dataSourceSwitchingSleepTimeMilliSecondsproperty of the/atg/epub/DeploymentServercomponent of your publishing server. The configuration file for this component is:<ATG11dir>/home/servers/publishing_server_name/localconfig/atg/epub/
DeploymentServer.propertiesInclude the delay period in milliseconds in the value for
dataSourceSwitchingSleepTimeMilliSeconds.dataSourceSwitchingSleepTimeMilliSeconds=60000Restart your application servers.
Batching Cache Warming Transactions
You can control the number of repository items that the cache warming service will reload in each database transaction. Adjust the number of items in each transaction to suit the nature and size of the data stored in each item.
To configure the number of repository items loaded in each transaction:
Configure the
maxBatchLoadingSizeproperty of the/atg/epub/cachewarming/CacheWarmingServiceConfigurationcomponent of your production server. The configuration file for this component is:<ATG11dir>/home/servers/production_server_name/localconfig/atg/epub/
cachewarming/CacheWarmingServiceConfiguration.propertiesInclude the maximum number of repository items in the value for
maxBatchLoadingSize.maxBatchLoadingSize=200Restart your application servers.
Note: Typical settings for the maxBatchLoadingSize property are less than 200.
User Session Threshold
You can configure the cache warming service to stop reloading cached data if the number of active user sessions exceeds a specific level. Use this configuration to make sure that the cache warming service does not reduce application performance during peak periods of user activity. The user session threshold is the maximum number of user sessions allowed before the cache warming service will stop reloading cached data.
If the cache warming service stops because the user session threshold has been reached, it will not resume loading the cache. The cache warming service will attempt to reload the cache again during the next deployment. When the next deployment occurs, the production server deployment agent component will compile a new list of cached repository items and the cache warming service will reload only those items.
The user session threshold is not configured by default. Until you configure a user session threshold the cache warming service will not consider how many user sessions are active.
To configure the user session threshold:
Set the
cacheWarmingThresholdControllerproperty of the/atg/epub/cachewarming/CacheWarmingServiceConfigurationcomponent of your production server. The configuration file for this component is:<ATG11dir>/home/servers/production_server_name/localconfig/atg/epub/
cachewarming/CacheWarmingServiceConfiguration.propertiesSet the following value for
cacheWarmingThresholdController:cacheWarmingThresholdController=/atg/epub/cachewarming/
SessionCountControllerSet the
sessionCountThresholdproperty of the/atg/epub/cachewarming/SessionCountControllercomponent of your production server to the maximum number of user sessions allowed before cache warming will stop. For example, if you set the threshold to 99, cache warming will stop when there are 100 active user sessions.The configuration file for this component is:
<ATG11dir>/home/servers/production_server_name/localconfig/atg/epub/
cachewarming/SessionCountController.propertiesRestart your application servers.
Note: Setting this property to a negative number causes the cache warming service to reload repository items without considering how many user sessions are active.
Maximum Number of Repository Items Warmed
You can configure the cache warming service to stop reloading cached data when it reaches a maximum number of repository items. By default the cache warming service will reload an unlimited number of repository items.
To configure the maximum number of repository items that the cache warming service will reload for each deployment:
Configure the
maxCacheWarmingItemCountproperty of the/atg/epub/cachewarming/CacheWarmingServiceConfigurationcomponent of your production server. The configuration file for this component is:<ATG11dir>/home/servers/production_server_name/localconfig/atg/epub/
cachewarming/CacheWarmingServiceConfiguration.propertiesInclude the maximum number of repository items in the value for
maxCacheWarmingItemCount.maxCacheWarmingItemCount=10000Restart your application servers.
Note: Setting this property to a negative number causes the cache warming service to reload an unlimited number of repository items.
