Resource pre-fetch using age threshold

A system, comprising:

• one or more processing devices;
• and
• one or more non-transitory machine-readable storage devices storing instructions that are executable by the one or more processing devices to cause performance of operations comprising:
• identifying a set of resources in response to crawling a plurality of webpages, each resource in the set of resources being a component of a webpage in the plurality of webpages, and wherein each of the webpages uses at least one of the resources in the set of resources to present content;
• for each resource in the set of resources:
• determining an age of the resource using a timestamp for the resource that indicates a time that the webpage was previously crawled to identify the resource as a component of the webpage;
• and
• determining a pre-fetch measure of the resource based on the age of the resource and usage information that describes use of the resource by one or more webpages;
• for each respective resource that is determined to have a pre-fetch measure that exceeds a threshold measure, determining whether an age of the respective resource exceeds a threshold age;
• and
• for each respective resource that is determined to have an age that exceeds the threshold age, generating an index entry at a pre-fetch index, the index entry including a command to pre-fetch the respective resource based on the determination that the age of the respective resource exceeds the threshold age,
• wherein at least one index entry is generated at the pre-fetch index.

One or more non-transitory machine-readable storage devices storing instructions that are executable by one or more processing devices to cause performance of operations comprising:

• identifying a set of resources in response to crawling a plurality of webpages, each resource in the set of resources being a component of a webpage in the plurality of webpages, and wherein each of the webpages uses at least one of the resources in the set of resources to present content;
• for each resource in the set of resources:
• determining an age of the resource using a timestamp for the resource that indicates a time that the webpage was previously crawled to identify the resource as a component of the webpage;
• and
• determining a pre-fetch measure of the resource based on the age of the resource and usage information that describes use of the resource by one or more webpages;
• for each respective resource that is determined to have a pre-fetch measure that exceeds a threshold measure, determining whether an age of the respective resource exceeds a threshold age;
• and
• for each respective resource that is determined to have an age that exceeds the threshold age, generating an index entry at a pre-fetch index, the index entry including a command to pre-fetch the respective resource based on the determination that the age of the respective resource exceeds the threshold age,
• wherein at least one index entry is generated at the pre-fetch index.