Abstract: Data to be stored in a data block for a columnar database table may be compressed according to a multi-level compression scheme. Data to be stored in the data block may be received. The data may be compressed according a column-specific compression technique to produce compressed data. The compressed data may then be compressed according to a second compression technique different than the column-specific compression technique to produce multi-level compressed data. The multi-level compressed data may be stored in the data block. When reading from the data block, multi-level compressed data may be decompressed according to the column-specific compression technique and the default compression technique applied to the data.

Abstract: A virtual sandbox environment enables a publisher to enforce rules for supplemental content, such as third party advertising, displayed on a page or other grouping of content from the publisher. One or more rule sets can be applied or enforced in a number of ways, such as through active script on a page, as part of a browser or other such application or interface, or via a third party such as an anti-virus application or service. A rule set can specify behavior that is allowed or prohibited, in various circumstances, as well as actions to be taken in response to any unapproved or prohibited behavior. Rule sets can be cached by a client device such that any number of pages or other groupings of content can utilize the same rule set without reloading the set.