1. A computer program product, embodied in a non-transitory computer-readable storage medium, the computer program product being operable to cause at least one data processing apparatus to perform operations comprising: performing, in parallel, block compression for each of a plurality of columns of data; storing, for each column of data, changes to the column of data after the block compression is performed in a different one of a plurality of delta buffers, wherein the delta buffers are separate from the corresponding columns of data; and asynchronously integrating, for each column of data, changes stored in the corresponding delta buffer into the corresponding column of data, wherein the columns of data and the delta buffers are searchable prior to the integration, and wherein search results from the columns of data and the delta buffers are merged to form a composite result.