1. A system, comprising: a plurality of storage nodes, each of which comprises at least one processor and a memory, wherein the plurality of storage nodes is configured to collectively implement a distributed log-structured storage system of a database service configured to: receive a plurality of log records, from one or more database engine head nodes of the database service, wherein each of the plurality of log records describes a respective change to data stored by the database service as part of a log and is further associated with a respective log sequence identifier; store the plurality of log records among the plurality of storage nodes; and perform an operation upon two or more log sections of the log included in the plurality of log records to generate at least one new log section, wherein the two or more log sections describe one or more respective versions of the data maintained by the plurality of log records, wherein the operation transforms the plurality of log records stored among the plurality of storage nodes such that the at least one new log section describes a version of the data maintained as a result of the transformation of the plurality of log records, wherein the two or more log sections are operands for the operation.