Described systems and techniques enable the intake of large numbers of files having widely varying structures and formats, as well as generation of dynamic slot indexes that enable fast and reliable searching of the files. Unique data patterns within the files are used to generate unique pattern models, which enable model-specific mappings of file fields to slots of a dynamic slot index. Accordingly, the dynamic slot indexes may reuse a single slot for multiple fields. Complex queries may then be processed in a time-efficient and resource-efficient manner, even when rapidly ingesting huge numbers of files having indeterminate data patterns from many different sources.