SYSTEM FOR DATA STRUCTURE LOADING WITH CONCURRENT IMAGE COPY

Data is loaded to a data structure while an image copy of the data structure is concurrently formed. After data records are obtained from one or more data sources, each of the data records is associated with one of multiple pages. As each page is completed, it is written to a primary data structure. Also upon completion of each page in the primary data structure, concurrently with storage of the page in the primary data structure, an image copy of the page is made in an image copy data set. Partially or completely failed primary data structures may also be restored using image copies made according to the invention. Timestamps mark the time at which each page are made; image copy pages include the same timestamp as their respective primary pages. Upon detecting a data structure failure, each page of the image copy is sequentially reviewed. For each image page being reviewed, the page's timestamp is compared with the timestamp of the corresponding page from the primary data structure. The page is copied from the image copy to the primary data structure only if the timestamp comparison indicates that the image page is more recent than the page from the primary data structure.