For block storage databases, Essbase Server allocates the data cache memory area to hold uncompressed data blocks. If you are using the DLTHREADSWRITE configuration setting, each thread specified by that setting uses an area in the data cache equal to the size of an expanded block.
Depending on the size of the block, the number of threads, and how much data cache is used by other concurrent operations during a data load, it may be possible to need more data cache than is available. In such circumstances, decrease the number of threads or increase the size of the data cache.