When an Aggregator, Joiner, Lookup, or Rank transformation pages to the disk, the mapping log specifies the index and data cache sizes required to run the transformation in memory. For example, you run an Aggregator transformation called AGG_TRANS. The mapping log contains the following text:

The log shows that the index cache requires 286,720 bytes and the data cache requires 1,774,368 bytes to run the transformation in memory without paging to the disk.

When a Sorter transformation pages to the disk, the mapping log states that the Data Integration Service made multiple passes on the source data. The Data Integration Service makes multiple passes on the data when it has to page to the disk to complete the sort. The message specifies the number of bytes required for a single pass, which is when the Data Integration Service reads the data once and performs the sort in memory without paging to the disk.

For example, you run a Sorter transformation called SRT_TRANS. The mapping log contains the following text:

The log shows that the Sorter cache requires 14,128 MB so that the Data Integration Service makes one pass on the data.