The nzDbosSpill file
The host data handling software in DbosEvent has a disk work area that the system uses for large sorts on the host.
The IBM Netezza Appliance and
IBM Netezza Appliance system has two
sorting mechanisms:
- The Host Merge that takes sorted SPU return sets and produces a single-sorted set. It uses temporary disk space to handle SPU double-duty situations.
- A traditional sorter that begins with a random table on the host and sorts it into the order that you want. It can use a simple external sort method to handle large data sets.
The file on the Linux® host for this disk work area is $NZ_TMP_DIR/nzDbosSpill. Within DBOS, there is a database that tracks segments of the file presently in use.
To avoid having a runaway query use up all the host computer disk
space, there is a limit on the DbosEvent database, and hence the size
of the Linux file. This limit
is in the Netezza Performance Server Registry file. The tag for the value is startup.hostSwapSpaceLimit.