The Genero programming language supports scrollable
cursors.
Netezza® does support
native scrollable cursors.
Solution
The Netezza database driver emulates scrollable
cursors by fetching rows in a temporary file. On UNIX™, the temp files are created in
the directory defined by the DBTEMP, TMPDIR, TEMP or TMP environment
variables (the default is /tmp). On Windows™,
the temp files are created with the _tempnam() MSVCRT API call.
Note:
- Native scrollable cursors are normally handled by the database
server (only pieces of the result-set are sent to the
client application). With emulated scrollable cursors,
when scrolling to the last row, all rows will be fetched into the
temporary file. This can generate a lot of network traffic
and can produce a large temporary file if the result-set
contains a lot of rows. Additionally, programs are dependent on the
file system resource allocated to the OS user (ulimit).
- In the case of a runtime system crash, the temporary files created
for scrollable cursors are not removed automatically.
Therefore, is it possible that you will find some unexpected
files in the temp directory. Before removing such files, you must
make sure that these files are no longer used by running
processes. Recent operating systems take care of that,
by removing unused temp files periodically.