Attached is a working updateable cursors patch. The core functionality has
been implemented and the patch also contains the regression tests and
documentation.
However there are still a couple of TODOs that needs to be done. The planner
has to be taught to treat a DELETE/UPDATE WHERE CURRENT OF as a TidScan.
Currently it follows the sequential scan route and extracts the current tuple
based on the cursor position from the portal. Also, an issue that needs to
be looked at is how to treat joins with an updateable cursor. Currently it is
allowed and when it comes to delete or update, an error message is thrown
from the executor.
Rgds,
Arul Shaji
