I have some questions on PostgreSQL cursors (not PL/pgSQL but the libpq implementation):
What happens when my cursor hit the end of the table? Does it close automatically? I suppose if I declare it as a SCROLLABLE cursor, it should not close at all.
The lifetime of cursors created by the DECLARE ... SQL command longs until the end of the session, or until it explicitly closed by either CLOSE ... or DISCARD SQL commands.
If I have declared a cursor and the session got disconnected, can I reattach back to the cursor if I know the cursor name? I believe this is not possible but I'm not very sure.
When session ends all cursors are deallocated automatically. You should open the new cursor on reconnect.