A reader with Cursor Stability isolation acquires a shared
lock on the row that is currently fetched. This action assures that
no other user can update the row until the user fetches a new row.
In the example for a cursor in Locks placed
for cursor stability,
at fetch a row the database server releases the lock on the
previous row and places a lock on the row being fetched. At close
the cursor, the server releases the lock on the last row. Figure 1. Locks placed
for cursor stability
set isolation to cursor stability
declare cursor for SELECT * FROM customer
open the cursor
while there are more rows
fetch a row
do work
end while
close the cursor
If you do not use a cursor to fetch data, Cursor Stability isolation
behaves in the same way as Committed Read. No locks are actually placed.
