In general, a cursor closes when a COMMIT is performed. There are two exceptions to this behavior:
The close_on_endtrans database option is set to Off.
A cursor is opened WITH HOLD, which is the default with Open Client and JDBC.
If either of these two cases is true, the cursor remains open on a COMMIT.
If a transaction rolls back, then cursors close except for those cursors opened WITH HOLD. However, don't rely on the contents of any cursor after a rollback.
The draft ISO SQL3 standard states that on a rollback, all cursors (even those cursors opened WITH HOLD) should close. You can obtain this behavior by setting the ansi_close_cursors_on_rollback option to On.
If a transaction rolls back to a savepoint, and if the ansi_close_cursors_on_rollback option is On, then all cursors (even those cursors opened WITH HOLD) opened after the SAVEPOINT close.
You can change the isolation level of a connection during a transaction using the SET OPTION statement to alter the isolation_level option. However, this change does not affect open cursors.
A snapshot of all rows committed at the snapshot start time is visible when the WITH HOLD clause is used with the snapshot, statement-snapshot, and readonly-statement-snapshot isolation levels. Also visible are all modifications completed by the current connection since the start of the transaction within which the cursor was open. For more details about supported isolation levels, see Isolation levels and consistency and isolation_level option [database] [compatibility].
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