sa_snapshots system procedure

Returns a list of snapshots that are currently active.

Syntax

sa_snapshots( )

Result set

Column name	Data type	Description
connection_num	INT	The connection ID for the connection on which the snapshot is running.
start_sequence_num	UNSIGNED BIGINT	A unique number that identifies the snapshot.
statement_level	BIT	True if the snapshot was created with statement-snapshot or readonly-statement-snapshot. Otherwise, false.

Several statement snapshots can exist on one connection. For nested or interleaved statements running under statement snapshot isolation levels, each one begins a different statement snapshot with its first read or update.

Usually there is only one transaction snapshot per connection (one entry per connection in sa_snapshots with statement_level=0). However, a snapshot associated with a cursor never changes after the cursor's first fetch and a cursor opened WITH HOLD stays open through a commit or rollback. If the cursor has an associated snapshot, then the snapshot also persists. Therefore, it is possible for multiple transaction snapshots to exist for the same connection_num: one for the current transaction snapshot and one or more for old transaction snapshots that persist because of WITH HOLD cursors.