Gbase 8C transaction ID and snapshot (I)

Internal affairs ID type （xid） yes 64 position . The data types used by these functions txid_snapshot, Store transactions at a specific time ID Visibility information . Its components are described in table 1.

surface 1  Snapshot component

name	describe
xmin	Earliest transaction ID（txid） Still active . All earlier transactions will have been committed visible , Or roll back directly .
xmax	As an unallocated txid. All greater than or equal to this txids All are snapshot times that haven't started yet , So it's not visible .
xip_list	Active in the current snapshot txids. This list is only included in xmin and xmax Activities between txids; Possibly active txids higher than xmax. Between and equal to xmin、 Less than xmax, And not on this list txid, At this time, the snapshot has been completed , Therefore, check whether it is visible or rolled back according to the submission status . This list does not contain the... Of sub transactions txids.

txid_snapshot The text of is expressed as ：xmin:xmax:xip_list.

Example ：10:20:10,14,15 You mean for ：xmin=10, xmax=20, xip_list=10, 14, 15.