Supporting Cursor Snapshot Semantics

摘要

A database upon opening each of at least one cursor for a transaction, assigns each statement forming part of a transaction a statement sequence number (SSN) involving at least one row of the database. Thereafter, temporary timestamps are assigned to the at least one row using a transaction identifier and the corresponding SSN. Further, active cursors are monitored such that a final timestamp is prevented from being associated with each row until it has no remaining cursors. Related apparatus, systems, techniques and articles are also described.

主权项

1. A method for implementation by one or more hardware data processors forming part of at least one computing device, the method comprising:
assigning, by a database upon opening each of at least one cursor for a transaction, each statement forming part of the transaction a statement sequence number (SSN) involving at least one row of the database; assigning temporary timestamps to the at least one row using a transaction identifier and the corresponding SSN; monitoring active cursors; and preventing a final timestamp to be associated with each row until there are no remaining active cursors for such row.