On Mon, Mar 12, 2012 at 9:24 PM, Noah Misch <n...@leadboat.com> wrote: > When we lock an update-in-progress row, we walk the t_ctid chain and lock all > descendant tuples. They may all have uncommitted xmins. This is essential to > ensure that the final outcome of the updating transaction does not affect > whether the locking transaction has its KEY SHARE lock. Similarly, when we > update a previously-locked tuple, we copy any locks (always KEY SHARE locks) > to the new version. That new tuple is both uncommitted and has locks, and we > cannot easily sacrifice either property. Do you see a way to extend your > scheme to cover these needs?
No, I think that sinks it. Good analysis. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
