On Tue, Apr 7, 2015 at 6:11 PM, Peter Geoghegan <p...@heroku.com> wrote: > No. For one thing, unique index enforcement still requires the tuples > to be treated as a conflict while the other transaction is running > IMV. >
Not sure if I understand correctly: in uniqueness check, we see all possible tuples with a dirty snapshot. For a tuple version inserted and updated by myself, it is surely dead no matter how the transaction ends. So I interpret that we can safely pruning the version. Early pruning may cause some behavior change though. For example, here is a T1: begin; -- loop the following statements many times insert into pk values (1); -- uniqueness defined delete from pk; abort; If another transaction T2 coming later than T1, and if we prune early, then T1 can suddenly hang on insertion waiting for T2 to complete. But does this violate any isolation rule? Thanks, Qingqing -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
