2011/1/21 Anssi Kääriäinen <anssi.kaariai...@thl.fi>: > Sorry for bothering all of you, but I just don't get this. What if T2 rolls > back instead of committing? Then the snapshot of T3 would have been valid, > right? Now, for the snapshot of T3 it doesn't matter if T2 commits or if it > doesn't, because it can't see the changes of T2 in any case. Thus, it would > seem that the snapshot is valid. On the other hand I can't see anything > wrong in the logic in your post. What am I missing? I am feeling stupid... > > At least for dumps I don't see how T2 can matter (assuming T3 is the > pg_dump's snapshot). Because if you reload from the dump, T2 never happened > in that dump. In the reloaded database it just did not exist at all.
This has been discussed before; in [1] I summarized: "IOW, one could say that the backup is consistent only if it were never compared against the system as it continued running after the dump took place." Nicolas [1] <URL:http://archives.postgresql.org/pgsql-hackers/2010-09/msg01763.php> -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
