On Sun, Apr 29, 2012 at 6:20 PM, Hannu Krosing <ha...@2ndquadrant.com> wrote: > On Sun, 2012-04-29 at 12:03 +0100, Simon Riggs wrote: >> On Sat, Apr 28, 2012 at 8:40 PM, Hannu Krosing <ha...@krosing.net> wrote: >> >> > As to what LCRs should contain, it will probably be locical equivalents >> > of INSERT, UPDATE ... LIMIT 1, DELETE ... LIMIT 1, TRUNCATE and all DDL. >> >> Yeh >> >> > I would even go as far as propose a variant for DML-WITH-LIMIT-1 to be >> > added to postgresql's SQL syntax so that the LCRs could be converted to >> > SQL text for some tasks and thus should be easy to process using generic >> > text-based tools. >> > The DML-WITH-LIMIT-1 is required to do single logical updates on tables >> > with non-unique rows. >> > And as for any logical updates we will have huge performance problem >> > when doing UPDATE or DELETE on large table with no indexes, but >> > fortunately this problem is on slave, not master ;) >> >> While that is possible, I would favour the do-nothing approach. By >> making the default replication mode = none, we then require a PK to be >> assigned before allowing replication mode = on for a table. Trying to >> replicate tables without PKs is a problem that can wait basically. > > While this is a good approach in most cases, there is a large use case > for pk-less / indexless tables in large logfiles, where you may want to > do INSERT only replication, perhaps with some automatic partitioning on > logdate. Allowing this is probably something to look at in the first > release, even though I'm not sure wht would happen on violation of this > insert-only policy. > Should it > * refuse to continue and rollback the transaction (probably not) > * fail silently > * succeed but log the change locally > * succseed with some special flags so other side can treat it specially > without having to look up stuff in system catalog > * (if we mark the unique / pk fields in some special way anyway, then > the previous one is free :)
OK, I think an insert-only replication mode would allow that. -- Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
