Re: Some questions about mammoth replication
От | Joshua D. Drake |
---|---|
Тема | Re: Some questions about mammoth replication |
Дата | |
Msg-id | 20071011095621.7b51feb0@scratch обсуждение исходный текст |
Ответ на | Re: Some questions about mammoth replication (Alexey Klyukin <alexk@commandprompt.com>) |
Список | pgsql-hackers |
On Thu, 11 Oct 2007 19:10:18 +0300 Alexey Klyukin <alexk@commandprompt.com> wrote: > Marko Kreen wrote: > > On 10/11/07, Alexey Klyukin <alexk@commandprompt.com> wrote: > > > Hannu Krosing wrote: > > > > For what use cases do you think your WAL-based approach is > > > > better than Slony/Skytools trigger-based one ? > > > > > > A pure trigger based approach can only replicate data for the > > > commands which fire triggers. AFAIK Slony is unable to replicate > > > TRUNCATE command (I don't know if Skytools can). Replicator > > > doesn't have this limitation. > > > > No, Skytools is same as Slony. > > > > Can you also replicate changes to system tables? > > No, we need a table to have primary key to be able to replicate it. > From the other hand replicating a system relation can be dangerous, > i.e. what if you replicate the contents of pg_class without > corresponing relations on the slave, that's why explicitly forbid > enabling replication for relations from pg_catalog namespace. We can however replicate large objects and specific system commands like GRANT/REVOKE and CREATE/DROP user. The latter being done via triggers. Joshua D. Drake > > Regards, -- === The PostgreSQL Company: Command Prompt, Inc. === Sales/Support: +1.503.667.4564 24x7/Emergency: +1.800.492.2240 PostgreSQL solutions since 1997 http://www.commandprompt.com/ UNIQUE NOT NULL Donate to the PostgreSQL Project: http://www.postgresql.org/about/donate PostgreSQL Replication: http://www.commandprompt.com/products/
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