Обсуждение: Synchronous replication
Is it possible to set up synchronous replication to more that one node in a cluster? Or, am I limited to one synchronous node and one asynchronous node?
Assuming my replicated databases are on nodes: testqa1, testqa2. What would my synchronous_standby_names entry in my postgresql.conf on my master database?
Regards
John Wiencek
On 01/13/2016 12:28 PM, jwiencek3@comcast.net wrote: > Is it possible to set up synchronous replication to more that one node > in a cluster? Or, am I limited to one synchronous node and one > asynchronous node? Yes you can have N number of synchronous slaves. However, be careful. It can be a huge performance hit. > > Assuming my replicated databases are on nodes: testqa1, testqa2. What > would my synchronous_standby_names entry in my postgresql.conf on my > master database? The IP address that each is binding to. JD -- Command Prompt, Inc. http://the.postgres.company/ +1-503-667-4564 PostgreSQL Centered full stack support, consulting and development.
On Thu, Jan 14, 2016 at 9:34 AM, Joshua D. Drake <jd@commandprompt.com> wrote: > On 01/13/2016 12:28 PM, jwiencek3@comcast.net wrote: >> >> Is it possible to set up synchronous replication to more that one node >> in a cluster? Or, am I limited to one synchronous node and one >> asynchronous node? > > > Yes you can have N number of synchronous slaves. However, be careful. It can > be a huge performance hit. Note that only one of the listed standbys is a synchronous standby at any given time though. That is, when you commit, the primary server will wait just for that one server to report that it has fsync'ed the WAL. (There is a patch being developed to change that so that you might be able to wait for more than one in a future release). -- Thomas Munro http://www.enterprisedb.com
Thank you all for the quick replies. John Wiencek On 1/13/16, 2:43 PM, "Thomas Munro" <thomas.munro@enterprisedb.com> wrote: >On Thu, Jan 14, 2016 at 9:34 AM, Joshua D. Drake <jd@commandprompt.com> >wrote: >> On 01/13/2016 12:28 PM, jwiencek3@comcast.net wrote: >>> >>> Is it possible to set up synchronous replication to more that one node >>> in a cluster? Or, am I limited to one synchronous node and one >>> asynchronous node? >> >> >> Yes you can have N number of synchronous slaves. However, be careful. >>It can >> be a huge performance hit. > >Note that only one of the listed standbys is a synchronous standby at >any given time though. That is, when you commit, the primary server >will wait just for that one server to report that it has fsync'ed the >WAL. (There is a patch being developed to change that so that you >might be able to wait for more than one in a future release). > >-- >Thomas Munro >http://www.enterprisedb.com