>> Hello hackers. >> >> I am struggling to understand why standby.max_connections must be higher >> than >> primary.max_connections.Do someone know the reason why? > > Because the KnownAssignedXIDs and lock tables on the standby need to > be large enough to contain the largest snapshot and greatest number of > AccessExclusiveLocks that could exist on the master at any given time. > >> I think this restriction obstructs making a flexible load balancing. >> I'd like to make standby database to use load balancing.Of course >> a role of a standby server is different from one of a master server. >> So I think it it natural that I want to set standby.max_connections less >> than >> primary.max_connections. > > Your load balancer should probably have a configuration setting that > controls how many connections it will try to make to the database, and > you can set that to a lower value than max_connections. > Hi Robert.
I understand the reason Why standby.max_connections must be higher than primary.max_connections. I'll try to restrict sessions by load balancer. Thanks. 2013/12/11 Robert Haas <robertmh...@gmail.com> > On Tue, Dec 10, 2013 at 3:34 AM, 山田聡 <satoshi.yamada...@gmail.com> wrote: > > Hello hackers. > > > > I am struggling to understand why standby.max_connections must be higher > > than > > primary.max_connections.Do someone know the reason why? > > Because the KnownAssignedXIDs and lock tables on the standby need to > be large enough to contain the largest snapshot and greatest number of > AccessExclusiveLocks that could exist on the master at any given time. > > > I think this restriction obstructs making a flexible load balancing. > > I'd like to make standby database to use load balancing.Of course > > a role of a standby server is different from one of a master server. > > So I think it it natural that I want to set standby.max_connections less > > than > > primary.max_connections. > > Your load balancer should probably have a configuration setting that > controls how many connections it will try to make to the database, and > you can set that to a lower value than max_connections. > > -- > Robert Haas > EnterpriseDB: http://www.enterprisedb.com > The Enterprise PostgreSQL Company >
