Re: Why standby.max_connections must be higher than primary.max_connections?

<div dir="ltr">>> Hello hackers.<br />>><br />>> I am struggling to understand why
standby.max_connectionsmust be higher<br />>> than<br />>> <a
href="http://primary.max_connections.Do">primary.max_connections.Do</a>someone know the reason why?<br /> > <br
/>>Because the KnownAssignedXIDs and lock tables on the standby need to<br />> be large enough to contain the
largestsnapshot and greatest number of<br />> AccessExclusiveLocks that could exist on the master at any given
time.<br/> > <br />>> I think this restriction obstructs making a flexible load balancing.<br />>> I'd
liketo make standby database to use load balancing.Of course<br />>> a role of a standby server is different from
oneof a master server.<br /> >> So I think it it natural that I want to set standby.max_connections less<br
/>>>than<br />>> primary.max_connections.<br />> <br />> Your load balancer should probably have a
configurationsetting that<br /> > controls how many connections it will try to make to the database, and<br />>
youcan set that to a lower value than max_connections.<br />> <br />Hi Robert.<br /><br />I understand the reason
Whystandby.max_connections must be higher<br /> than primary.max_connections.<br /><br />I'll try to restrict sessions
byload balancer.<br /><br />Thanks.<br /></div><div class="gmail_extra"><br /><br /><div class="gmail_quote">2013/12/11
RobertHaas <span dir="ltr"><<a href="mailto:robertmhaas@gmail.com"
target="_blank">robertmhaas@gmail.com</a>></span><br/><blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px#ccc solid;padding-left:1ex"><div class="im">On Tue, Dec 10, 2013 at 3:34 AM, 山田聡 <<a
href="mailto:satoshi.yamada.pg@gmail.com">satoshi.yamada.pg@gmail.com</a>>wrote:<br /> > Hello hackers.<br />
><br/> > I am struggling to understand why standby.max_connections must be higher<br /> > than<br /> > <a
href="http://primary.max_connections.Do"target="_blank">primary.max_connections.Do</a> someone know the reason why?<br
/><br/></div>Because the KnownAssignedXIDs and lock tables on the standby need to<br /> be large enough to contain the
largestsnapshot and greatest number of<br /> AccessExclusiveLocks that could exist on the master at any given time.<br
/><divclass="im"><br /> > I think this restriction obstructs making a flexible load balancing.<br /> > I'd like
tomake standby database to use load balancing.Of course<br /> > a role of a standby server is different from one of
amaster server.<br /> > So I think it it natural that I want to set standby.max_connections less<br /> > than<br
/>> primary.max_connections.<br /><br /></div>Your load balancer should probably have a configuration setting
that<br/> controls how many connections it will try to make to the database, and<br /> you can set that to a lower
valuethan max_connections.<br /><span class="HOEnZb"><font color="#888888"><br /> --<br /> Robert Haas<br />
EnterpriseDB:<a href="http://www.enterprisedb.com" target="_blank">http://www.enterprisedb.com</a><br /> The Enterprise
PostgreSQLCompany<br /></font></span></blockquote></div><br /></div>