<div dir="ltr">>> Because the KnownAssignedXIDs and lock tables on the standby need to<br />>> be large
enoughto contain the largest snapshot and greatest number of<br />>> AccessExclusiveLocks that could exist on the
masterat any given time.<br /> > <br />> Right. Initially during the development of Hot Standby, it looked
like<br/>> the "max_connections >= master's" requirement on standbys wasn't going<br />> to be necessary, or
couldbe avoided. However, Simon gave up on that<br /> > idea on pragmatic grounds here:<br />> <br />> <a
href="http://www.postgresql.org/message-id/1252002165.2889.467.camel@ebony.2ndQuadrant">http://www.postgresql.org/message-id/1252002165.2889.467.camel@ebony.2ndQuadrant</a><br
/>> <br />> I'd thought about revisiting this myself, but I think that the impetus<br />> to do so is lessened
byrecent work on logical replication.<br />> <br /><br />Hi Peter<br /><br />Your information make my question be
clearly.<br/> I understand the discussions about this restriction.<br /><br />Thanks.<br /><br /></div><div
class="gmail_extra"><br/><br /><div class="gmail_quote">2013/12/12 Peter Geoghegan <span dir="ltr"><<a
href="mailto:pg@heroku.com"target="_blank">pg@heroku.com</a>></span><br /><blockquote class="gmail_quote"
style="margin:00 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="im">On Tue, Dec 10, 2013 at 1:17 PM,
RobertHaas <<a href="mailto:robertmhaas@gmail.com">robertmhaas@gmail.com</a>> wrote:<br /> > Because the
KnownAssignedXIDsand lock tables on the standby need to<br /> > be large enough to contain the largest snapshot and
greatestnumber of<br /> > AccessExclusiveLocks that could exist on the master at any given time.<br /><br
/></div>Right.Initially during the development of Hot Standby, it looked like<br /> the "max_connections >=
master's"requirement on standbys wasn't going<br /> to be necessary, or could be avoided. However, Simon gave up on
that<br/> idea on pragmatic grounds here:<br /><br /><a
href="http://www.postgresql.org/message-id/1252002165.2889.467.camel@ebony.2ndQuadrant"
target="_blank">http://www.postgresql.org/message-id/1252002165.2889.467.camel@ebony.2ndQuadrant</a><br/><br /> I'd
thoughtabout revisiting this myself, but I think that the impetus<br /> to do so is lessened by recent work on logical
replication.<br/><span class="HOEnZb"><font color="#888888"><br /> --<br /> Peter Geoghegan<br
/></font></span></blockquote></div><br/></div>