<div dir="ltr">It would make PostgreSQL too much like Oracle ;) Let's keep PostgreSQL simple and compact please.<br />I
preferapplications retest when migrating to new PostgreSQL version. In this case surprises happen then you expect them
notin some unforeseen point of time in the future.<br /> Keeping all this old functionality around will make
maintenanceand adding new stuff harder.<br />It also complicates tracking problems where in addition to db version you
needto find out what version it is supposed to emulate. <br /><br /><div class="gmail_quote">On Thu, Aug 7, 2008 at
5:17PM, Simon Riggs <span dir="ltr"><<a href="mailto:simon@2ndquadrant.com">simon@2ndquadrant.com</a>></span>
wrote:<br/><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex;
padding-left:1ex;"> Tom's recent changes to allow hash distinct (yay!) prompted something<br /> that I'd thought about
previously.<br/><br /> Subtle changes in the output of queries can force an application retest,<br /> which then can
slowdown or prevent an upgrade to the latest release. We<br /> always assume the upgrade itself is the problem, but the
biggestbarrier<br /> I see is the cost and delay involved in upgrading the application.<br /><br /> We could invent a
newparameter called enable_sort_distinct, but thats<br /> way too specific and horrible.<br /><br /> What I would like
isa parameter called sql_compatibility which has<br /> settings such as 8.3, 8.4 etc.. By default it would have the
value8.4,<br /> but for people that want to upgrade *without* retesting their<br /> application, they could set it to
8.3.<br/><br /> Every time we introduce a feature that changes output, we just put an if<br /> test in saying
sql_compatibility= X, (the release we added feature).<br /><br /> Straightforward, futureproof. Cool.<br /><br /> Not
foolproof,but still worth it. This would allow many users to<br /> upgrade to 8.4 for new features, yet without
changingapps.<br /><br /> --<br /> Simon Riggs <a href="http://www.2ndQuadrant.com"
target="_blank">www.2ndQuadrant.com</a><br/> PostgreSQL Training, Services and Support<br /><font color="#888888"><br
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