Re: [COMMITTERS] pgsql: Don't generate parallel paths for rels with parallel-restricted

<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Thu, Jun 9, 2016 at 11:38 PM, Tom Lane <<a
href="mailto:tgl@sss.pgh.pa.us">tgl@sss.pgh.pa.us</a>>wrote:<br />><br />> Robert Haas <<a
href="mailto:robertmhaas@gmail.com">robertmhaas@gmail.com</a>>writes:<br />><br />> > Could you answer my
questionabout whether adjust_appendrel_attrs()<br />> > might translate Vars into non-Vars?<br />><br />>
Yes,absolutely.<br /><br />Isn't this true only for UNION ALL cases and not for inheritance child relations (at least
thatis what seems to be mentioned in comments for translated_vars in AppendRelInfo)?   If that is right, then I think
thereshouldn't be a problem w.r.t parallel plans even if adjust_appendrel_attrs() translate Vars into non-Vars, because
forUNION ALL it seems parent rels rtekind is RTE_SUBQUERY and we consider such rels as parallel unsafe (see
set_rel_consider_parallel()). So it doesn't matter even if child rels target list contains any parallel unsafe
expression,as we are not going to create parallel paths for such relations.</div><div class="gmail_quote"><br
/></div><divclass="gmail_quote"><br />With Regards,<br />Amit Kapila.<br />EnterpriseDB: <a
href="http://www.enterprisedb.com/"target="_blank">http://www.enterprisedb.com</a><br /></div></div></div>