Re: Proposal : Parallel Merge Join
Amit Kapila <amit.kapila16@gmail.com>
From: Amit Kapila <amit.kapila16@gmail.com>
To: Dilip Kumar <dilipbalaut@gmail.com>
Cc: Robert Haas <robertmhaas@gmail.com>,
pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2017-02-25T05:59:19Z
Lists: pgsql-hackers
On Fri, Feb 24, 2017 at 4:49 PM, Dilip Kumar <dilipbalaut@gmail.com> wrote: > On Fri, Feb 24, 2017 at 3:04 PM, Amit Kapila <amit.kapila16@gmail.com> wrote: >> What advantage do you see for considering such a path when the cost of >> innerpath is more than cheapest_total_inner? Remember the more paths >> we try to consider, the more time we spend in the planner. By any >> chance are you able to generate any query where it will give benefit >> by considering costlier innerpath? > > Changed > It seems you have forgotten to change in the below check: + if (innerpath != NULL && + innerpath->parallel_safe && + (cheapest_startup_inner == NULL || + cheapest_startup_inner->parallel_safe == false || + compare_path_costs(innerpath, cheapest_startup_inner, + STARTUP_COST) < 0)) + /* Found a cheap (or even-cheaper) sorted parallel safer path */ typo /safer/safe Note - Change the patch status in CF app (to Needs Review) whenever you post a new patch. I could see that your other patch also needs a similar update in CF app. -- With Regards, Amit Kapila. EnterpriseDB: http://www.enterprisedb.com
Commits
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Consider parallel merge joins.
- 3bc7dafa9beb 10.0 landed
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Preparatory refactoring for parallel merge join support.
- a71f10189dc1 10.0 landed
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Fix parallel hash join path search.
- 655393a022bd 10.0 landed