| From: | Dilip Kumar <dilipbalaut(at)gmail(dot)com> |
|---|---|
| To: | Robert Haas <robertmhaas(at)gmail(dot)com> |
| Cc: | Armor <yupengstone(at)qq(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: One question about transformation ANY Sublinks into joins |
| Date: | 2016-07-21 17:07:32 |
| Message-ID: | CAFiTN-u92gq_cXCCsbSw8oGYyd0T6T=N70fVmAG8w3g_9N1LVw@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Thu, Jul 21, 2016 at 9:53 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> It would need to be a Hash Semi Join rather than a Hash Join, wouldn't it?
I guess, Hash Join will do here,
because inner hash node is, on hash aggregate with group key on t2.id2,
t2.c2
and hash join condition is (t1.id1 = t2.id2) AND (t1.c1 = t2.c2).
So I think these together will make sure that we don't get duplicate tuple
for one outer record.
--
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com
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