whether I can see other alternative plantrees for one query?

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От 土卜皿
Тема whether I can see other alternative plantrees for one query?
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Msg-id CADT5_19ueAQVcKkPeMVbyH+LLiqs=_piogp-yGYkLnAfS3BqCw@mail.gmail.com
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Ответы Re: whether I can see other alternative plantrees for one query?  (Tom Lane <tgl@sss.pgh.pa.us>)
Re: whether I can see other alternative plantrees for one query?  (Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>)
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hi, all
  NOTE: Version is 8.4   Fedora 20 X86_64
 
  for understanding optimizer's internals, I

set debug_print_plan=on

and created two tables as follows :

create table Reserves (sid integer, bid integer,day date,rname char(25));
create table Sailors(sid integer,sname char(25),rating integer,age real);

and add 1,000,000 records for each.

and execute the cmd:

select S.rating,count(*)
         from Sailors S
         where S.rating > 5 and S.age = 20
         group by S.rating;

but from the log, I only found the final selected planTree, so I want to ask:
what should I do if I want to see the other alternative planTrees?  any advice will be apprecitaed!

Dillon Peng

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