Re: RIGHT/FULL OUTER hash joins (was Re: small table left outer join big table) - Mailing list pgsql-hackers

From Tom Lane
Subject Re: RIGHT/FULL OUTER hash joins (was Re: small table left outer join big table)
Date
Msg-id 18600.1293726905@sss.pgh.pa.us
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In response to Re: RIGHT/FULL OUTER hash joins (was Re: small table left outer join big table)  (Robert Haas <robertmhaas@gmail.com>)
List pgsql-hackers
Robert Haas <robertmhaas@gmail.com> writes:
> On Thu, Dec 30, 2010 at 10:45 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> ... But we only need one bit, so what about commandeering
>> an infomask bit in the tuple itself? �For the initial implementation
>> I'd be inclined to take one of the free bits in t_infomask2. �We could
>> actually get away with overlaying the flag bit with one of the tuple
>> visibility bits, since it will only be used in tuples that are in the
>> in-memory hash table, which don't need visibility info anymore. �But
>> that seems like a kluge that could wait until we really need the flag
>> space.

> I think that's a reasonable approach, although I might be inclined to
> do the overlay sooner rather than later if it doesn't add too much
> complexity.

Well, there's no "complexity" involved, it's just which bit do we define
the macro as.  Any complexity is conceptual.
        regards, tom lane


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