Re: More fun with GIN lossy-page pointers - Mailing list pgsql-hackers

From Tom Lane
Subject Re: More fun with GIN lossy-page pointers
Date
Msg-id 23039.1280626713@sss.pgh.pa.us
Whole thread Raw
In response to Re: More fun with GIN lossy-page pointers  (Alvaro Herrera <alvherre@commandprompt.com>)
List pgsql-hackers
Alvaro Herrera <alvherre@commandprompt.com> writes:
> Excerpts from Tom Lane's message of sáb jul 31 09:57:13 -0400 2010:
>> So far as I can see, it's impossible to handle this situation when
>> examining only one TID per stream with no lookahead.  Choosing to
>> advance the second stream would obviously fail in many other cases,
>> so there is no correct action.  The only reasonable way out is to
>> forbid the case --- that is, decree that a keystream may *not*
>> contain both lossy and nonlossy pointers to the same page.

> Would it make sense to order the streams differently?  I mean, what if
> whole-page pointers in the lossy stream are processed before regular ones?

Hmm ... interesting thought.  I'm not sure what the implications are,
but it's definitely worth considering.
        regards, tom lane


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