| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Alvaro Herrera <alvherre(at)commandprompt(dot)com> |
| Cc: | Oleg Bartunov <oleg(at)sai(dot)msu(dot)su>, Teodor Sigaev <teodor(at)sigaev(dot)ru>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: More fun with GIN lossy-page pointers |
| Date: | 2010-08-01 01:38:33 |
| Message-ID: | 23039.1280626713@sss.pgh.pa.us |
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| Lists: | pgsql-hackers |
Alvaro Herrera <alvherre(at)commandprompt(dot)com> writes:
> Excerpts from Tom Lane's message of sb 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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