Re: Dead Space Map version 2

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Heikki Linnakangas <heikki(at)enterprisedb(dot)com>
Cc: "Jim C(dot) Nasby" <jim(at)nasby(dot)net>, ITAGAKI Takahiro <itagaki(dot)takahiro(at)oss(dot)ntt(dot)co(dot)jp>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Dead Space Map version 2
Date: 2007-02-28 05:34:51
Message-ID: 25502.1172640891@sss.pgh.pa.us
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers pgsql-patches pgsql-performance

Heikki Linnakangas <heikki(at)enterprisedb(dot)com> writes:
> Tom Lane wrote:
>> I'd be happier if the DSM content could be
>> treated as just a hint.

> If we don't have a frozen state, we can't use the DSM to implement
> index-only scans.

To implement index-only scans, the DSM would have to be expected to
provide 100% reliable coverage, which will increase its cost and
complexity by orders of magnitude. If you insist on that, I will bet
you lunch at a fine restaurant that it doesn't make it into 8.3.

regards, tom lane

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Kris Jurka 2007-02-28 05:42:35 Re: [HACKERS] 5 Weeks till feature freeze or (do you know where your patch is?)
Previous Message Joshua D. Drake 2007-02-28 05:27:07 Re: [HACKERS] 5 Weeks till feature freeze or (do you know where your patch is?)

Browse pgsql-patches by date

  From Date Subject
Next Message Tom Lane 2007-02-28 06:02:33 Re: [HACKERS]
Previous Message Tom Lane 2007-02-28 05:21:21 Re: POSIX shared memory support

Browse pgsql-performance by date

  From Date Subject
Next Message ITAGAKI Takahiro 2007-02-28 06:04:09 Re: Dead Space Map version 2
Previous Message Geoff Tolley 2007-02-27 23:42:36 Re: Opinions on Raid