From: Robert Haas <robertmhaas@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Gregory Stark <stark@enterprisedb.com>
Cc: ITAGAKI Takahiro <itagaki.takahiro@oss.ntt.co.jp>
Cc: Postgres <pgsql-hackers@postgresql.org>
Subject: Re: posix_fadvise v22
Date: Thu, 1 Jan 2009 21:43:29 -0500
Message-ID: <603c8f070901011843p121e40afu35c4a7bdc51c051c@mail.gmail.com> (raw)
In-Reply-To: <10658.1230843315@sss.pgh.pa.us>
References: <FDDBA24E-FF4D-4654-BA75-692B3BA71B97@enterprisedb.com>
<8347.1229012970@sss.pgh.pa.us>
<4136ffa0812110911x4914a951o6ca502879e3dede7@mail.gmail.com>
<87k5a6tmy7.fsf@oxford.xeocode.com>
<603c8f070901011230t1afa6644racb715b975078054@mail.gmail.com>
<10658.1230843315@sss.pgh.pa.us>
On Thu, Jan 1, 2009 at 3:55 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> "Robert Haas" <robertmhaas@gmail.com> writes:
>> Am I correct in thinking that the only thing we're really checking for
>> here is whether a trivial posix_fadvise() call returns success? If
>> so, is this test really worth doing?
>
> Runtime tests performed during configure are generally a bad idea to
> start with --- it's impossible to do any such thing in a
> cross-compilation scenario, for example.
OK, here's an update of Greg's patch with the runtime configure test
ripped out, some minor documentation tweaks, and a few unnecessary
whitespace diff hunks quashed. I think this is about ready for
committer review. The only thing I haven't been able to do is
demonstrate that this change actually produces a performance
improvement. Either I'm testing the wrong thing, or it just doesn't
provide any benefit on a single-spindle system. However, I believe
that Greg has previously posted some fairly impressive performance
results, so I'm not sure that my shortcomings in this area should be a
bar to having a committer pick this one up. If more testing is
needed, it would at least be helpful to have a committer specify what
areas they are concerned about.
...Robert
Attachments:
posix_fadvise_v23_rh1.diff.gz (application/x-gzip, 11.8K) download
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To: pgsql-hackers@postgresql.org
Cc: robertmhaas@gmail.com, tgl@sss.pgh.pa.us, stark@enterprisedb.com, itagaki.takahiro@oss.ntt.co.jp
Subject: Re: posix_fadvise v22
In-Reply-To: <603c8f070901011843p121e40afu35c4a7bdc51c051c@mail.gmail.com>
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