| From: | Decibel! <decibel(at)decibel(dot)org> |
|---|---|
| To: | Gregory Stark <stark(at)enterprisedb(dot)com> |
| Cc: | "Neil Conway" <neilc(at)samurai(dot)com>, "pgsql-hackers list" <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: EXPLAIN ANALYZE printing logical and hardware I/O per-node |
| Date: | 2007-12-19 01:17:53 |
| Message-ID: | 43DDC985-FC7C-4DA2-A576-9CDB0C63FAFF@decibel.org |
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| Thread: | |
| Lists: | pgsql-hackers |
On Dec 18, 2007, at 3:32 AM, Gregory Stark wrote:
>> Also, has anyone looked into adding a class of system calls that
>> would
>> actually tell us if the kernel issued physical IO? I find it hard
>> to believe
>> that other RDBMSes wouldn't like to have that info...
>
> Yeah, I think that's called "DTrace"
That seems like way overkill...
When a read() call returns, surely the kernel knows whether it
actually issued a physical read request to satisfy that. I don't see
any reason why you couldn't have a version of read() that returns
that information. I also rather doubt that we're the only userland
software that would make use of that.
--
Decibel!, aka Jim C. Nasby, Database Architect decibel(at)decibel(dot)org
Give your computer some brain candy! www.distributed.net Team #1828
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