Date: Tue, 24 Mar 1998 09:57:05 -0600 (CST) From: "Kent S. Gordon" <kgor@inetspace.com> To: eivind@yes.no Cc: shimon@simon-shapiro.org, roberto@keltia.freenix.fr, freebsd-hackers@FreeBSD.ORG Subject: Re: How do you increase available SYSV shared memory? Message-ID: <199803241557.JAA24709@soccer.inetspace.com> In-Reply-To: <19980320221931.51710@follo.net> (message from Eivind Eklund on Fri, 20 Mar 1998 22:19:31 %2B0100)
next in thread | previous in thread | raw e-mail | index | archive | help
>>>>> "eivind" == Eivind Eklund <eivind@yes.no> writes:
> On Fri, Mar 20, 1998 at 12:32:19PM -0800, Simon Shapiro wrote:
>> On 18-Mar-98 Kent S. Gordon wrote: > >>>>>> "shimon" == Simon
>> Shapiro <shimon@simon-shapiro.org> writes: > I have been
>> thinking of changing Postgres to use mmapped files instead > of
>> SYSV shared memory. I think this should allow for larger
>> postgres
>>
>> This will be a disaster. It assumes that PostgreSQL uses files
>> for data storage. While this is the default mode, it is NOT
>> the only storage meanager. In PostgreSQL, like most true
>> RDBMS, the storage of data is decoupled from the logic of the
>> relational model, etc. I am building a storage manager that
>> uses a totally different (distributed) storage model than Unix
>> files. A memory based storage manager already exists in
>> PostgreSQL. Please do not break these.
I am not going to change any of the storage manager code.
> I don't think you're quite getting him (or I'm not getting you
> at all). mmap()ing /dev/zero is a common way of getting hold of
> shared memory, instead of using the SYSV SHMEM extension.
> mmap'ing usually works better.
I probably will not be using /dev/zero, but yes I am just replacing
one method of getting shared memory with another way. It looks like
it will only impact less than 50 lines of postgres code.
> This is just replacing one technique for getting hold of shared
> memory with another; it does nothing to the storage manager.
> Eivind.
--
Kent S. Gordon
Architect
iNetSpace Co.
voice: (972)851-3494 fax:(972)702-0384 e-mail:kgor@inetspace.com
To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-hackers" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199803241557.JAA24709>