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Posted to modperl@perl.apache.org by Tim Bunce <Ti...@ig.co.uk> on 2000/06/04 21:37:42 UTC
Re: [benchmark] DBI/preload (was Re: [RFC] improving memory mapping
thru code exercising)
On Sat, Jun 03, 2000 at 02:49:47AM +0300, Stas Bekman wrote:
> On Fri, 2 Jun 2000, Perrin Harkins wrote:
>
> > On Sat, 3 Jun 2000, Stas Bekman wrote:
> > > * install_driver (2):
> > > DBI->install_driver("mysql");
> >
> > I've never seen that before,
>
> There is always a first time :)
>
> > and it isn't in the DBI perldoc.
>
> Where do you think I've found it :) It is mentioned in DBI manpage:
>
> DBI->connect automatically installs the driver if it
> has not been installed yet. Driver installation always
> returns a valid driver handle or it dies with an error
> message which includes the string 'install_driver' and
> the underlying problem. So, DBI->connect will die on a
> driver installation failure and will only return undef
> on a connect failure, for which $DBI::errstr will hold
> the error.
I've been meaning to document it properly for the last couple of
years, since I knew people were using it for mod_perl.
> but actualy it's the DBD:: method.
Nope. A DBI->method.
> > Is it safer than "use DBD::mysql;"?
>
> "safer" is the wrong question. It's always used by DBI, but when you call
> it at the server startup you get a few more K shared, compared with only
> preloading of DBD::mysql.
Yes, and the semantics of install_driver are that it'll die if the driver
can't be installed, just like 'use'.
> Apache::DBI->connect_on_init('DBI:mysql:test::localhost', [...]
> or DBI->disconnect("Cannot connect to database: $DBI::errstr\n");
There's no such method as DBI->disconnect.
Tim.
Re: [benchmark] DBI/preload (was Re: [RFC] improving memory mapping thru code exercising)
Posted by Jason Terry <jt...@g-web.net>.
I just wanted to thank you guys for sending this to the mailing list.
I added these lines to my startup script....
use Carp;
CGI->compile(qw(my_common_functions));
DBI->install_driver('mysql');
Please note that these were already existing in my startup script.
use CGI();
use DBI();
And after testing, and running the server with the new settings all night long, it seems that I am saving ~2M of RAM for each apache
process. Again thank you.
However, this has made me curious, and left me wondering... I have 3 scripts that I pre-load in my startup file, would any of my
self-made modules, or other CPAN modules, benefit from including directly in the startup script... as opposed to being loaded only
in the pre-loaded scripts themselves?
Again, thank you for this thread it has saved me 20-80M of RAM depending on my current load.
-Jason
----- Original Message -----
From: "Stas Bekman" <sb...@stason.org>
To: "Tim Bunce" <Ti...@ig.co.uk>
Cc: "mod_perl list" <mo...@apache.org>
Sent: Sunday, June 04, 2000 1:50 PM
Subject: Re: [benchmark] DBI/preload (was Re: [RFC] improving memory mapping thru code exercising)
> On Sun, 4 Jun 2000, Tim Bunce wrote:
>
> > On Sat, Jun 03, 2000 at 02:49:47AM +0300, Stas Bekman wrote:
> > > On Fri, 2 Jun 2000, Perrin Harkins wrote:
> > >
> > > > On Sat, 3 Jun 2000, Stas Bekman wrote:
> > > > > * install_driver (2):
> > > > > DBI->install_driver("mysql");
> > > >
> > > > I've never seen that before,
> > >
> > > There is always a first time :)
> > >
> > > > and it isn't in the DBI perldoc.
> > >
> > > Where do you think I've found it :) It is mentioned in DBI manpage:
> > >
> > > DBI->connect automatically installs the driver if it
> > > has not been installed yet. Driver installation always
> > > returns a valid driver handle or it dies with an error
> > > message which includes the string 'install_driver' and
> > > the underlying problem. So, DBI->connect will die on a
> > > driver installation failure and will only return undef
> > > on a connect failure, for which $DBI::errstr will hold
> > > the error.
> >
> > I've been meaning to document it properly for the last couple of
> > years, since I knew people were using it for mod_perl.
>
> I guess most of the mod_perl folks don't use it, since they don't
> know about it. I have discovered it following the Vivek's reply.
>
> > > but actualy it's the DBD:: method.
> >
> > Nope. A DBI->method.
>
> Ok
>
> > > > Is it safer than "use DBD::mysql;"?
> > >
> > > "safer" is the wrong question. It's always used by DBI, but when you call
> > > it at the server startup you get a few more K shared, compared with only
> > > preloading of DBD::mysql.
> >
> > Yes, and the semantics of install_driver are that it'll die if the driver
> > can't be installed, just like 'use'.
> >
> > > Apache::DBI->connect_on_init('DBI:mysql:test::localhost', [...]
> > > or DBI->disconnect("Cannot connect to database: $DBI::errstr\n");
> >
> > There's no such method as DBI->disconnect.
>
> Ouch, you are right. But the first part has never failed for me, so I copy
> and paste this old error for years :) Thanks for telling me!
>
> _____________________________________________________________________
> Stas Bekman JAm_pH -- Just Another mod_perl Hacker
> http://stason.org/ mod_perl Guide http://perl.apache.org/guide
> mailto:stas@stason.org http://perl.org http://stason.org/TULARC
> http://singlesheaven.com http://perlmonth.com http://sourcegarden.org
Re: [benchmark] DBI/preload (was Re: [RFC] improving memory mapping thru code exercising)
Posted by Stas Bekman <sb...@stason.org>.
On Sun, 4 Jun 2000, Tim Bunce wrote:
> On Sat, Jun 03, 2000 at 02:49:47AM +0300, Stas Bekman wrote:
> > On Fri, 2 Jun 2000, Perrin Harkins wrote:
> >
> > > On Sat, 3 Jun 2000, Stas Bekman wrote:
> > > > * install_driver (2):
> > > > DBI->install_driver("mysql");
> > >
> > > I've never seen that before,
> >
> > There is always a first time :)
> >
> > > and it isn't in the DBI perldoc.
> >
> > Where do you think I've found it :) It is mentioned in DBI manpage:
> >
> > DBI->connect automatically installs the driver if it
> > has not been installed yet. Driver installation always
> > returns a valid driver handle or it dies with an error
> > message which includes the string 'install_driver' and
> > the underlying problem. So, DBI->connect will die on a
> > driver installation failure and will only return undef
> > on a connect failure, for which $DBI::errstr will hold
> > the error.
>
> I've been meaning to document it properly for the last couple of
> years, since I knew people were using it for mod_perl.
I guess most of the mod_perl folks don't use it, since they don't
know about it. I have discovered it following the Vivek's reply.
> > but actualy it's the DBD:: method.
>
> Nope. A DBI->method.
Ok
> > > Is it safer than "use DBD::mysql;"?
> >
> > "safer" is the wrong question. It's always used by DBI, but when you call
> > it at the server startup you get a few more K shared, compared with only
> > preloading of DBD::mysql.
>
> Yes, and the semantics of install_driver are that it'll die if the driver
> can't be installed, just like 'use'.
>
> > Apache::DBI->connect_on_init('DBI:mysql:test::localhost', [...]
> > or DBI->disconnect("Cannot connect to database: $DBI::errstr\n");
>
> There's no such method as DBI->disconnect.
Ouch, you are right. But the first part has never failed for me, so I copy
and paste this old error for years :) Thanks for telling me!
_____________________________________________________________________
Stas Bekman JAm_pH -- Just Another mod_perl Hacker
http://stason.org/ mod_perl Guide http://perl.apache.org/guide
mailto:stas@stason.org http://perl.org http://stason.org/TULARC
http://singlesheaven.com http://perlmonth.com http://sourcegarden.org