Re: [Dbix-class] Caching a resultset?
On Sun, Jan 13, 2013 at 11:35:06PM -0500, Jesse Sheidlower wrote:
I have a Catalyst app that very frequently (pretty much every request)
requires several DBIC resultsets that return a small number of values,
that very rarely change. I'm trying to cache this, so I can update the
cache when the values change and not have to hit my DB a half-dozen
times on every request for data that is effectively static.
Originally the relevant line was along the lines of:
$c-stash-{subjects} = $c-model('WordsDB::Subject')-search();
I replaced this, following the C::P::Cache docs, with
unless ( $c-stash-{subjects} = $cache-get( 'subjects' ) ) {
$c-stash-{subjects} =
$c-model('WordsDB::Subject')-search();
$cache-set( 'subject', $c-stash-{subjects} );
}
However, this dies (on a second run, when it's actually hitting the
cache) with undef error - Can't call method select on an undefined
value at /usr/share/perl5/DBIx/Class/ResultSet.pm line 957.
This is a crappy error message. Please tell us which DBIC version are
you running exactly so that we can figure out what is on this line.
So I'm assuming that I can't just stuff a RS into the cache and expect
it to work.
Things should just work, at least for Storable-based serialization. Need
more details to diagnose this.
___
List: http://lists.scsys.co.uk/cgi-bin/mailman/listinfo/dbix-class
IRC: irc.perl.org#dbix-class
SVN: http://dev.catalyst.perl.org/repos/bast/DBIx-Class/
Searchable Archive: http://www.grokbase.com/group/dbix-class@lists.scsys.co.uk
Re: [Dbix-class] Caching a resultset?
On Mon, Jan 14, 2013 at 09:26:04AM +0100, Alexander Hartmaier wrote: The resultset has a ref to the schema which in turn has one to its database connection which can't be serialized/cached. After unfreezing it you have to link the $rs back to a schema with a working database connection. I wasn't able to find this in the docs although I'm pretty sure I've read it sometimes. It is at a crappy place in the docs[1][2], but the error message that was supposed to print is pretty comprehensive[3]. Obviously improving the docs is never a bad idea. [1] https://metacpan.org/module/DBIx::Class::ResultSourceHandle#STORABLE_thaw [2] https://metacpan.org/module/DBIx::Class::Schema#thaw [3] https://metacpan.org/source/GETTY/DBIx-Class-0.08204/lib/DBIx/Class/ResultSource.pm#L1132 Cheers ___ List: http://lists.scsys.co.uk/cgi-bin/mailman/listinfo/dbix-class IRC: irc.perl.org#dbix-class SVN: http://dev.catalyst.perl.org/repos/bast/DBIx-Class/ Searchable Archive: http://www.grokbase.com/group/dbix-class@lists.scsys.co.uk
Re: [Dbix-class] Caching a resultset?
On Mon, Jan 14, 2013 at 10:13:44PM +1100, Peter Rabbitson wrote:
On Sun, Jan 13, 2013 at 11:35:06PM -0500, Jesse Sheidlower wrote:
I have a Catalyst app that very frequently (pretty much every request)
requires several DBIC resultsets that return a small number of values,
that very rarely change. I'm trying to cache this, so I can update the
cache when the values change and not have to hit my DB a half-dozen
times on every request for data that is effectively static.
Originally the relevant line was along the lines of:
$c-stash-{subjects} = $c-model('WordsDB::Subject')-search();
I replaced this, following the C::P::Cache docs, with
unless ( $c-stash-{subjects} = $cache-get( 'subjects' ) ) {
$c-stash-{subjects} =
$c-model('WordsDB::Subject')-search();
$cache-set( 'subject', $c-stash-{subjects} );
}
However, this dies (on a second run, when it's actually hitting the
cache) with undef error - Can't call method select on an undefined
value at /usr/share/perl5/DBIx/Class/ResultSet.pm line 957.
This is a crappy error message. Please tell us which DBIC version are
you running exactly so that we can figure out what is on this line.
It's version 0.08196. This is in the cursor() method.
So I'm assuming that I can't just stuff a RS into the cache and expect
it to work.
Things should just work, at least for Storable-based serialization. Need
more details to diagnose this.
What would you like to know?
Jesse Sheidlower
___
List: http://lists.scsys.co.uk/cgi-bin/mailman/listinfo/dbix-class
IRC: irc.perl.org#dbix-class
SVN: http://dev.catalyst.perl.org/repos/bast/DBIx-Class/
Searchable Archive: http://www.grokbase.com/group/dbix-class@lists.scsys.co.uk
Re: [Dbix-class] Caching a resultset?
On Mon, Jan 14, 2013 at 06:30:42AM -0500, Jesse Sheidlower wrote:
On Mon, Jan 14, 2013 at 10:13:44PM +1100, Peter Rabbitson wrote:
On Sun, Jan 13, 2013 at 11:35:06PM -0500, Jesse Sheidlower wrote:
I have a Catalyst app that very frequently (pretty much every request)
requires several DBIC resultsets that return a small number of values,
that very rarely change. I'm trying to cache this, so I can update the
cache when the values change and not have to hit my DB a half-dozen
times on every request for data that is effectively static.
Originally the relevant line was along the lines of:
$c-stash-{subjects} = $c-model('WordsDB::Subject')-search();
I replaced this, following the C::P::Cache docs, with
unless ( $c-stash-{subjects} = $cache-get( 'subjects' ) ) {
$c-stash-{subjects} =
$c-model('WordsDB::Subject')-search();
$cache-set( 'subject', $c-stash-{subjects} );
}
What is $cache being serialized via? Storable? Or some other scheme?
However, this dies (on a second run, when it's actually hitting the
cache) with undef error - Can't call method select on an undefined
value at /usr/share/perl5/DBIx/Class/ResultSet.pm line 957.
What is the exact code from get()ing the cache value to the error (or
what is the smallest piece of code you can reduce it to)?
Cheers
___
List: http://lists.scsys.co.uk/cgi-bin/mailman/listinfo/dbix-class
IRC: irc.perl.org#dbix-class
SVN: http://dev.catalyst.perl.org/repos/bast/DBIx-Class/
Searchable Archive: http://www.grokbase.com/group/dbix-class@lists.scsys.co.uk
Re: [Dbix-class] Caching a resultset?
On Mon, Jan 14, 2013 at 11:06:56PM +1100, Peter Rabbitson wrote:
On Mon, Jan 14, 2013 at 06:30:42AM -0500, Jesse Sheidlower wrote:
On Mon, Jan 14, 2013 at 10:13:44PM +1100, Peter Rabbitson wrote:
On Sun, Jan 13, 2013 at 11:35:06PM -0500, Jesse Sheidlower wrote:
I have a Catalyst app that very frequently (pretty much every request)
requires several DBIC resultsets that return a small number of values,
that very rarely change. I'm trying to cache this, so I can update the
cache when the values change and not have to hit my DB a half-dozen
times on every request for data that is effectively static.
Originally the relevant line was along the lines of:
$c-stash-{subjects} = $c-model('WordsDB::Subject')-search();
I replaced this, following the C::P::Cache docs, with
unless ( $c-stash-{subjects} = $cache-get( 'subjects' ) ) {
$c-stash-{subjects} =
$c-model('WordsDB::Subject')-search();
$cache-set( 'subject', $c-stash-{subjects} );
}
What is $cache being serialized via? Storable? Or some other scheme?
I'm using Cache::FastMmap, which uses Storable (unless you flip a switch
to have it store values as raw binary data; I didn't flip this switch).
However, this dies (on a second run, when it's actually hitting the
cache) with undef error - Can't call method select on an undefined
value at /usr/share/perl5/DBIx/Class/ResultSet.pm line 957.
What is the exact code from get()ing the cache value to the error (or
what is the smallest piece of code you can reduce it to)?
It's in a Catalyst context, so there's a ton of stuff in between, but
the core is that I put the RS into the Catalyst stash as indicated
above, and then in a template I have:
[% WHILE ( subject = subjects.next ) %]
option value=[% subject.id %][% subject %]/option
[% END %]
Thanks.
___
List: http://lists.scsys.co.uk/cgi-bin/mailman/listinfo/dbix-class
IRC: irc.perl.org#dbix-class
SVN: http://dev.catalyst.perl.org/repos/bast/DBIx-Class/
Searchable Archive: http://www.grokbase.com/group/dbix-class@lists.scsys.co.uk
Re: [Dbix-class] Caching a resultset?
On Sun, Jan 13, 2013 at 11:35:06PM -0500, Jesse Sheidlower wrote:
I have a Catalyst app that very frequently (pretty much every request)
requires several DBIC resultsets that return a small number of values,
that very rarely change. I'm trying to cache this, so I can update the
cache when the values change and not have to hit my DB a half-dozen
times on every request for data that is effectively static.
Originally the relevant line was along the lines of:
$c-stash-{subjects} = $c-model('WordsDB::Subject')-search();
I replaced this, following the C::P::Cache docs, with
unless ( $c-stash-{subjects} = $cache-get( 'subjects' ) ) {
$c-stash-{subjects} =
$c-model('WordsDB::Subject')-search();
$cache-set( 'subject', $c-stash-{subjects} );
}
However, this dies (on a second run, when it's actually hitting the
cache) with undef error - Can't call method select on an undefined
value at /usr/share/perl5/DBIx/Class/ResultSet.pm line 957. So I'm
assuming that I can't just stuff a RS into the cache and expect it to
work. Is there an easy way around it? (I know I could retrieve the
actual data and put that into the cache, but then I'd have to rewrite a
whole bunch of templates, that are expecting a resultset.)
Thanks.
So apart from the mystery around the nonsensical exception - does this help?
local $DBIx::Class::ResultSourceHandle::thaw_schema = $c-model(...)-schema;
Cheers
___
List: http://lists.scsys.co.uk/cgi-bin/mailman/listinfo/dbix-class
IRC: irc.perl.org#dbix-class
SVN: http://dev.catalyst.perl.org/repos/bast/DBIx-Class/
Searchable Archive: http://www.grokbase.com/group/dbix-class@lists.scsys.co.uk
[Dbix-class] Review request - branch for_current/cumulative
Please review and if no issues found merge [1]. More stuff will be coming down the pipe in the next few days... hopefully. [1] https://github.com/dbsrgits/dbix-class/compare/master...for_current;cumulative ___ List: http://lists.scsys.co.uk/cgi-bin/mailman/listinfo/dbix-class IRC: irc.perl.org#dbix-class SVN: http://dev.catalyst.perl.org/repos/bast/DBIx-Class/ Searchable Archive: http://www.grokbase.com/group/dbix-class@lists.scsys.co.uk
Re: [Dbix-class] Caching a resultset?
One problem I see with the exact code posted here is a typo referring to
singular-vs-plural on the hash key:
On Sun, Jan 13, 2013 at 10:35 PM, Jesse Sheidlower jes...@panix.com wrote:
unless ( $c-stash-{subjects} = $cache-get( 'subjects' ) ) {
$c-stash-{subjects} =
$c-model('WordsDB::Subject')-search();
$cache-set( 'subject', $c-stash-{subjects} );
}
Note 'subject' vs 'subjects':
$cache-set( 'subject', $c-stash-{subjects} );
--
Will Trillich :: 812.454.6431
“Grading takes away all the fun from failing. And a huge part of education
is about failure.” -- Shimon Schocken
___
List: http://lists.scsys.co.uk/cgi-bin/mailman/listinfo/dbix-class
IRC: irc.perl.org#dbix-class
SVN: http://dev.catalyst.perl.org/repos/bast/DBIx-Class/
Searchable Archive: http://www.grokbase.com/group/dbix-class@lists.scsys.co.uk
Re: [Dbix-class] Caching a resultset?
On Mon, Jan 14, 2013 at 09:41:45AM -0600, will trillich wrote:
One problem I see with the exact code posted here is a typo referring to
singular-vs-plural on the hash key:
On Sun, Jan 13, 2013 at 10:35 PM, Jesse Sheidlower jes...@panix.com wrote:
unless ( $c-stash-{subjects} = $cache-get( 'subjects' ) ) {
$c-stash-{subjects} =
$c-model('WordsDB::Subject')-search();
$cache-set( 'subject', $c-stash-{subjects} );
}
Note 'subject' vs 'subjects':
$cache-set( 'subject', $c-stash-{subjects} );
That was my typo re-keying the actual code for the mailing list, the
original (which presents it differently, in a way not relevant for this
purpose) is correct. Sorry for the misleading example.
Jesse
___
List: http://lists.scsys.co.uk/cgi-bin/mailman/listinfo/dbix-class
IRC: irc.perl.org#dbix-class
SVN: http://dev.catalyst.perl.org/repos/bast/DBIx-Class/
Searchable Archive: http://www.grokbase.com/group/dbix-class@lists.scsys.co.uk
Re: [Dbix-class] Caching a resultset?
On Tue, Jan 15, 2013 at 01:30:55AM +1100, Peter Rabbitson wrote:
On Sun, Jan 13, 2013 at 11:35:06PM -0500, Jesse Sheidlower wrote:
I have a Catalyst app that very frequently (pretty much every request)
requires several DBIC resultsets that return a small number of values,
that very rarely change. I'm trying to cache this, so I can update the
cache when the values change and not have to hit my DB a half-dozen
times on every request for data that is effectively static.
Originally the relevant line was along the lines of:
$c-stash-{subjects} = $c-model('WordsDB::Subject')-search();
I replaced this, following the C::P::Cache docs, with
unless ( $c-stash-{subjects} = $cache-get( 'subjects' ) ) {
$c-stash-{subjects} =
$c-model('WordsDB::Subject')-search();
$cache-set( 'subject', $c-stash-{subjects} );
}
However, this dies (on a second run, when it's actually hitting the
cache) with undef error - Can't call method select on an undefined
value at /usr/share/perl5/DBIx/Class/ResultSet.pm line 957. So I'm
assuming that I can't just stuff a RS into the cache and expect it to
work. Is there an easy way around it? (I know I could retrieve the
actual data and put that into the cache, but then I'd have to rewrite a
whole bunch of templates, that are expecting a resultset.)
Thanks.
So apart from the mystery around the nonsensical exception - does this help?
local $DBIx::Class::ResultSourceHandle::thaw_schema = $c-model(...)-schema;
Yes! Putting that before the unless seems to make everything work
correctly Will be testing further this afternoon. Thanks!
Does this need to be documented somewhere, or does something need to be
fixed, or...?
Jesse
___
List: http://lists.scsys.co.uk/cgi-bin/mailman/listinfo/dbix-class
IRC: irc.perl.org#dbix-class
SVN: http://dev.catalyst.perl.org/repos/bast/DBIx-Class/
Searchable Archive: http://www.grokbase.com/group/dbix-class@lists.scsys.co.uk
Re: [Dbix-class] Caching a resultset?
On Mon, Jan 14, 2013 at 11:07:34AM -0500, Jesse Sheidlower wrote:
On Tue, Jan 15, 2013 at 01:30:55AM +1100, Peter Rabbitson wrote:
On Sun, Jan 13, 2013 at 11:35:06PM -0500, Jesse Sheidlower wrote:
I have a Catalyst app that very frequently (pretty much every request)
requires several DBIC resultsets that return a small number of values,
that very rarely change. I'm trying to cache this, so I can update the
cache when the values change and not have to hit my DB a half-dozen
times on every request for data that is effectively static.
Originally the relevant line was along the lines of:
$c-stash-{subjects} = $c-model('WordsDB::Subject')-search();
I replaced this, following the C::P::Cache docs, with
unless ( $c-stash-{subjects} = $cache-get( 'subjects' ) ) {
$c-stash-{subjects} =
$c-model('WordsDB::Subject')-search();
$cache-set( 'subject', $c-stash-{subjects} );
}
However, this dies (on a second run, when it's actually hitting the
cache) with undef error - Can't call method select on an undefined
value at /usr/share/perl5/DBIx/Class/ResultSet.pm line 957. So I'm
assuming that I can't just stuff a RS into the cache and expect it to
work. Is there an easy way around it? (I know I could retrieve the
actual data and put that into the cache, but then I'd have to rewrite a
whole bunch of templates, that are expecting a resultset.)
Thanks.
So apart from the mystery around the nonsensical exception - does this help?
local $DBIx::Class::ResultSourceHandle::thaw_schema =
$c-model(...)-schema;
Yes! Putting that before the unless seems to make everything work
correctly Will be testing further this afternoon. Thanks!
Please let me know if wider testing is succesful.
Does this need to be documented somewhere, or does something need to be
fixed, or...?
Please see [1]. There are really two problems:
1) the exception thrown was supposed to be [2]. This part is a bug, and
I can't yet figure out what is causing it. The test at [3] is nearly
identical, and behaves correctly. Any thoughts on why yours failed
(perhaps a debugger walk) would be more than welcome.
2) The docs suck (again as per [1]) and would welcome imrpovements. Also
adding stuff to C::P::Cache won't hurt either.
Cheers
[1] http://lists.scsys.co.uk/pipermail/dbix-class/2013-January/011040.html
[2]
https://metacpan.org/source/GETTY/DBIx-Class-0.08204/lib/DBIx/Class/ResultSource.pm#L1132
[3] https://metacpan.org/source/GETTY/DBIx-Class-0.08204/t/84serialize.t#L199
___
List: http://lists.scsys.co.uk/cgi-bin/mailman/listinfo/dbix-class
IRC: irc.perl.org#dbix-class
SVN: http://dev.catalyst.perl.org/repos/bast/DBIx-Class/
Searchable Archive: http://www.grokbase.com/group/dbix-class@lists.scsys.co.uk
