1DBIx::Class::Manual::TrUosuebrleCsohnotortiibnugt(e3d)PDeBrIlx:D:oCcluamsesn:t:aMtainounal::Troubleshooting(3)
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NAME

6       DBIx::Class::Manual::Troubleshooting - Got a problem? Shoot it.
7
8   "Can't locate storage blabla"
9       You're trying to make a query on a non-connected schema. Make sure you
10       got the current resultset from $schema->resultset('Artist') on a schema
11       object you got back from connect().
12
13   Tracing SQL
14       The "DBIC_TRACE" environment variable controls SQL tracing, so to see
15       what is happening try
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17         export DBIC_TRACE=1
18
19       Alternatively use the "storage->debug" class method:-
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21         $schema->storage->debug(1);
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23       To send the output somewhere else set debugfh:-
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25         $schema->storage->debugfh(IO::File->new('/tmp/trace.out', 'w'));
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27       Alternatively you can do this with the environment variable, too:-
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29         export DBIC_TRACE="1=/tmp/trace.out"
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31   Can't locate method result_source_instance
32       For some reason the table class in question didn't load fully, so the
33       ResultSource object for it hasn't been created. Debug this class in
34       isolation, then try loading the full schema again.
35
36   Can't get last insert ID under Postgres with serial primary keys
37       Older DBI and DBD::Pg versions do not handle "last_insert_id"
38       correctly, causing code that uses auto-incrementing primary key columns
39       to fail with a message such as:
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41         Can't get last insert id at /.../DBIx/Class/Row.pm line 95
42
43       In particular the RHEL 4 and FC3 Linux distributions both ship with
44       combinations of DBI and DBD::Pg modules that do not work correctly.
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46       DBI version 1.50 and DBD::Pg 1.43 are known to work.
47
48   Can't locate object method "source_name" via package
49       There's likely a syntax error in the table class referred to elsewhere
50       in this error message.  In particular make sure that the package
51       declaration is correct. For example, for a schema " MySchema " you need
52       to specify a fully qualified namespace: " package MySchema::MyTable; ".
53
54   syntax error at or near "<something>" ...
55       This can happen if you have a relation whose name is a word reserved by
56       your database, e.g. "user":
57
58         package My::Schema::User;
59         ...
60         __PACKAGE__->table('users');
61         __PACKAGE__->add_columns(qw/ id name /);
62         __PACKAGE__->set_primary_key('id');
63         ...
64         1;
65
66         package My::Schema::ACL;
67         ...
68         __PACKAGE__->table('acl');
69         __PACKAGE__->add_columns(qw/ user_id /);
70         __PACKAGE__->belongs_to( 'user' => 'My::Schema::User', 'user_id' );
71         ...
72         1;
73
74         $schema->resultset('ACL')->search(
75           {},
76           {
77             join => [qw/ user /],
78             '+select' => [ 'user.name' ]
79           }
80         );
81
82       The SQL generated would resemble something like:
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84         SELECT me.user_id, user.name FROM acl me
85         JOIN users user ON me.user_id = user.id
86
87       If, as is likely, your database treats "user" as a reserved word, you'd
88       end up with the following errors:
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90       1) syntax error at or near "." - due to "user.name" in the SELECT
91       clause
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93       2) syntax error at or near "user" - due to "user" in the JOIN clause
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95       The solution is to enable quoting - see "Setting quoting for the
96       generated SQL" in DBIx::Class::Manual::Cookbook for details.
97
98   column "foo DESC" does not exist ...
99       This can happen if you are still using the obsolete order hack, and
100       also happen to turn on SQL-quoting.
101
102         $rs->search( {}, { order_by => [ 'name DESC' ] } );
103
104       The above should be written as:
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106         $rs->search( {}, { order_by => { -desc => 'name' } } );
107
108       For more ways to express order clauses refer to "ORDER BY CLAUSES" in
109       SQL::Abstract::Classic
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111   Perl Performance Issues on Red Hat Systems
112       There is a problem with slow performance of certain DBIx::Class
113       operations using the system perl on some Fedora and Red Hat Enterprise
114       Linux system (as well as their derivative distributions such as Centos,
115       White Box and Scientific Linux).
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117       Distributions affected include Fedora 5 through to Fedora 8 and RHEL5
118       up to and including RHEL5 Update 2. Fedora 9 (which uses perl 5.10) has
119       never been affected - this is purely a perl 5.8.8 issue.
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121       As of September 2008 the following packages are known to be fixed and
122       so free of this performance issue (this means all Fedora and RHEL5
123       systems with full current updates will not be subject to this
124       problem):-
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126         Fedora 8     - perl-5.8.8-41.fc8
127         RHEL5        - perl-5.8.8-15.el5_2.1
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129       This issue is due to perl doing an exhaustive search of blessed objects
130       under certain circumstances.  The problem shows up as performance
131       degradation exponential to the number of DBIx::Class result objects in
132       memory, so can be unnoticeable with certain data sets, but with huge
133       performance impacts on other datasets.
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135       A pair of tests for susceptibility to the issue and performance effects
136       of the bless/overload problem can be found in the DBIx::Class test
137       suite, in the "t/99rh_perl_perf_bug.t" file.
138
139       Further information on this issue can be found in
140       <https://bugzilla.redhat.com/show_bug.cgi?id=379791>,
141       <https://bugzilla.redhat.com/show_bug.cgi?id=460308> and
142       <http://rhn.redhat.com/errata/RHBA-2008-0876.html>
143
144   Excessive Memory Allocation with TEXT/BLOB/etc. Columns and Large
145       LongReadLen
146       It has been observed, using DBD::ODBC, that creating a DBIx::Class::Row
147       object which includes a column of data type TEXT/BLOB/etc. will
148       allocate LongReadLen bytes.  This allocation does not leak, but if
149       LongReadLen is large in size, and many such result objects are created,
150       e.g. as the output of a ResultSet query, the memory footprint of the
151       Perl interpreter can grow very large.
152
153       The solution is to use the smallest practical value for LongReadLen.
154

FURTHER QUESTIONS?

156       Check the list of additional DBIC resources.
157
159       This module is free software copyright by the DBIx::Class (DBIC)
160       authors. You can redistribute it and/or modify it under the same terms
161       as the DBIx::Class library.
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165perl v5.34.0                      2021-0D7B-I2x2::Class::Manual::Troubleshooting(3)
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