Commit | Line | Data |
2156bbdd |
1 | package DBIx::Class::Storage::DBI::Replicated; |
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2 | |
c96bf2bc |
3 | use warnings; |
4 | use strict; |
5 | |
ecb65397 |
6 | BEGIN { |
c96bf2bc |
7 | require DBIx::Class::Optional::Dependencies; |
8 | if ( my $missing = DBIx::Class::Optional::Dependencies->req_missing_for('replicated') ) { |
9 | die "The following modules are required for Replicated storage support: $missing\n"; |
10 | } |
ecb65397 |
11 | } |
12 | |
b2e4d522 |
13 | use Moose; |
26ab719a |
14 | use DBIx::Class::Storage::DBI; |
2bf79155 |
15 | use DBIx::Class::Storage::DBI::Replicated::Pool; |
26ab719a |
16 | use DBIx::Class::Storage::DBI::Replicated::Balancer; |
6a151f58 |
17 | use DBIx::Class::Storage::DBI::Replicated::Types qw/BalancerClassNamePart DBICSchema DBICStorageDBI/; |
41916570 |
18 | use MooseX::Types::Moose qw/ClassName HashRef Object/; |
b2e4d522 |
19 | use Scalar::Util 'reftype'; |
e666c5fd |
20 | use Hash::Merge; |
7da56142 |
21 | use List::Util qw/min max reduce/; |
1abccf54 |
22 | use Context::Preserve 'preserve_context'; |
ed7ab0f4 |
23 | use Try::Tiny; |
ddcc02d1 |
24 | use DBIx::Class::_Util 'dbic_internal_try'; |
9901aad7 |
25 | |
26 | use namespace::clean -except => 'meta'; |
2bf79155 |
27 | |
28 | =head1 NAME |
29 | |
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30 | DBIx::Class::Storage::DBI::Replicated - BETA Replicated database support |
2bf79155 |
31 | |
32 | =head1 SYNOPSIS |
33 | |
34 | The Following example shows how to change an existing $schema to a replicated |
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35 | storage type, add some replicated (read-only) databases, and perform reporting |
955a6df6 |
36 | tasks. |
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37 | |
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38 | You should set the 'storage_type attribute to a replicated type. You should |
d4daee7b |
39 | also define your arguments, such as which balancer you want and any arguments |
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40 | that the Pool object should get. |
41 | |
ce854fd3 |
42 | my $schema = Schema::Class->clone; |
592fa86f |
43 | $schema->storage_type(['::DBI::Replicated', { balancer_type => '::Random' }]); |
ce854fd3 |
44 | $schema->connection(...); |
d4daee7b |
45 | |
fd323bf1 |
46 | Next, you need to add in the Replicants. Basically this is an array of |
3da4f736 |
47 | arrayrefs, where each arrayref is database connect information. Think of these |
48 | arguments as what you'd pass to the 'normal' $schema->connect method. |
d4daee7b |
49 | |
64cdad22 |
50 | $schema->storage->connect_replicants( |
51 | [$dsn1, $user, $pass, \%opts], |
52 | [$dsn2, $user, $pass, \%opts], |
53 | [$dsn3, $user, $pass, \%opts], |
54 | ); |
d4daee7b |
55 | |
3da4f736 |
56 | Now, just use the $schema as you normally would. Automatically all reads will |
57 | be delegated to the replicants, while writes to the master. |
58 | |
7e38d850 |
59 | $schema->resultset('Source')->search({name=>'etc'}); |
d4daee7b |
60 | |
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61 | You can force a given query to use a particular storage using the search |
62 | attribute 'force_pool'. For example: |
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63 | |
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64 | my $rs = $schema->resultset('Source')->search(undef, {force_pool=>'master'}); |
3da4f736 |
65 | |
d7c37d66 |
66 | Now $rs will force everything (both reads and writes) to use whatever was setup |
fd323bf1 |
67 | as the master storage. 'master' is hardcoded to always point to the Master, |
3da4f736 |
68 | but you can also use any Replicant name. Please see: |
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69 | L<DBIx::Class::Storage::DBI::Replicated::Pool> and the replicants attribute for more. |
3da4f736 |
70 | |
71 | Also see transactions and L</execute_reliably> for alternative ways to |
72 | force read traffic to the master. In general, you should wrap your statements |
73 | in a transaction when you are reading and writing to the same tables at the |
74 | same time, since your replicants will often lag a bit behind the master. |
212cc5c2 |
75 | |
d7c37d66 |
76 | If you have a multi-statement read only transaction you can force it to select |
77 | a random server in the pool by: |
78 | |
79 | my $rs = $schema->resultset('Source')->search( undef, |
80 | { force_pool => $db->storage->read_handler->next_storage } |
81 | ); |
d4daee7b |
82 | |
2bf79155 |
83 | =head1 DESCRIPTION |
84 | |
7e38d850 |
85 | Warning: This class is marked BETA. This has been running a production |
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86 | website using MySQL native replication as its backend and we have some decent |
7e38d850 |
87 | test coverage but the code hasn't yet been stressed by a variety of databases. |
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88 | Individual DBs may have quirks we are not aware of. Please use this in first |
7e38d850 |
89 | development and pass along your experiences/bug fixes. |
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90 | |
91 | This class implements replicated data store for DBI. Currently you can define |
92 | one master and numerous slave database connections. All write-type queries |
93 | (INSERT, UPDATE, DELETE and even LAST_INSERT_ID) are routed to master |
94 | database, all read-type queries (SELECTs) go to the slave database. |
95 | |
96 | Basically, any method request that L<DBIx::Class::Storage::DBI> would normally |
bca099a3 |
97 | handle gets delegated to one of the two attributes: L</read_handler> or to |
98 | L</write_handler>. Additionally, some methods need to be distributed |
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99 | to all existing storages. This way our storage class is a drop in replacement |
100 | for L<DBIx::Class::Storage::DBI>. |
101 | |
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102 | Read traffic is spread across the replicants (slaves) occurring to a user |
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103 | selected algorithm. The default algorithm is random weighted. |
104 | |
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105 | =head1 NOTES |
106 | |
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107 | The consistency between master and replicants is database specific. The Pool |
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108 | gives you a method to validate its replicants, removing and replacing them |
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109 | when they fail/pass predefined criteria. Please make careful use of the ways |
ecb65397 |
110 | to force a query to run against Master when needed. |
111 | |
112 | =head1 REQUIREMENTS |
113 | |
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114 | Replicated Storage has additional requirements not currently part of |
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115 | L<DBIx::Class>. See L<DBIx::Class::Optional::Dependencies> for more details. |
2bf79155 |
116 | |
117 | =head1 ATTRIBUTES |
118 | |
119 | This class defines the following attributes. |
120 | |
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121 | =head2 schema |
122 | |
123 | The underlying L<DBIx::Class::Schema> object this storage is attaching |
124 | |
125 | =cut |
126 | |
127 | has 'schema' => ( |
128 | is=>'rw', |
6a151f58 |
129 | isa=>DBICSchema, |
2ce6e9a6 |
130 | weak_ref=>1, |
131 | required=>1, |
132 | ); |
133 | |
26ab719a |
134 | =head2 pool_type |
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135 | |
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136 | Contains the classname which will instantiate the L</pool> object. Defaults |
26ab719a |
137 | to: L<DBIx::Class::Storage::DBI::Replicated::Pool>. |
2bf79155 |
138 | |
139 | =cut |
140 | |
26ab719a |
141 | has 'pool_type' => ( |
dcdf7b2c |
142 | is=>'rw', |
41916570 |
143 | isa=>ClassName, |
2ce6e9a6 |
144 | default=>'DBIx::Class::Storage::DBI::Replicated::Pool', |
64cdad22 |
145 | handles=>{ |
146 | 'create_pool' => 'new', |
147 | }, |
2bf79155 |
148 | ); |
149 | |
f068a139 |
150 | =head2 pool_args |
151 | |
152 | Contains a hashref of initialized information to pass to the Balancer object. |
212cc5c2 |
153 | See L<DBIx::Class::Storage::DBI::Replicated::Pool> for available arguments. |
f068a139 |
154 | |
155 | =cut |
156 | |
157 | has 'pool_args' => ( |
dcdf7b2c |
158 | is=>'rw', |
41916570 |
159 | isa=>HashRef, |
64cdad22 |
160 | lazy=>1, |
64cdad22 |
161 | default=>sub { {} }, |
f068a139 |
162 | ); |
163 | |
164 | |
26ab719a |
165 | =head2 balancer_type |
2bf79155 |
166 | |
167 | The replication pool requires a balance class to provider the methods for |
168 | choose how to spread the query load across each replicant in the pool. |
169 | |
170 | =cut |
171 | |
26ab719a |
172 | has 'balancer_type' => ( |
dcdf7b2c |
173 | is=>'rw', |
9901aad7 |
174 | isa=>BalancerClassNamePart, |
2ce6e9a6 |
175 | coerce=>1, |
176 | required=>1, |
177 | default=> 'DBIx::Class::Storage::DBI::Replicated::Balancer::First', |
64cdad22 |
178 | handles=>{ |
179 | 'create_balancer' => 'new', |
180 | }, |
2bf79155 |
181 | ); |
182 | |
17b05c13 |
183 | =head2 balancer_args |
184 | |
185 | Contains a hashref of initialized information to pass to the Balancer object. |
212cc5c2 |
186 | See L<DBIx::Class::Storage::DBI::Replicated::Balancer> for available arguments. |
17b05c13 |
187 | |
188 | =cut |
189 | |
190 | has 'balancer_args' => ( |
dcdf7b2c |
191 | is=>'rw', |
41916570 |
192 | isa=>HashRef, |
64cdad22 |
193 | lazy=>1, |
194 | required=>1, |
195 | default=>sub { {} }, |
17b05c13 |
196 | ); |
197 | |
26ab719a |
198 | =head2 pool |
2bf79155 |
199 | |
370f78d4 |
200 | Is a L<DBIx::Class::Storage::DBI::Replicated::Pool> or derived class. This is a |
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201 | container class for one or more replicated databases. |
2bf79155 |
202 | |
203 | =cut |
204 | |
26ab719a |
205 | has 'pool' => ( |
64cdad22 |
206 | is=>'ro', |
207 | isa=>'DBIx::Class::Storage::DBI::Replicated::Pool', |
208 | lazy_build=>1, |
209 | handles=>[qw/ |
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210 | connect_replicants |
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211 | replicants |
212 | has_replicants |
213 | /], |
2bf79155 |
214 | ); |
215 | |
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216 | =head2 balancer |
2bf79155 |
217 | |
370f78d4 |
218 | Is a L<DBIx::Class::Storage::DBI::Replicated::Balancer> or derived class. This |
219 | is a class that takes a pool (L<DBIx::Class::Storage::DBI::Replicated::Pool>) |
2bf79155 |
220 | |
26ab719a |
221 | =cut |
2bf79155 |
222 | |
26ab719a |
223 | has 'balancer' => ( |
dcdf7b2c |
224 | is=>'rw', |
64cdad22 |
225 | isa=>'DBIx::Class::Storage::DBI::Replicated::Balancer', |
226 | lazy_build=>1, |
227 | handles=>[qw/auto_validate_every/], |
26ab719a |
228 | ); |
2bf79155 |
229 | |
cb6ec758 |
230 | =head2 master |
231 | |
232 | The master defines the canonical state for a pool of connected databases. All |
233 | the replicants are expected to match this databases state. Thus, in a classic |
234 | Master / Slaves distributed system, all the slaves are expected to replicate |
235 | the Master's state as quick as possible. This is the only database in the |
236 | pool of databases that is allowed to handle write traffic. |
237 | |
238 | =cut |
239 | |
240 | has 'master' => ( |
64cdad22 |
241 | is=> 'ro', |
6a151f58 |
242 | isa=>DBICStorageDBI, |
64cdad22 |
243 | lazy_build=>1, |
cb6ec758 |
244 | ); |
245 | |
cb6ec758 |
246 | =head1 ATTRIBUTES IMPLEMENTING THE DBIx::Storage::DBI INTERFACE |
247 | |
fd323bf1 |
248 | The following methods are delegated all the methods required for the |
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249 | L<DBIx::Class::Storage::DBI> interface. |
250 | |
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251 | =cut |
252 | |
4bea1fe7 |
253 | my $method_dispatch = { |
254 | writer => [qw/ |
64cdad22 |
255 | on_connect_do |
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256 | on_disconnect_do |
3244fdcc |
257 | on_connect_call |
258 | on_disconnect_call |
64cdad22 |
259 | connect_info |
3244fdcc |
260 | _connect_info |
64cdad22 |
261 | throw_exception |
262 | sql_maker |
263 | sqlt_type |
264 | create_ddl_dir |
265 | deployment_statements |
266 | datetime_parser |
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267 | datetime_parser_type |
268 | build_datetime_parser |
64cdad22 |
269 | last_insert_id |
270 | insert |
64cdad22 |
271 | update |
272 | delete |
273 | dbh |
2ce6e9a6 |
274 | txn_begin |
64cdad22 |
275 | txn_do |
276 | txn_commit |
277 | txn_rollback |
2ce6e9a6 |
278 | txn_scope_guard |
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279 | _exec_txn_rollback |
280 | _exec_txn_begin |
281 | _exec_txn_commit |
64cdad22 |
282 | deploy |
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283 | with_deferred_fk_checks |
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284 | dbh_do |
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285 | _prep_for_execute |
6f7344b8 |
286 | is_datatype_numeric |
287 | _count_select |
6f7344b8 |
288 | svp_rollback |
289 | svp_begin |
290 | svp_release |
e398f77e |
291 | relname_to_table_alias |
3244fdcc |
292 | _dbh_last_insert_id |
3244fdcc |
293 | _default_dbi_connect_attributes |
294 | _dbi_connect_info |
b9ca4ff1 |
295 | _dbic_connect_attributes |
3244fdcc |
296 | auto_savepoint |
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297 | _query_start |
3244fdcc |
298 | _query_end |
0e773352 |
299 | _format_for_trace |
300 | _dbi_attrs_for_bind |
3244fdcc |
301 | bind_attribute_by_data_type |
302 | transaction_depth |
303 | _dbh |
304 | _select_args |
52cef7e3 |
305 | _dbh_execute_for_fetch |
3244fdcc |
306 | _sql_maker |
3244fdcc |
307 | _dbh_execute_inserts_with_no_binds |
308 | _select_args_to_query |
5e782048 |
309 | _gen_sql_bind |
3244fdcc |
310 | _svp_generate_name |
3244fdcc |
311 | _normalize_connect_info |
312 | _parse_connect_do |
3244fdcc |
313 | savepoints |
3244fdcc |
314 | _sql_maker_opts |
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315 | _use_multicolumn_in |
3244fdcc |
316 | _conn_pid |
3244fdcc |
317 | _dbh_autocommit |
318 | _native_data_type |
319 | _get_dbh |
320 | sql_maker_class |
2a6dda4b |
321 | insert_bulk |
322 | _insert_bulk |
3244fdcc |
323 | _execute |
324 | _do_query |
3244fdcc |
325 | _dbh_execute |
5b4f3fd0 |
326 | /, Class::MOP::Class->initialize('DBIx::Class::Storage::DBIHacks')->get_method_list ], |
4bea1fe7 |
327 | reader => [qw/ |
328 | select |
329 | select_single |
330 | columns_info_for |
331 | _dbh_columns_info_for |
332 | _select |
333 | /], |
334 | unimplemented => [qw/ |
335 | _arm_global_destructor |
336 | _verify_pid |
84efb6d7 |
337 | __delicate_rollback |
4bea1fe7 |
338 | |
339 | get_use_dbms_capability |
340 | set_use_dbms_capability |
341 | get_dbms_capability |
342 | set_dbms_capability |
343 | _dbh_details |
344 | _dbh_get_info |
b0c42bbc |
345 | _get_rdbms_name |
4bea1fe7 |
346 | |
75d3bdb2 |
347 | _determine_connector_driver |
37b5ab51 |
348 | _extract_driver_from_connect_info |
75d3bdb2 |
349 | _describe_connection |
350 | _warn_undetermined_driver |
351 | |
4bea1fe7 |
352 | sql_limit_dialect |
353 | sql_quote_char |
354 | sql_name_sep |
355 | |
4bea1fe7 |
356 | _prefetch_autovalues |
fabbd5cc |
357 | _perform_autoinc_retrieval |
358 | _autoinc_supplied_for_op |
4bea1fe7 |
359 | |
eec07bca |
360 | _resolve_bindattrs |
361 | |
4bea1fe7 |
362 | _max_column_bytesize |
363 | _is_lob_type |
364 | _is_binary_lob_type |
5efba7fc |
365 | _is_binary_type |
4bea1fe7 |
366 | _is_text_lob_type |
402ac1c9 |
367 | |
9930caaf |
368 | _prepare_sth |
369 | _bind_sth_params |
4bea1fe7 |
370 | /,( |
371 | # the capability framework |
372 | # not sure if CMOP->initialize does evil things to DBIC::S::DBI, fix if a problem |
373 | grep |
7d6c28b7 |
374 | { $_ =~ /^ _ (?: use | supports | determine_supports ) _ /x and $_ ne '_use_multicolumn_in' } |
4bea1fe7 |
375 | ( Class::MOP::Class->initialize('DBIx::Class::Storage::DBI')->get_all_method_names ) |
376 | )], |
377 | }; |
378 | |
08a8d8f1 |
379 | # this only happens during DBIC-internal testing |
380 | if ( $INC{"t/lib/ANFANG.pm"} ) { |
4bea1fe7 |
381 | |
382 | my $seen; |
383 | for my $type (keys %$method_dispatch) { |
384 | for (@{$method_dispatch->{$type}}) { |
385 | push @{$seen->{$_}}, $type; |
386 | } |
387 | } |
cb6ec758 |
388 | |
4bea1fe7 |
389 | if (my @dupes = grep { @{$seen->{$_}} > 1 } keys %$seen) { |
390 | die(join "\n", '', |
391 | 'The following methods show up multiple times in ::Storage::DBI::Replicated handlers:', |
392 | (map { "$_: " . (join ', ', @{$seen->{$_}}) } sort @dupes), |
393 | '', |
394 | ); |
395 | } |
bbdda281 |
396 | |
4bea1fe7 |
397 | if (my @cant = grep { ! DBIx::Class::Storage::DBI->can($_) } keys %$seen) { |
398 | die(join "\n", '', |
399 | '::Storage::DBI::Replicated specifies handling of the following *NON EXISTING* ::Storage::DBI methods:', |
400 | @cant, |
401 | '', |
402 | ); |
403 | } |
404 | } |
bbdda281 |
405 | |
4bea1fe7 |
406 | for my $method (@{$method_dispatch->{unimplemented}}) { |
407 | __PACKAGE__->meta->add_method($method, sub { |
70c28808 |
408 | my $self = shift; |
e705f529 |
409 | $self->throw_exception("$method() must not be called on ".(blessed $self).' objects'); |
4bea1fe7 |
410 | }); |
411 | } |
31a8aaaf |
412 | |
4bea1fe7 |
413 | =head2 read_handler |
584ea6e4 |
414 | |
5529838f |
415 | Defines an object that implements the read side of L<DBIx::Class::Storage::DBI>. |
584ea6e4 |
416 | |
4bea1fe7 |
417 | =cut |
418 | |
419 | has 'read_handler' => ( |
420 | is=>'rw', |
421 | isa=>Object, |
422 | lazy_build=>1, |
423 | handles=>$method_dispatch->{reader}, |
e471ab87 |
424 | ); |
425 | |
4bea1fe7 |
426 | =head2 write_handler |
427 | |
5529838f |
428 | Defines an object that implements the write side of L<DBIx::Class::Storage::DBI>, |
4bea1fe7 |
429 | as well as methods that don't write or read that can be called on only one |
430 | storage, methods that return a C<$dbh>, and any methods that don't make sense to |
431 | run on a replicant. |
432 | |
433 | =cut |
434 | |
435 | has 'write_handler' => ( |
436 | is=>'ro', |
437 | isa=>Object, |
438 | lazy_build=>1, |
439 | handles=>$method_dispatch->{writer}, |
7f4433eb |
440 | ); |
441 | |
4bea1fe7 |
442 | |
6d766626 |
443 | |
b2e4d522 |
444 | has _master_connect_info_opts => |
445 | (is => 'rw', isa => HashRef, default => sub { {} }); |
446 | |
447 | =head2 around: connect_info |
448 | |
48580715 |
449 | Preserves master's C<connect_info> options (for merging with replicants.) |
450 | Also sets any Replicated-related options from connect_info, such as |
dcdf7b2c |
451 | C<pool_type>, C<pool_args>, C<balancer_type> and C<balancer_args>. |
b2e4d522 |
452 | |
453 | =cut |
454 | |
455 | around connect_info => sub { |
456 | my ($next, $self, $info, @extra) = @_; |
457 | |
1fccee7b |
458 | $self->throw_exception( |
459 | 'connect_info can not be retrieved from a replicated storage - ' |
460 | . 'accessor must be called on a specific pool instance' |
461 | ) unless defined $info; |
462 | |
282a9a4f |
463 | my $merge = Hash::Merge->new('LEFT_PRECEDENT'); |
e666c5fd |
464 | |
b2e4d522 |
465 | my %opts; |
466 | for my $arg (@$info) { |
467 | next unless (reftype($arg)||'') eq 'HASH'; |
e666c5fd |
468 | %opts = %{ $merge->merge($arg, \%opts) }; |
b2e4d522 |
469 | } |
b2e4d522 |
470 | delete $opts{dsn}; |
471 | |
dcdf7b2c |
472 | if (@opts{qw/pool_type pool_args/}) { |
473 | $self->pool_type(delete $opts{pool_type}) |
474 | if $opts{pool_type}; |
475 | |
b88b85e7 |
476 | $self->pool_args( |
e666c5fd |
477 | $merge->merge((delete $opts{pool_args} || {}), $self->pool_args) |
b88b85e7 |
478 | ); |
dcdf7b2c |
479 | |
64ae1667 |
480 | ## Since we possibly changed the pool_args, we need to clear the current |
481 | ## pool object so that next time it is used it will be rebuilt. |
482 | $self->clear_pool; |
dcdf7b2c |
483 | } |
484 | |
485 | if (@opts{qw/balancer_type balancer_args/}) { |
486 | $self->balancer_type(delete $opts{balancer_type}) |
487 | if $opts{balancer_type}; |
488 | |
b88b85e7 |
489 | $self->balancer_args( |
e666c5fd |
490 | $merge->merge((delete $opts{balancer_args} || {}), $self->balancer_args) |
b88b85e7 |
491 | ); |
dcdf7b2c |
492 | |
67c43863 |
493 | $self->balancer($self->_build_balancer) |
6f7344b8 |
494 | if $self->balancer; |
dcdf7b2c |
495 | } |
496 | |
b2e4d522 |
497 | $self->_master_connect_info_opts(\%opts); |
498 | |
1abccf54 |
499 | return preserve_context { |
500 | $self->$next($info, @extra); |
501 | } after => sub { |
502 | # Make sure master is blessed into the correct class and apply role to it. |
503 | my $master = $self->master; |
504 | $master->_determine_driver; |
505 | Moose::Meta::Class->initialize(ref $master); |
cea43436 |
506 | |
1abccf54 |
507 | DBIx::Class::Storage::DBI::Replicated::WithDSN->meta->apply($master); |
0ce2d0d5 |
508 | |
1abccf54 |
509 | # link pool back to master |
510 | $self->pool->master($master); |
511 | }; |
b2e4d522 |
512 | }; |
513 | |
26ab719a |
514 | =head1 METHODS |
2bf79155 |
515 | |
26ab719a |
516 | This class defines the following methods. |
2bf79155 |
517 | |
c354902c |
518 | =head2 BUILDARGS |
2bf79155 |
519 | |
faaba25f |
520 | L<DBIx::Class::Schema> when instantiating its storage passed itself as the |
2ce6e9a6 |
521 | first argument. So we need to massage the arguments a bit so that all the |
522 | bits get put into the correct places. |
2bf79155 |
523 | |
524 | =cut |
525 | |
c354902c |
526 | sub BUILDARGS { |
fd323bf1 |
527 | my ($class, $schema, $storage_type_args, @args) = @_; |
d4daee7b |
528 | |
c354902c |
529 | return { |
6f7344b8 |
530 | schema=>$schema, |
531 | %$storage_type_args, |
532 | @args |
c354902c |
533 | } |
534 | } |
2bf79155 |
535 | |
cb6ec758 |
536 | =head2 _build_master |
2bf79155 |
537 | |
cb6ec758 |
538 | Lazy builder for the L</master> attribute. |
2bf79155 |
539 | |
540 | =cut |
541 | |
cb6ec758 |
542 | sub _build_master { |
2ce6e9a6 |
543 | my $self = shift @_; |
ee356d00 |
544 | my $master = DBIx::Class::Storage::DBI->new($self->schema); |
ee356d00 |
545 | $master |
106d5f3b |
546 | } |
547 | |
26ab719a |
548 | =head2 _build_pool |
2bf79155 |
549 | |
26ab719a |
550 | Lazy builder for the L</pool> attribute. |
2bf79155 |
551 | |
552 | =cut |
553 | |
26ab719a |
554 | sub _build_pool { |
64cdad22 |
555 | my $self = shift @_; |
556 | $self->create_pool(%{$self->pool_args}); |
2bf79155 |
557 | } |
558 | |
26ab719a |
559 | =head2 _build_balancer |
2bf79155 |
560 | |
cb6ec758 |
561 | Lazy builder for the L</balancer> attribute. This takes a Pool object so that |
562 | the balancer knows which pool it's balancing. |
2bf79155 |
563 | |
564 | =cut |
565 | |
26ab719a |
566 | sub _build_balancer { |
64cdad22 |
567 | my $self = shift @_; |
568 | $self->create_balancer( |
6f7344b8 |
569 | pool=>$self->pool, |
64cdad22 |
570 | master=>$self->master, |
571 | %{$self->balancer_args}, |
572 | ); |
2bf79155 |
573 | } |
574 | |
cb6ec758 |
575 | =head2 _build_write_handler |
2bf79155 |
576 | |
cb6ec758 |
577 | Lazy builder for the L</write_handler> attribute. The default is to set this to |
578 | the L</master>. |
50336325 |
579 | |
580 | =cut |
581 | |
cb6ec758 |
582 | sub _build_write_handler { |
64cdad22 |
583 | return shift->master; |
cb6ec758 |
584 | } |
50336325 |
585 | |
cb6ec758 |
586 | =head2 _build_read_handler |
2bf79155 |
587 | |
cb6ec758 |
588 | Lazy builder for the L</read_handler> attribute. The default is to set this to |
589 | the L</balancer>. |
2bf79155 |
590 | |
591 | =cut |
592 | |
cb6ec758 |
593 | sub _build_read_handler { |
64cdad22 |
594 | return shift->balancer; |
cb6ec758 |
595 | } |
50336325 |
596 | |
cb6ec758 |
597 | =head2 around: connect_replicants |
2bf79155 |
598 | |
cb6ec758 |
599 | All calls to connect_replicants needs to have an existing $schema tacked onto |
5529838f |
600 | top of the args, since L<DBIx::Class::Storage::DBI> needs it, and any |
601 | L<connect_info|DBIx::Class::Storage::DBI/connect_info> |
b2e4d522 |
602 | options merged with the master, with replicant opts having higher priority. |
955a6df6 |
603 | |
cb6ec758 |
604 | =cut |
955a6df6 |
605 | |
b2e4d522 |
606 | around connect_replicants => sub { |
607 | my ($next, $self, @args) = @_; |
608 | |
609 | for my $r (@args) { |
610 | $r = [ $r ] unless reftype $r eq 'ARRAY'; |
611 | |
1a58752c |
612 | $self->throw_exception('coderef replicant connect_info not supported') |
b2e4d522 |
613 | if ref $r->[0] && reftype $r->[0] eq 'CODE'; |
614 | |
615 | # any connect_info options? |
616 | my $i = 0; |
617 | $i++ while $i < @$r && (reftype($r->[$i])||'') ne 'HASH'; |
618 | |
6f7344b8 |
619 | # make one if none |
b2e4d522 |
620 | $r->[$i] = {} unless $r->[$i]; |
621 | |
622 | # merge if two hashes |
b88b85e7 |
623 | my @hashes = @$r[$i .. $#{$r}]; |
624 | |
1a58752c |
625 | $self->throw_exception('invalid connect_info options') |
b88b85e7 |
626 | if (grep { reftype($_) eq 'HASH' } @hashes) != @hashes; |
627 | |
1a58752c |
628 | $self->throw_exception('too many hashrefs in connect_info') |
b88b85e7 |
629 | if @hashes > 2; |
630 | |
282a9a4f |
631 | my $merge = Hash::Merge->new('LEFT_PRECEDENT'); |
e666c5fd |
632 | my %opts = %{ $merge->merge(reverse @hashes) }; |
b88b85e7 |
633 | |
634 | # delete them |
b2e4d522 |
635 | splice @$r, $i+1, ($#{$r} - $i), (); |
636 | |
0bd8e058 |
637 | # make sure master/replicants opts don't clash |
638 | my %master_opts = %{ $self->_master_connect_info_opts }; |
639 | if (exists $opts{dbh_maker}) { |
640 | delete @master_opts{qw/dsn user password/}; |
641 | } |
642 | delete $master_opts{dbh_maker}; |
643 | |
b2e4d522 |
644 | # merge with master |
e666c5fd |
645 | %opts = %{ $merge->merge(\%opts, \%master_opts) }; |
b2e4d522 |
646 | |
647 | # update |
648 | $r->[$i] = \%opts; |
649 | } |
650 | |
651 | $self->$next($self->schema, @args); |
955a6df6 |
652 | }; |
2bf79155 |
653 | |
2bf79155 |
654 | =head2 all_storages |
655 | |
4a0eed52 |
656 | Returns an array of all the connected storage backends. The first element |
657 | in the returned array is the master, and the rest are each of the |
2bf79155 |
658 | replicants. |
659 | |
660 | =cut |
661 | |
662 | sub all_storages { |
64cdad22 |
663 | my $self = shift @_; |
664 | return grep {defined $_ && blessed $_} ( |
665 | $self->master, |
6412a592 |
666 | values %{ $self->replicants }, |
64cdad22 |
667 | ); |
2bf79155 |
668 | } |
669 | |
c4d3fae2 |
670 | =head2 execute_reliably ($coderef, ?@args) |
671 | |
672 | Given a coderef, saves the current state of the L</read_handler>, forces it to |
48580715 |
673 | use reliable storage (e.g. sets it to the master), executes a coderef and then |
c4d3fae2 |
674 | restores the original state. |
675 | |
676 | Example: |
677 | |
64cdad22 |
678 | my $reliably = sub { |
679 | my $name = shift @_; |
680 | $schema->resultset('User')->create({name=>$name}); |
fd323bf1 |
681 | my $user_rs = $schema->resultset('User')->find({name=>$name}); |
64cdad22 |
682 | return $user_rs; |
683 | }; |
c4d3fae2 |
684 | |
64cdad22 |
685 | my $user_rs = $schema->storage->execute_reliably($reliably, 'John'); |
c4d3fae2 |
686 | |
687 | Use this when you must be certain of your database state, such as when you just |
688 | inserted something and need to get a resultset including it, etc. |
689 | |
690 | =cut |
691 | |
692 | sub execute_reliably { |
1abccf54 |
693 | my $self = shift; |
694 | my $coderef = shift; |
d4daee7b |
695 | |
67cbc0a8 |
696 | $self->throw_exception('Second argument must be a coderef') |
697 | unless( ref $coderef eq 'CODE'); |
d4daee7b |
698 | |
1abccf54 |
699 | ## replace the current read handler for the remainder of the scope |
700 | local $self->{read_handler} = $self->master; |
d4daee7b |
701 | |
67cbc0a8 |
702 | &$coderef; |
c4d3fae2 |
703 | } |
704 | |
cb6ec758 |
705 | =head2 set_reliable_storage |
706 | |
707 | Sets the current $schema to be 'reliable', that is all queries, both read and |
708 | write are sent to the master |
d4daee7b |
709 | |
cb6ec758 |
710 | =cut |
711 | |
712 | sub set_reliable_storage { |
64cdad22 |
713 | my $self = shift @_; |
714 | my $schema = $self->schema; |
715 | my $write_handler = $self->schema->storage->write_handler; |
d4daee7b |
716 | |
64cdad22 |
717 | $schema->storage->read_handler($write_handler); |
cb6ec758 |
718 | } |
719 | |
720 | =head2 set_balanced_storage |
721 | |
722 | Sets the current $schema to be use the </balancer> for all reads, while all |
48580715 |
723 | writes are sent to the master only |
d4daee7b |
724 | |
cb6ec758 |
725 | =cut |
726 | |
727 | sub set_balanced_storage { |
64cdad22 |
728 | my $self = shift @_; |
729 | my $schema = $self->schema; |
bd5da369 |
730 | my $balanced_handler = $self->schema->storage->balancer; |
d4daee7b |
731 | |
bd5da369 |
732 | $schema->storage->read_handler($balanced_handler); |
cb6ec758 |
733 | } |
2bf79155 |
734 | |
735 | =head2 connected |
736 | |
737 | Check that the master and at least one of the replicants is connected. |
738 | |
739 | =cut |
740 | |
741 | sub connected { |
64cdad22 |
742 | my $self = shift @_; |
743 | return |
744 | $self->master->connected && |
745 | $self->pool->connected_replicants; |
2bf79155 |
746 | } |
747 | |
2bf79155 |
748 | =head2 ensure_connected |
749 | |
750 | Make sure all the storages are connected. |
751 | |
752 | =cut |
753 | |
754 | sub ensure_connected { |
64cdad22 |
755 | my $self = shift @_; |
756 | foreach my $source ($self->all_storages) { |
757 | $source->ensure_connected(@_); |
758 | } |
2bf79155 |
759 | } |
760 | |
2bf79155 |
761 | =head2 limit_dialect |
762 | |
763 | Set the limit_dialect for all existing storages |
764 | |
765 | =cut |
766 | |
767 | sub limit_dialect { |
64cdad22 |
768 | my $self = shift @_; |
769 | foreach my $source ($self->all_storages) { |
770 | $source->limit_dialect(@_); |
771 | } |
f3e9f010 |
772 | return $self->master->limit_dialect; |
2bf79155 |
773 | } |
774 | |
2bf79155 |
775 | =head2 quote_char |
776 | |
777 | Set the quote_char for all existing storages |
778 | |
779 | =cut |
780 | |
781 | sub quote_char { |
64cdad22 |
782 | my $self = shift @_; |
783 | foreach my $source ($self->all_storages) { |
784 | $source->quote_char(@_); |
785 | } |
3fbe08e3 |
786 | return $self->master->quote_char; |
2bf79155 |
787 | } |
788 | |
2bf79155 |
789 | =head2 name_sep |
790 | |
791 | Set the name_sep for all existing storages |
792 | |
793 | =cut |
794 | |
795 | sub name_sep { |
64cdad22 |
796 | my $self = shift @_; |
797 | foreach my $source ($self->all_storages) { |
798 | $source->name_sep(@_); |
799 | } |
3fbe08e3 |
800 | return $self->master->name_sep; |
2bf79155 |
801 | } |
802 | |
2bf79155 |
803 | =head2 set_schema |
804 | |
805 | Set the schema object for all existing storages |
806 | |
807 | =cut |
808 | |
809 | sub set_schema { |
64cdad22 |
810 | my $self = shift @_; |
811 | foreach my $source ($self->all_storages) { |
812 | $source->set_schema(@_); |
813 | } |
2bf79155 |
814 | } |
815 | |
2bf79155 |
816 | =head2 debug |
817 | |
818 | set a debug flag across all storages |
819 | |
820 | =cut |
821 | |
822 | sub debug { |
64cdad22 |
823 | my $self = shift @_; |
3fbe08e3 |
824 | if(@_) { |
825 | foreach my $source ($self->all_storages) { |
826 | $source->debug(@_); |
6f7344b8 |
827 | } |
64cdad22 |
828 | } |
3fbe08e3 |
829 | return $self->master->debug; |
2bf79155 |
830 | } |
831 | |
2bf79155 |
832 | =head2 debugobj |
833 | |
cea43436 |
834 | set a debug object |
2bf79155 |
835 | |
836 | =cut |
837 | |
838 | sub debugobj { |
64cdad22 |
839 | my $self = shift @_; |
cea43436 |
840 | return $self->master->debugobj(@_); |
2bf79155 |
841 | } |
842 | |
2bf79155 |
843 | =head2 debugfh |
844 | |
cea43436 |
845 | set a debugfh object |
2bf79155 |
846 | |
847 | =cut |
848 | |
849 | sub debugfh { |
64cdad22 |
850 | my $self = shift @_; |
cea43436 |
851 | return $self->master->debugfh(@_); |
2bf79155 |
852 | } |
853 | |
2bf79155 |
854 | =head2 debugcb |
855 | |
cea43436 |
856 | set a debug callback |
2bf79155 |
857 | |
858 | =cut |
859 | |
860 | sub debugcb { |
64cdad22 |
861 | my $self = shift @_; |
cea43436 |
862 | return $self->master->debugcb(@_); |
2bf79155 |
863 | } |
864 | |
2bf79155 |
865 | =head2 disconnect |
866 | |
867 | disconnect everything |
868 | |
869 | =cut |
870 | |
871 | sub disconnect { |
64cdad22 |
872 | my $self = shift @_; |
873 | foreach my $source ($self->all_storages) { |
874 | $source->disconnect(@_); |
875 | } |
2bf79155 |
876 | } |
877 | |
b2e4d522 |
878 | =head2 cursor_class |
879 | |
880 | set cursor class on all storages, or return master's |
881 | |
882 | =cut |
883 | |
884 | sub cursor_class { |
885 | my ($self, $cursor_class) = @_; |
886 | |
887 | if ($cursor_class) { |
888 | $_->cursor_class($cursor_class) for $self->all_storages; |
889 | } |
890 | $self->master->cursor_class; |
891 | } |
d4daee7b |
892 | |
3244fdcc |
893 | =head2 cursor |
894 | |
895 | set cursor class on all storages, or return master's, alias for L</cursor_class> |
896 | above. |
897 | |
898 | =cut |
899 | |
900 | sub cursor { |
901 | my ($self, $cursor_class) = @_; |
902 | |
903 | if ($cursor_class) { |
904 | $_->cursor($cursor_class) for $self->all_storages; |
905 | } |
906 | $self->master->cursor; |
907 | } |
908 | |
909 | =head2 unsafe |
910 | |
911 | sets the L<DBIx::Class::Storage::DBI/unsafe> option on all storages or returns |
912 | master's current setting |
913 | |
914 | =cut |
915 | |
916 | sub unsafe { |
917 | my $self = shift; |
918 | |
919 | if (@_) { |
920 | $_->unsafe(@_) for $self->all_storages; |
921 | } |
922 | |
923 | return $self->master->unsafe; |
924 | } |
925 | |
926 | =head2 disable_sth_caching |
927 | |
928 | sets the L<DBIx::Class::Storage::DBI/disable_sth_caching> option on all storages |
929 | or returns master's current setting |
930 | |
931 | =cut |
932 | |
933 | sub disable_sth_caching { |
934 | my $self = shift; |
935 | |
936 | if (@_) { |
937 | $_->disable_sth_caching(@_) for $self->all_storages; |
938 | } |
939 | |
940 | return $self->master->disable_sth_caching; |
941 | } |
942 | |
943 | =head2 lag_behind_master |
944 | |
945 | returns the highest Replicant L<DBIx::Class::Storage::DBI/lag_behind_master> |
946 | setting |
947 | |
948 | =cut |
949 | |
950 | sub lag_behind_master { |
951 | my $self = shift; |
952 | |
953 | return max map $_->lag_behind_master, $self->replicants; |
fd323bf1 |
954 | } |
3244fdcc |
955 | |
956 | =head2 is_replicating |
957 | |
958 | returns true if all replicants return true for |
959 | L<DBIx::Class::Storage::DBI/is_replicating> |
960 | |
961 | =cut |
962 | |
963 | sub is_replicating { |
964 | my $self = shift; |
965 | |
966 | return (grep $_->is_replicating, $self->replicants) == ($self->replicants); |
967 | } |
968 | |
969 | =head2 connect_call_datetime_setup |
970 | |
971 | calls L<DBIx::Class::Storage::DBI/connect_call_datetime_setup> for all storages |
972 | |
973 | =cut |
974 | |
975 | sub connect_call_datetime_setup { |
976 | my $self = shift; |
977 | $_->connect_call_datetime_setup for $self->all_storages; |
978 | } |
979 | |
980 | sub _populate_dbh { |
981 | my $self = shift; |
982 | $_->_populate_dbh for $self->all_storages; |
983 | } |
984 | |
985 | sub _connect { |
986 | my $self = shift; |
987 | $_->_connect for $self->all_storages; |
988 | } |
989 | |
990 | sub _rebless { |
991 | my $self = shift; |
992 | $_->_rebless for $self->all_storages; |
993 | } |
994 | |
995 | sub _determine_driver { |
996 | my $self = shift; |
997 | $_->_determine_driver for $self->all_storages; |
998 | } |
999 | |
1000 | sub _driver_determined { |
1001 | my $self = shift; |
fd323bf1 |
1002 | |
3244fdcc |
1003 | if (@_) { |
1004 | $_->_driver_determined(@_) for $self->all_storages; |
1005 | } |
1006 | |
1007 | return $self->master->_driver_determined; |
1008 | } |
1009 | |
1010 | sub _init { |
1011 | my $self = shift; |
fd323bf1 |
1012 | |
3244fdcc |
1013 | $_->_init for $self->all_storages; |
1014 | } |
1015 | |
1016 | sub _run_connection_actions { |
1017 | my $self = shift; |
fd323bf1 |
1018 | |
3244fdcc |
1019 | $_->_run_connection_actions for $self->all_storages; |
1020 | } |
1021 | |
1022 | sub _do_connection_actions { |
1023 | my $self = shift; |
fd323bf1 |
1024 | |
3244fdcc |
1025 | if (@_) { |
1026 | $_->_do_connection_actions(@_) for $self->all_storages; |
1027 | } |
1028 | } |
1029 | |
1030 | sub connect_call_do_sql { |
1031 | my $self = shift; |
1032 | $_->connect_call_do_sql(@_) for $self->all_storages; |
1033 | } |
1034 | |
1035 | sub disconnect_call_do_sql { |
1036 | my $self = shift; |
1037 | $_->disconnect_call_do_sql(@_) for $self->all_storages; |
1038 | } |
1039 | |
1040 | sub _seems_connected { |
1041 | my $self = shift; |
1042 | |
1043 | return min map $_->_seems_connected, $self->all_storages; |
1044 | } |
1045 | |
1046 | sub _ping { |
1047 | my $self = shift; |
1048 | |
1049 | return min map $_->_ping, $self->all_storages; |
1050 | } |
1051 | |
bbdda281 |
1052 | # not using the normalized_version, because we want to preserve |
1053 | # version numbers much longer than the conventional xxx.yyyzzz |
7da56142 |
1054 | my $numify_ver = sub { |
1055 | my $ver = shift; |
1056 | my @numparts = split /\D+/, $ver; |
bbdda281 |
1057 | my $format = '%d.' . (join '', ('%06d') x (@numparts - 1)); |
7da56142 |
1058 | |
1059 | return sprintf $format, @numparts; |
1060 | }; |
fecb38cb |
1061 | sub _server_info { |
1062 | my $self = shift; |
1063 | |
bbdda281 |
1064 | if (not $self->_dbh_details->{info}) { |
1065 | $self->_dbh_details->{info} = ( |
fd323bf1 |
1066 | reduce { $a->[0] < $b->[0] ? $a : $b } |
7da56142 |
1067 | map [ $numify_ver->($_->{dbms_version}), $_ ], |
1068 | map $_->_server_info, $self->all_storages |
1069 | )->[1]; |
fecb38cb |
1070 | } |
1071 | |
bbdda281 |
1072 | return $self->next::method; |
fecb38cb |
1073 | } |
1074 | |
1075 | sub _get_server_version { |
1076 | my $self = shift; |
1077 | |
1078 | return $self->_server_info->{dbms_version}; |
1079 | } |
1080 | |
7e38d850 |
1081 | =head1 GOTCHAS |
1082 | |
1083 | Due to the fact that replicants can lag behind a master, you must take care to |
1084 | make sure you use one of the methods to force read queries to a master should |
1085 | you need realtime data integrity. For example, if you insert a row, and then |
3dd506b8 |
1086 | immediately re-read it from the database (say, by doing |
1087 | L<< $result->discard_changes|DBIx::Class::Row/discard_changes >>) |
7e38d850 |
1088 | or you insert a row and then immediately build a query that expects that row |
1089 | to be an item, you should force the master to handle reads. Otherwise, due to |
1090 | the lag, there is no certainty your data will be in the expected state. |
1091 | |
1092 | For data integrity, all transactions automatically use the master storage for |
1093 | all read and write queries. Using a transaction is the preferred and recommended |
1094 | method to force the master to handle all read queries. |
1095 | |
1096 | Otherwise, you can force a single query to use the master with the 'force_pool' |
1097 | attribute: |
1098 | |
47d7b769 |
1099 | my $result = $resultset->search(undef, {force_pool=>'master'})->find($pk); |
7e38d850 |
1100 | |
b1de1b06 |
1101 | This attribute will safely be ignored by non replicated storages, so you can use |
7e38d850 |
1102 | the same code for both types of systems. |
1103 | |
1104 | Lastly, you can use the L</execute_reliably> method, which works very much like |
1105 | a transaction. |
1106 | |
1107 | For debugging, you can turn replication on/off with the methods L</set_reliable_storage> |
1108 | and L</set_balanced_storage>, however this operates at a global level and is not |
1109 | suitable if you have a shared Schema object being used by multiple processes, |
1110 | such as on a web application server. You can get around this limitation by |
1111 | using the Schema clone method. |
1112 | |
1113 | my $new_schema = $schema->clone; |
1114 | $new_schema->set_reliable_storage; |
d4daee7b |
1115 | |
7e38d850 |
1116 | ## $new_schema will use only the Master storage for all reads/writes while |
1117 | ## the $schema object will use replicated storage. |
1118 | |
a2bd3796 |
1119 | =head1 FURTHER QUESTIONS? |
f5d3a5de |
1120 | |
a2bd3796 |
1121 | Check the list of L<additional DBIC resources|DBIx::Class/GETTING HELP/SUPPORT>. |
2156bbdd |
1122 | |
a2bd3796 |
1123 | =head1 COPYRIGHT AND LICENSE |
f5d3a5de |
1124 | |
a2bd3796 |
1125 | This module is free software L<copyright|DBIx::Class/COPYRIGHT AND LICENSE> |
1126 | by the L<DBIx::Class (DBIC) authors|DBIx::Class/AUTHORS>. You can |
1127 | redistribute it and/or modify it under the same terms as the |
1128 | L<DBIx::Class library|DBIx::Class/COPYRIGHT AND LICENSE>. |
f5d3a5de |
1129 | |
1130 | =cut |
1131 | |
c354902c |
1132 | __PACKAGE__->meta->make_immutable; |
1133 | |
f5d3a5de |
1134 | 1; |