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1 | package DBIx::Class::Storage::DBI::Replicated; |
f5d3a5de |
2 | |
ecb65397 |
3 | BEGIN { |
4 | use Carp::Clan qw/^DBIx::Class/; |
5 | |
6 | ## Modules required for Replication support not required for general DBIC |
7 | ## use, so we explicitly test for these. |
8 | |
9 | my %replication_required = ( |
9901aad7 |
10 | Moose => '0.77', |
ecb65397 |
11 | MooseX::AttributeHelpers => '0.12', |
9901aad7 |
12 | MooseX::Types => '0.10', |
13 | namespace::clean => '0.11', |
ecb65397 |
14 | ); |
15 | |
16 | my @didnt_load; |
17 | |
18 | for my $module (keys %replication_required) { |
19 | eval "use $module $replication_required{$module}"; |
20 | push @didnt_load, "$module $replication_required{$module}" |
21 | if $@; |
22 | } |
23 | |
24 | croak("@{[ join ', ', @didnt_load ]} are missing and are required for Replication") |
25 | if @didnt_load; |
26 | } |
27 | |
26ab719a |
28 | use DBIx::Class::Storage::DBI; |
2bf79155 |
29 | use DBIx::Class::Storage::DBI::Replicated::Pool; |
26ab719a |
30 | use DBIx::Class::Storage::DBI::Replicated::Balancer; |
9901aad7 |
31 | use DBIx::Class::Storage::DBI::Replicated::Types 'BalancerClassNamePart'; |
41916570 |
32 | use MooseX::Types::Moose qw/ClassName HashRef Object/; |
9901aad7 |
33 | |
34 | use namespace::clean -except => 'meta'; |
2bf79155 |
35 | |
36 | =head1 NAME |
37 | |
ecb65397 |
38 | DBIx::Class::Storage::DBI::Replicated - BETA Replicated database support |
2bf79155 |
39 | |
40 | =head1 SYNOPSIS |
41 | |
42 | The Following example shows how to change an existing $schema to a replicated |
43 | storage type, add some replicated (readonly) databases, and perform reporting |
955a6df6 |
44 | tasks. |
2bf79155 |
45 | |
64cdad22 |
46 | ## Change storage_type in your schema class |
47 | $schema->storage_type( ['::DBI::Replicated', {balancer=>'::Random'}] ); |
48 | |
49 | ## Add some slaves. Basically this is an array of arrayrefs, where each |
50 | ## arrayref is database connect information |
51 | |
52 | $schema->storage->connect_replicants( |
53 | [$dsn1, $user, $pass, \%opts], |
54 | [$dsn2, $user, $pass, \%opts], |
55 | [$dsn3, $user, $pass, \%opts], |
56 | ); |
57 | |
7e38d850 |
58 | ## Now, just use the $schema as normal |
59 | $schema->resultset('Source')->search({name=>'etc'}); |
60 | |
61 | ## You can force a given query to use a particular storage using the search |
62 | ### attribute 'force_pool'. For example: |
63 | |
64 | my $RS = $schema->resultset('Source')->search(undef, {force_pool=>'master'}); |
65 | |
66 | ## Now $RS will force everything (both reads and writes) to use whatever was |
67 | ## setup as the master storage. 'master' is hardcoded to always point to the |
68 | ## Master, but you can also use any Replicant name. Please see: |
69 | ## L<DBIx::Class::Storage::Replicated::Pool> and the replicants attribute for |
70 | ## More. Also see transactions and L</execute_reliably> for alternative ways |
71 | ## to force read traffic to the master. |
72 | |
2bf79155 |
73 | =head1 DESCRIPTION |
74 | |
7e38d850 |
75 | Warning: This class is marked BETA. This has been running a production |
ccb3b897 |
76 | website using MySQL native replication as its backend and we have some decent |
7e38d850 |
77 | test coverage but the code hasn't yet been stressed by a variety of databases. |
78 | Individual DB's may have quirks we are not aware of. Please use this in first |
79 | development and pass along your experiences/bug fixes. |
2bf79155 |
80 | |
81 | This class implements replicated data store for DBI. Currently you can define |
82 | one master and numerous slave database connections. All write-type queries |
83 | (INSERT, UPDATE, DELETE and even LAST_INSERT_ID) are routed to master |
84 | database, all read-type queries (SELECTs) go to the slave database. |
85 | |
86 | Basically, any method request that L<DBIx::Class::Storage::DBI> would normally |
bca099a3 |
87 | handle gets delegated to one of the two attributes: L</read_handler> or to |
88 | L</write_handler>. Additionally, some methods need to be distributed |
2bf79155 |
89 | to all existing storages. This way our storage class is a drop in replacement |
90 | for L<DBIx::Class::Storage::DBI>. |
91 | |
92 | Read traffic is spread across the replicants (slaves) occuring to a user |
93 | selected algorithm. The default algorithm is random weighted. |
94 | |
bca099a3 |
95 | =head1 NOTES |
96 | |
97 | The consistancy betweeen master and replicants is database specific. The Pool |
98 | gives you a method to validate it's replicants, removing and replacing them |
7e38d850 |
99 | when they fail/pass predefined criteria. Please make careful use of the ways |
ecb65397 |
100 | to force a query to run against Master when needed. |
101 | |
102 | =head1 REQUIREMENTS |
103 | |
104 | Replicated Storage has additional requirements not currently part of L<DBIx::Class> |
105 | |
9901aad7 |
106 | Moose => 0.77 |
ecb65397 |
107 | MooseX::AttributeHelpers => 0.12 |
9901aad7 |
108 | MooseX::Types => 0.10 |
109 | namespace::clean => 0.11 |
ecb65397 |
110 | |
111 | You will need to install these modules manually via CPAN or make them part of the |
112 | Makefile for your distribution. |
2bf79155 |
113 | |
114 | =head1 ATTRIBUTES |
115 | |
116 | This class defines the following attributes. |
117 | |
2ce6e9a6 |
118 | =head2 schema |
119 | |
120 | The underlying L<DBIx::Class::Schema> object this storage is attaching |
121 | |
122 | =cut |
123 | |
124 | has 'schema' => ( |
125 | is=>'rw', |
126 | isa=>'DBIx::Class::Schema', |
127 | weak_ref=>1, |
128 | required=>1, |
129 | ); |
130 | |
26ab719a |
131 | =head2 pool_type |
2bf79155 |
132 | |
26ab719a |
133 | Contains the classname which will instantiate the L</pool> object. Defaults |
134 | to: L<DBIx::Class::Storage::DBI::Replicated::Pool>. |
2bf79155 |
135 | |
136 | =cut |
137 | |
26ab719a |
138 | has 'pool_type' => ( |
64cdad22 |
139 | is=>'ro', |
41916570 |
140 | isa=>ClassName, |
2ce6e9a6 |
141 | required=>1, |
142 | default=>'DBIx::Class::Storage::DBI::Replicated::Pool', |
64cdad22 |
143 | handles=>{ |
144 | 'create_pool' => 'new', |
145 | }, |
2bf79155 |
146 | ); |
147 | |
f068a139 |
148 | =head2 pool_args |
149 | |
150 | Contains a hashref of initialized information to pass to the Balancer object. |
151 | See L<DBIx::Class::Storage::Replicated::Pool> for available arguments. |
152 | |
153 | =cut |
154 | |
155 | has 'pool_args' => ( |
64cdad22 |
156 | is=>'ro', |
41916570 |
157 | isa=>HashRef, |
64cdad22 |
158 | lazy=>1, |
159 | required=>1, |
160 | default=>sub { {} }, |
f068a139 |
161 | ); |
162 | |
163 | |
26ab719a |
164 | =head2 balancer_type |
2bf79155 |
165 | |
166 | The replication pool requires a balance class to provider the methods for |
167 | choose how to spread the query load across each replicant in the pool. |
168 | |
169 | =cut |
170 | |
26ab719a |
171 | has 'balancer_type' => ( |
64cdad22 |
172 | is=>'ro', |
9901aad7 |
173 | isa=>BalancerClassNamePart, |
2ce6e9a6 |
174 | coerce=>1, |
175 | required=>1, |
176 | default=> 'DBIx::Class::Storage::DBI::Replicated::Balancer::First', |
64cdad22 |
177 | handles=>{ |
178 | 'create_balancer' => 'new', |
179 | }, |
2bf79155 |
180 | ); |
181 | |
17b05c13 |
182 | =head2 balancer_args |
183 | |
184 | Contains a hashref of initialized information to pass to the Balancer object. |
f068a139 |
185 | See L<DBIx::Class::Storage::Replicated::Balancer> for available arguments. |
17b05c13 |
186 | |
187 | =cut |
188 | |
189 | has 'balancer_args' => ( |
64cdad22 |
190 | is=>'ro', |
41916570 |
191 | isa=>HashRef, |
64cdad22 |
192 | lazy=>1, |
193 | required=>1, |
194 | default=>sub { {} }, |
17b05c13 |
195 | ); |
196 | |
26ab719a |
197 | =head2 pool |
2bf79155 |
198 | |
26ab719a |
199 | Is a <DBIx::Class::Storage::DBI::Replicated::Pool> or derived class. This is a |
200 | container class for one or more replicated databases. |
2bf79155 |
201 | |
202 | =cut |
203 | |
26ab719a |
204 | has 'pool' => ( |
64cdad22 |
205 | is=>'ro', |
206 | isa=>'DBIx::Class::Storage::DBI::Replicated::Pool', |
207 | lazy_build=>1, |
208 | handles=>[qw/ |
209 | connect_replicants |
210 | replicants |
211 | has_replicants |
212 | /], |
2bf79155 |
213 | ); |
214 | |
26ab719a |
215 | =head2 balancer |
2bf79155 |
216 | |
26ab719a |
217 | Is a <DBIx::Class::Storage::DBI::Replicated::Balancer> or derived class. This |
218 | is a class that takes a pool (<DBIx::Class::Storage::DBI::Replicated::Pool>) |
2bf79155 |
219 | |
26ab719a |
220 | =cut |
2bf79155 |
221 | |
26ab719a |
222 | has 'balancer' => ( |
64cdad22 |
223 | is=>'ro', |
224 | isa=>'DBIx::Class::Storage::DBI::Replicated::Balancer', |
225 | lazy_build=>1, |
226 | handles=>[qw/auto_validate_every/], |
26ab719a |
227 | ); |
2bf79155 |
228 | |
cb6ec758 |
229 | =head2 master |
230 | |
231 | The master defines the canonical state for a pool of connected databases. All |
232 | the replicants are expected to match this databases state. Thus, in a classic |
233 | Master / Slaves distributed system, all the slaves are expected to replicate |
234 | the Master's state as quick as possible. This is the only database in the |
235 | pool of databases that is allowed to handle write traffic. |
236 | |
237 | =cut |
238 | |
239 | has 'master' => ( |
64cdad22 |
240 | is=> 'ro', |
241 | isa=>'DBIx::Class::Storage::DBI', |
242 | lazy_build=>1, |
cb6ec758 |
243 | ); |
244 | |
cb6ec758 |
245 | =head1 ATTRIBUTES IMPLEMENTING THE DBIx::Storage::DBI INTERFACE |
246 | |
247 | The following methods are delegated all the methods required for the |
248 | L<DBIx::Class::Storage::DBI> interface. |
249 | |
250 | =head2 read_handler |
251 | |
252 | Defines an object that implements the read side of L<BIx::Class::Storage::DBI>. |
253 | |
254 | =cut |
255 | |
256 | has 'read_handler' => ( |
64cdad22 |
257 | is=>'rw', |
41916570 |
258 | isa=>Object, |
64cdad22 |
259 | lazy_build=>1, |
260 | handles=>[qw/ |
261 | select |
262 | select_single |
263 | columns_info_for |
264 | /], |
cb6ec758 |
265 | ); |
266 | |
cb6ec758 |
267 | =head2 write_handler |
268 | |
269 | Defines an object that implements the write side of L<BIx::Class::Storage::DBI>. |
270 | |
271 | =cut |
272 | |
273 | has 'write_handler' => ( |
64cdad22 |
274 | is=>'ro', |
41916570 |
275 | isa=>Object, |
64cdad22 |
276 | lazy_build=>1, |
277 | lazy_build=>1, |
278 | handles=>[qw/ |
279 | on_connect_do |
280 | on_disconnect_do |
281 | connect_info |
282 | throw_exception |
283 | sql_maker |
284 | sqlt_type |
285 | create_ddl_dir |
286 | deployment_statements |
287 | datetime_parser |
288 | datetime_parser_type |
289 | last_insert_id |
290 | insert |
291 | insert_bulk |
292 | update |
293 | delete |
294 | dbh |
2ce6e9a6 |
295 | txn_begin |
64cdad22 |
296 | txn_do |
297 | txn_commit |
298 | txn_rollback |
2ce6e9a6 |
299 | txn_scope_guard |
64cdad22 |
300 | sth |
301 | deploy |
0180bef9 |
302 | with_deferred_fk_checks |
2ce6e9a6 |
303 | |
64cdad22 |
304 | reload_row |
2ce6e9a6 |
305 | _prep_for_execute |
2ce6e9a6 |
306 | |
64cdad22 |
307 | /], |
cb6ec758 |
308 | ); |
309 | |
26ab719a |
310 | =head1 METHODS |
2bf79155 |
311 | |
26ab719a |
312 | This class defines the following methods. |
2bf79155 |
313 | |
c354902c |
314 | =head2 BUILDARGS |
2bf79155 |
315 | |
cb6ec758 |
316 | L<DBIx::Class::Schema> when instantiating it's storage passed itself as the |
2ce6e9a6 |
317 | first argument. So we need to massage the arguments a bit so that all the |
318 | bits get put into the correct places. |
2bf79155 |
319 | |
320 | =cut |
321 | |
c354902c |
322 | sub BUILDARGS { |
323 | my ($class, $schema, $storage_type_args, @args) = @_; |
324 | |
325 | return { |
326 | schema=>$schema, |
327 | %$storage_type_args, |
328 | @args |
329 | } |
330 | } |
2bf79155 |
331 | |
cb6ec758 |
332 | =head2 _build_master |
2bf79155 |
333 | |
cb6ec758 |
334 | Lazy builder for the L</master> attribute. |
2bf79155 |
335 | |
336 | =cut |
337 | |
cb6ec758 |
338 | sub _build_master { |
2ce6e9a6 |
339 | my $self = shift @_; |
340 | DBIx::Class::Storage::DBI->new($self->schema); |
106d5f3b |
341 | } |
342 | |
26ab719a |
343 | =head2 _build_pool |
2bf79155 |
344 | |
26ab719a |
345 | Lazy builder for the L</pool> attribute. |
2bf79155 |
346 | |
347 | =cut |
348 | |
26ab719a |
349 | sub _build_pool { |
64cdad22 |
350 | my $self = shift @_; |
351 | $self->create_pool(%{$self->pool_args}); |
2bf79155 |
352 | } |
353 | |
26ab719a |
354 | =head2 _build_balancer |
2bf79155 |
355 | |
cb6ec758 |
356 | Lazy builder for the L</balancer> attribute. This takes a Pool object so that |
357 | the balancer knows which pool it's balancing. |
2bf79155 |
358 | |
359 | =cut |
360 | |
26ab719a |
361 | sub _build_balancer { |
64cdad22 |
362 | my $self = shift @_; |
363 | $self->create_balancer( |
364 | pool=>$self->pool, |
365 | master=>$self->master, |
366 | %{$self->balancer_args}, |
367 | ); |
2bf79155 |
368 | } |
369 | |
cb6ec758 |
370 | =head2 _build_write_handler |
2bf79155 |
371 | |
cb6ec758 |
372 | Lazy builder for the L</write_handler> attribute. The default is to set this to |
373 | the L</master>. |
50336325 |
374 | |
375 | =cut |
376 | |
cb6ec758 |
377 | sub _build_write_handler { |
64cdad22 |
378 | return shift->master; |
cb6ec758 |
379 | } |
50336325 |
380 | |
cb6ec758 |
381 | =head2 _build_read_handler |
2bf79155 |
382 | |
cb6ec758 |
383 | Lazy builder for the L</read_handler> attribute. The default is to set this to |
384 | the L</balancer>. |
2bf79155 |
385 | |
386 | =cut |
387 | |
cb6ec758 |
388 | sub _build_read_handler { |
64cdad22 |
389 | return shift->balancer; |
cb6ec758 |
390 | } |
50336325 |
391 | |
cb6ec758 |
392 | =head2 around: connect_replicants |
2bf79155 |
393 | |
cb6ec758 |
394 | All calls to connect_replicants needs to have an existing $schema tacked onto |
395 | top of the args, since L<DBIx::Storage::DBI> needs it. |
955a6df6 |
396 | |
cb6ec758 |
397 | =cut |
955a6df6 |
398 | |
cb6ec758 |
399 | around 'connect_replicants' => sub { |
64cdad22 |
400 | my ($method, $self, @args) = @_; |
401 | $self->$method($self->schema, @args); |
955a6df6 |
402 | }; |
2bf79155 |
403 | |
2bf79155 |
404 | =head2 all_storages |
405 | |
406 | Returns an array of of all the connected storage backends. The first element |
407 | in the returned array is the master, and the remainings are each of the |
408 | replicants. |
409 | |
410 | =cut |
411 | |
412 | sub all_storages { |
64cdad22 |
413 | my $self = shift @_; |
414 | return grep {defined $_ && blessed $_} ( |
415 | $self->master, |
6412a592 |
416 | values %{ $self->replicants }, |
64cdad22 |
417 | ); |
2bf79155 |
418 | } |
419 | |
c4d3fae2 |
420 | =head2 execute_reliably ($coderef, ?@args) |
421 | |
422 | Given a coderef, saves the current state of the L</read_handler>, forces it to |
423 | use reliable storage (ie sets it to the master), executes a coderef and then |
424 | restores the original state. |
425 | |
426 | Example: |
427 | |
64cdad22 |
428 | my $reliably = sub { |
429 | my $name = shift @_; |
430 | $schema->resultset('User')->create({name=>$name}); |
431 | my $user_rs = $schema->resultset('User')->find({name=>$name}); |
432 | return $user_rs; |
433 | }; |
c4d3fae2 |
434 | |
64cdad22 |
435 | my $user_rs = $schema->storage->execute_reliably($reliably, 'John'); |
c4d3fae2 |
436 | |
437 | Use this when you must be certain of your database state, such as when you just |
438 | inserted something and need to get a resultset including it, etc. |
439 | |
440 | =cut |
441 | |
442 | sub execute_reliably { |
64cdad22 |
443 | my ($self, $coderef, @args) = @_; |
444 | |
445 | unless( ref $coderef eq 'CODE') { |
446 | $self->throw_exception('Second argument must be a coderef'); |
447 | } |
448 | |
449 | ##Get copy of master storage |
450 | my $master = $self->master; |
451 | |
452 | ##Get whatever the current read hander is |
453 | my $current = $self->read_handler; |
454 | |
455 | ##Set the read handler to master |
456 | $self->read_handler($master); |
457 | |
458 | ## do whatever the caller needs |
459 | my @result; |
460 | my $want_array = wantarray; |
461 | |
462 | eval { |
463 | if($want_array) { |
464 | @result = $coderef->(@args); |
465 | } elsif(defined $want_array) { |
466 | ($result[0]) = ($coderef->(@args)); |
ed213e85 |
467 | } else { |
64cdad22 |
468 | $coderef->(@args); |
469 | } |
470 | }; |
471 | |
472 | ##Reset to the original state |
473 | $self->read_handler($current); |
474 | |
475 | ##Exception testing has to come last, otherwise you might leave the |
476 | ##read_handler set to master. |
477 | |
478 | if($@) { |
479 | $self->throw_exception("coderef returned an error: $@"); |
480 | } else { |
481 | return $want_array ? @result : $result[0]; |
482 | } |
c4d3fae2 |
483 | } |
484 | |
cb6ec758 |
485 | =head2 set_reliable_storage |
486 | |
487 | Sets the current $schema to be 'reliable', that is all queries, both read and |
488 | write are sent to the master |
64cdad22 |
489 | |
cb6ec758 |
490 | =cut |
491 | |
492 | sub set_reliable_storage { |
64cdad22 |
493 | my $self = shift @_; |
494 | my $schema = $self->schema; |
495 | my $write_handler = $self->schema->storage->write_handler; |
496 | |
497 | $schema->storage->read_handler($write_handler); |
cb6ec758 |
498 | } |
499 | |
500 | =head2 set_balanced_storage |
501 | |
502 | Sets the current $schema to be use the </balancer> for all reads, while all |
503 | writea are sent to the master only |
64cdad22 |
504 | |
cb6ec758 |
505 | =cut |
506 | |
507 | sub set_balanced_storage { |
64cdad22 |
508 | my $self = shift @_; |
509 | my $schema = $self->schema; |
510 | my $write_handler = $self->schema->storage->balancer; |
511 | |
512 | $schema->storage->read_handler($write_handler); |
cb6ec758 |
513 | } |
2bf79155 |
514 | |
6834cc1d |
515 | =head2 around: txn_do ($coderef) |
c4d3fae2 |
516 | |
517 | Overload to the txn_do method, which is delegated to whatever the |
518 | L<write_handler> is set to. We overload this in order to wrap in inside a |
519 | L</execute_reliably> method. |
520 | |
521 | =cut |
522 | |
6834cc1d |
523 | around 'txn_do' => sub { |
64cdad22 |
524 | my($txn_do, $self, $coderef, @args) = @_; |
525 | $self->execute_reliably(sub {$self->$txn_do($coderef, @args)}); |
6834cc1d |
526 | }; |
c4d3fae2 |
527 | |
2bf79155 |
528 | =head2 connected |
529 | |
530 | Check that the master and at least one of the replicants is connected. |
531 | |
532 | =cut |
533 | |
534 | sub connected { |
64cdad22 |
535 | my $self = shift @_; |
536 | return |
537 | $self->master->connected && |
538 | $self->pool->connected_replicants; |
2bf79155 |
539 | } |
540 | |
2bf79155 |
541 | =head2 ensure_connected |
542 | |
543 | Make sure all the storages are connected. |
544 | |
545 | =cut |
546 | |
547 | sub ensure_connected { |
64cdad22 |
548 | my $self = shift @_; |
549 | foreach my $source ($self->all_storages) { |
550 | $source->ensure_connected(@_); |
551 | } |
2bf79155 |
552 | } |
553 | |
2bf79155 |
554 | =head2 limit_dialect |
555 | |
556 | Set the limit_dialect for all existing storages |
557 | |
558 | =cut |
559 | |
560 | sub limit_dialect { |
64cdad22 |
561 | my $self = shift @_; |
562 | foreach my $source ($self->all_storages) { |
563 | $source->limit_dialect(@_); |
564 | } |
3fbe08e3 |
565 | return $self->master->quote_char; |
2bf79155 |
566 | } |
567 | |
2bf79155 |
568 | =head2 quote_char |
569 | |
570 | Set the quote_char for all existing storages |
571 | |
572 | =cut |
573 | |
574 | sub quote_char { |
64cdad22 |
575 | my $self = shift @_; |
576 | foreach my $source ($self->all_storages) { |
577 | $source->quote_char(@_); |
578 | } |
3fbe08e3 |
579 | return $self->master->quote_char; |
2bf79155 |
580 | } |
581 | |
2bf79155 |
582 | =head2 name_sep |
583 | |
584 | Set the name_sep for all existing storages |
585 | |
586 | =cut |
587 | |
588 | sub name_sep { |
64cdad22 |
589 | my $self = shift @_; |
590 | foreach my $source ($self->all_storages) { |
591 | $source->name_sep(@_); |
592 | } |
3fbe08e3 |
593 | return $self->master->name_sep; |
2bf79155 |
594 | } |
595 | |
2bf79155 |
596 | =head2 set_schema |
597 | |
598 | Set the schema object for all existing storages |
599 | |
600 | =cut |
601 | |
602 | sub set_schema { |
64cdad22 |
603 | my $self = shift @_; |
604 | foreach my $source ($self->all_storages) { |
605 | $source->set_schema(@_); |
606 | } |
2bf79155 |
607 | } |
608 | |
2bf79155 |
609 | =head2 debug |
610 | |
611 | set a debug flag across all storages |
612 | |
613 | =cut |
614 | |
615 | sub debug { |
64cdad22 |
616 | my $self = shift @_; |
3fbe08e3 |
617 | if(@_) { |
618 | foreach my $source ($self->all_storages) { |
619 | $source->debug(@_); |
620 | } |
64cdad22 |
621 | } |
3fbe08e3 |
622 | return $self->master->debug; |
2bf79155 |
623 | } |
624 | |
2bf79155 |
625 | =head2 debugobj |
626 | |
627 | set a debug object across all storages |
628 | |
629 | =cut |
630 | |
631 | sub debugobj { |
64cdad22 |
632 | my $self = shift @_; |
3fbe08e3 |
633 | if(@_) { |
634 | foreach my $source ($self->all_storages) { |
635 | $source->debugobj(@_); |
636 | } |
64cdad22 |
637 | } |
3fbe08e3 |
638 | return $self->master->debugobj; |
2bf79155 |
639 | } |
640 | |
2bf79155 |
641 | =head2 debugfh |
642 | |
643 | set a debugfh object across all storages |
644 | |
645 | =cut |
646 | |
647 | sub debugfh { |
64cdad22 |
648 | my $self = shift @_; |
3fbe08e3 |
649 | if(@_) { |
650 | foreach my $source ($self->all_storages) { |
651 | $source->debugfh(@_); |
652 | } |
64cdad22 |
653 | } |
3fbe08e3 |
654 | return $self->master->debugfh; |
2bf79155 |
655 | } |
656 | |
2bf79155 |
657 | =head2 debugcb |
658 | |
659 | set a debug callback across all storages |
660 | |
661 | =cut |
662 | |
663 | sub debugcb { |
64cdad22 |
664 | my $self = shift @_; |
3fbe08e3 |
665 | if(@_) { |
666 | foreach my $source ($self->all_storages) { |
667 | $source->debugcb(@_); |
668 | } |
64cdad22 |
669 | } |
3fbe08e3 |
670 | return $self->master->debugcb; |
2bf79155 |
671 | } |
672 | |
2bf79155 |
673 | =head2 disconnect |
674 | |
675 | disconnect everything |
676 | |
677 | =cut |
678 | |
679 | sub disconnect { |
64cdad22 |
680 | my $self = shift @_; |
681 | foreach my $source ($self->all_storages) { |
682 | $source->disconnect(@_); |
683 | } |
2bf79155 |
684 | } |
685 | |
7e38d850 |
686 | =head1 GOTCHAS |
687 | |
688 | Due to the fact that replicants can lag behind a master, you must take care to |
689 | make sure you use one of the methods to force read queries to a master should |
690 | you need realtime data integrity. For example, if you insert a row, and then |
691 | immediately re-read it from the database (say, by doing $row->discard_changes) |
692 | or you insert a row and then immediately build a query that expects that row |
693 | to be an item, you should force the master to handle reads. Otherwise, due to |
694 | the lag, there is no certainty your data will be in the expected state. |
695 | |
696 | For data integrity, all transactions automatically use the master storage for |
697 | all read and write queries. Using a transaction is the preferred and recommended |
698 | method to force the master to handle all read queries. |
699 | |
700 | Otherwise, you can force a single query to use the master with the 'force_pool' |
701 | attribute: |
702 | |
703 | my $row = $resultset->search(undef, {force_pool=>'master'})->find($pk); |
704 | |
705 | This attribute will safely be ignore by non replicated storages, so you can use |
706 | the same code for both types of systems. |
707 | |
708 | Lastly, you can use the L</execute_reliably> method, which works very much like |
709 | a transaction. |
710 | |
711 | For debugging, you can turn replication on/off with the methods L</set_reliable_storage> |
712 | and L</set_balanced_storage>, however this operates at a global level and is not |
713 | suitable if you have a shared Schema object being used by multiple processes, |
714 | such as on a web application server. You can get around this limitation by |
715 | using the Schema clone method. |
716 | |
717 | my $new_schema = $schema->clone; |
718 | $new_schema->set_reliable_storage; |
719 | |
720 | ## $new_schema will use only the Master storage for all reads/writes while |
721 | ## the $schema object will use replicated storage. |
722 | |
f5d3a5de |
723 | =head1 AUTHOR |
724 | |
64cdad22 |
725 | John Napiorkowski <john.napiorkowski@takkle.com> |
f5d3a5de |
726 | |
c4d3fae2 |
727 | Based on code originated by: |
f5d3a5de |
728 | |
64cdad22 |
729 | Norbert Csongrádi <bert@cpan.org> |
730 | Peter Siklósi <einon@einon.hu> |
2156bbdd |
731 | |
f5d3a5de |
732 | =head1 LICENSE |
733 | |
734 | You may distribute this code under the same terms as Perl itself. |
735 | |
736 | =cut |
737 | |
c354902c |
738 | __PACKAGE__->meta->make_immutable; |
739 | |
f5d3a5de |
740 | 1; |