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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 = ( |
10 | Moose => '0.54', |
11 | MooseX::AttributeHelpers => '0.12', |
12 | Moose::Util::TypeConstraints => '0.54', |
13 | Class::MOP => '0.63', |
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; |
2bf79155 |
31 | |
32 | =head1 NAME |
33 | |
ecb65397 |
34 | DBIx::Class::Storage::DBI::Replicated - BETA Replicated database support |
2bf79155 |
35 | |
36 | =head1 SYNOPSIS |
37 | |
38 | The Following example shows how to change an existing $schema to a replicated |
39 | storage type, add some replicated (readonly) databases, and perform reporting |
955a6df6 |
40 | tasks. |
2bf79155 |
41 | |
64cdad22 |
42 | ## Change storage_type in your schema class |
43 | $schema->storage_type( ['::DBI::Replicated', {balancer=>'::Random'}] ); |
44 | |
45 | ## Add some slaves. Basically this is an array of arrayrefs, where each |
46 | ## arrayref is database connect information |
47 | |
48 | $schema->storage->connect_replicants( |
49 | [$dsn1, $user, $pass, \%opts], |
50 | [$dsn2, $user, $pass, \%opts], |
51 | [$dsn3, $user, $pass, \%opts], |
52 | ); |
53 | |
7e38d850 |
54 | ## Now, just use the $schema as normal |
55 | $schema->resultset('Source')->search({name=>'etc'}); |
56 | |
57 | ## You can force a given query to use a particular storage using the search |
58 | ### attribute 'force_pool'. For example: |
59 | |
60 | my $RS = $schema->resultset('Source')->search(undef, {force_pool=>'master'}); |
61 | |
62 | ## Now $RS will force everything (both reads and writes) to use whatever was |
63 | ## setup as the master storage. 'master' is hardcoded to always point to the |
64 | ## Master, but you can also use any Replicant name. Please see: |
65 | ## L<DBIx::Class::Storage::Replicated::Pool> and the replicants attribute for |
66 | ## More. Also see transactions and L</execute_reliably> for alternative ways |
67 | ## to force read traffic to the master. |
68 | |
2bf79155 |
69 | =head1 DESCRIPTION |
70 | |
7e38d850 |
71 | Warning: This class is marked BETA. This has been running a production |
ccb3b897 |
72 | website using MySQL native replication as its backend and we have some decent |
7e38d850 |
73 | test coverage but the code hasn't yet been stressed by a variety of databases. |
74 | Individual DB's may have quirks we are not aware of. Please use this in first |
75 | development and pass along your experiences/bug fixes. |
2bf79155 |
76 | |
77 | This class implements replicated data store for DBI. Currently you can define |
78 | one master and numerous slave database connections. All write-type queries |
79 | (INSERT, UPDATE, DELETE and even LAST_INSERT_ID) are routed to master |
80 | database, all read-type queries (SELECTs) go to the slave database. |
81 | |
82 | Basically, any method request that L<DBIx::Class::Storage::DBI> would normally |
bca099a3 |
83 | handle gets delegated to one of the two attributes: L</read_handler> or to |
84 | L</write_handler>. Additionally, some methods need to be distributed |
2bf79155 |
85 | to all existing storages. This way our storage class is a drop in replacement |
86 | for L<DBIx::Class::Storage::DBI>. |
87 | |
88 | Read traffic is spread across the replicants (slaves) occuring to a user |
89 | selected algorithm. The default algorithm is random weighted. |
90 | |
bca099a3 |
91 | =head1 NOTES |
92 | |
93 | The consistancy betweeen master and replicants is database specific. The Pool |
94 | gives you a method to validate it's replicants, removing and replacing them |
7e38d850 |
95 | when they fail/pass predefined criteria. Please make careful use of the ways |
ecb65397 |
96 | to force a query to run against Master when needed. |
97 | |
98 | =head1 REQUIREMENTS |
99 | |
100 | Replicated Storage has additional requirements not currently part of L<DBIx::Class> |
101 | |
e3c2b86d |
102 | Moose => 0.54 |
ecb65397 |
103 | MooseX::AttributeHelpers => 0.12 |
104 | Moose::Util::TypeConstraints => 0.54 |
105 | Class::MOP => 0.63 |
106 | |
107 | You will need to install these modules manually via CPAN or make them part of the |
108 | Makefile for your distribution. |
2bf79155 |
109 | |
110 | =head1 ATTRIBUTES |
111 | |
112 | This class defines the following attributes. |
113 | |
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114 | =head2 schema |
115 | |
116 | The underlying L<DBIx::Class::Schema> object this storage is attaching |
117 | |
118 | =cut |
119 | |
120 | has 'schema' => ( |
121 | is=>'rw', |
122 | isa=>'DBIx::Class::Schema', |
123 | weak_ref=>1, |
124 | required=>1, |
125 | ); |
126 | |
26ab719a |
127 | =head2 pool_type |
2bf79155 |
128 | |
26ab719a |
129 | Contains the classname which will instantiate the L</pool> object. Defaults |
130 | to: L<DBIx::Class::Storage::DBI::Replicated::Pool>. |
2bf79155 |
131 | |
132 | =cut |
133 | |
26ab719a |
134 | has 'pool_type' => ( |
64cdad22 |
135 | is=>'ro', |
136 | isa=>'ClassName', |
2ce6e9a6 |
137 | required=>1, |
138 | default=>'DBIx::Class::Storage::DBI::Replicated::Pool', |
64cdad22 |
139 | handles=>{ |
140 | 'create_pool' => 'new', |
141 | }, |
2bf79155 |
142 | ); |
143 | |
f068a139 |
144 | =head2 pool_args |
145 | |
146 | Contains a hashref of initialized information to pass to the Balancer object. |
147 | See L<DBIx::Class::Storage::Replicated::Pool> for available arguments. |
148 | |
149 | =cut |
150 | |
151 | has 'pool_args' => ( |
64cdad22 |
152 | is=>'ro', |
153 | isa=>'HashRef', |
154 | lazy=>1, |
155 | required=>1, |
156 | default=>sub { {} }, |
f068a139 |
157 | ); |
158 | |
159 | |
26ab719a |
160 | =head2 balancer_type |
2bf79155 |
161 | |
162 | The replication pool requires a balance class to provider the methods for |
163 | choose how to spread the query load across each replicant in the pool. |
164 | |
165 | =cut |
166 | |
2ce6e9a6 |
167 | subtype 'DBIx::Class::Storage::DBI::Replicated::BalancerClassNamePart', |
168 | as 'ClassName'; |
169 | |
170 | coerce 'DBIx::Class::Storage::DBI::Replicated::BalancerClassNamePart', |
171 | from 'Str', |
172 | via { |
173 | my $type = $_; |
174 | if($type=~m/^::/) { |
175 | $type = 'DBIx::Class::Storage::DBI::Replicated::Balancer'.$type; |
176 | } |
177 | Class::MOP::load_class($type); |
178 | $type; |
179 | }; |
180 | |
26ab719a |
181 | has 'balancer_type' => ( |
64cdad22 |
182 | is=>'ro', |
2ce6e9a6 |
183 | isa=>'DBIx::Class::Storage::DBI::Replicated::BalancerClassNamePart', |
184 | coerce=>1, |
185 | required=>1, |
186 | default=> 'DBIx::Class::Storage::DBI::Replicated::Balancer::First', |
64cdad22 |
187 | handles=>{ |
188 | 'create_balancer' => 'new', |
189 | }, |
2bf79155 |
190 | ); |
191 | |
17b05c13 |
192 | =head2 balancer_args |
193 | |
194 | Contains a hashref of initialized information to pass to the Balancer object. |
f068a139 |
195 | See L<DBIx::Class::Storage::Replicated::Balancer> for available arguments. |
17b05c13 |
196 | |
197 | =cut |
198 | |
199 | has 'balancer_args' => ( |
64cdad22 |
200 | is=>'ro', |
201 | isa=>'HashRef', |
202 | lazy=>1, |
203 | required=>1, |
204 | default=>sub { {} }, |
17b05c13 |
205 | ); |
206 | |
26ab719a |
207 | =head2 pool |
2bf79155 |
208 | |
26ab719a |
209 | Is a <DBIx::Class::Storage::DBI::Replicated::Pool> or derived class. This is a |
210 | container class for one or more replicated databases. |
2bf79155 |
211 | |
212 | =cut |
213 | |
26ab719a |
214 | has 'pool' => ( |
64cdad22 |
215 | is=>'ro', |
216 | isa=>'DBIx::Class::Storage::DBI::Replicated::Pool', |
217 | lazy_build=>1, |
218 | handles=>[qw/ |
219 | connect_replicants |
220 | replicants |
221 | has_replicants |
222 | /], |
2bf79155 |
223 | ); |
224 | |
26ab719a |
225 | =head2 balancer |
2bf79155 |
226 | |
26ab719a |
227 | Is a <DBIx::Class::Storage::DBI::Replicated::Balancer> or derived class. This |
228 | is a class that takes a pool (<DBIx::Class::Storage::DBI::Replicated::Pool>) |
2bf79155 |
229 | |
26ab719a |
230 | =cut |
2bf79155 |
231 | |
26ab719a |
232 | has 'balancer' => ( |
64cdad22 |
233 | is=>'ro', |
234 | isa=>'DBIx::Class::Storage::DBI::Replicated::Balancer', |
235 | lazy_build=>1, |
236 | handles=>[qw/auto_validate_every/], |
26ab719a |
237 | ); |
2bf79155 |
238 | |
cb6ec758 |
239 | =head2 master |
240 | |
241 | The master defines the canonical state for a pool of connected databases. All |
242 | the replicants are expected to match this databases state. Thus, in a classic |
243 | Master / Slaves distributed system, all the slaves are expected to replicate |
244 | the Master's state as quick as possible. This is the only database in the |
245 | pool of databases that is allowed to handle write traffic. |
246 | |
247 | =cut |
248 | |
249 | has 'master' => ( |
64cdad22 |
250 | is=> 'ro', |
251 | isa=>'DBIx::Class::Storage::DBI', |
252 | lazy_build=>1, |
cb6ec758 |
253 | ); |
254 | |
cb6ec758 |
255 | =head1 ATTRIBUTES IMPLEMENTING THE DBIx::Storage::DBI INTERFACE |
256 | |
257 | The following methods are delegated all the methods required for the |
258 | L<DBIx::Class::Storage::DBI> interface. |
259 | |
260 | =head2 read_handler |
261 | |
262 | Defines an object that implements the read side of L<BIx::Class::Storage::DBI>. |
263 | |
264 | =cut |
265 | |
266 | has 'read_handler' => ( |
64cdad22 |
267 | is=>'rw', |
268 | isa=>'Object', |
269 | lazy_build=>1, |
270 | handles=>[qw/ |
271 | select |
272 | select_single |
273 | columns_info_for |
274 | /], |
cb6ec758 |
275 | ); |
276 | |
cb6ec758 |
277 | =head2 write_handler |
278 | |
279 | Defines an object that implements the write side of L<BIx::Class::Storage::DBI>. |
280 | |
281 | =cut |
282 | |
283 | has 'write_handler' => ( |
64cdad22 |
284 | is=>'ro', |
285 | isa=>'Object', |
286 | lazy_build=>1, |
287 | lazy_build=>1, |
288 | handles=>[qw/ |
289 | on_connect_do |
290 | on_disconnect_do |
291 | connect_info |
292 | throw_exception |
293 | sql_maker |
294 | sqlt_type |
295 | create_ddl_dir |
296 | deployment_statements |
297 | datetime_parser |
298 | datetime_parser_type |
299 | last_insert_id |
300 | insert |
301 | insert_bulk |
302 | update |
303 | delete |
304 | dbh |
2ce6e9a6 |
305 | txn_begin |
64cdad22 |
306 | txn_do |
307 | txn_commit |
308 | txn_rollback |
2ce6e9a6 |
309 | txn_scope_guard |
64cdad22 |
310 | sth |
311 | deploy |
0180bef9 |
312 | with_deferred_fk_checks |
2ce6e9a6 |
313 | |
64cdad22 |
314 | reload_row |
2ce6e9a6 |
315 | _prep_for_execute |
316 | configure_sqlt |
317 | |
64cdad22 |
318 | /], |
cb6ec758 |
319 | ); |
320 | |
26ab719a |
321 | =head1 METHODS |
2bf79155 |
322 | |
26ab719a |
323 | This class defines the following methods. |
2bf79155 |
324 | |
c354902c |
325 | =head2 BUILDARGS |
2bf79155 |
326 | |
cb6ec758 |
327 | L<DBIx::Class::Schema> when instantiating it's storage passed itself as the |
2ce6e9a6 |
328 | first argument. So we need to massage the arguments a bit so that all the |
329 | bits get put into the correct places. |
2bf79155 |
330 | |
331 | =cut |
332 | |
c354902c |
333 | sub BUILDARGS { |
334 | my ($class, $schema, $storage_type_args, @args) = @_; |
335 | |
336 | return { |
337 | schema=>$schema, |
338 | %$storage_type_args, |
339 | @args |
340 | } |
341 | } |
2bf79155 |
342 | |
cb6ec758 |
343 | =head2 _build_master |
2bf79155 |
344 | |
cb6ec758 |
345 | Lazy builder for the L</master> attribute. |
2bf79155 |
346 | |
347 | =cut |
348 | |
cb6ec758 |
349 | sub _build_master { |
2ce6e9a6 |
350 | my $self = shift @_; |
351 | DBIx::Class::Storage::DBI->new($self->schema); |
106d5f3b |
352 | } |
353 | |
26ab719a |
354 | =head2 _build_pool |
2bf79155 |
355 | |
26ab719a |
356 | Lazy builder for the L</pool> attribute. |
2bf79155 |
357 | |
358 | =cut |
359 | |
26ab719a |
360 | sub _build_pool { |
64cdad22 |
361 | my $self = shift @_; |
362 | $self->create_pool(%{$self->pool_args}); |
2bf79155 |
363 | } |
364 | |
26ab719a |
365 | =head2 _build_balancer |
2bf79155 |
366 | |
cb6ec758 |
367 | Lazy builder for the L</balancer> attribute. This takes a Pool object so that |
368 | the balancer knows which pool it's balancing. |
2bf79155 |
369 | |
370 | =cut |
371 | |
26ab719a |
372 | sub _build_balancer { |
64cdad22 |
373 | my $self = shift @_; |
374 | $self->create_balancer( |
375 | pool=>$self->pool, |
376 | master=>$self->master, |
377 | %{$self->balancer_args}, |
378 | ); |
2bf79155 |
379 | } |
380 | |
cb6ec758 |
381 | =head2 _build_write_handler |
2bf79155 |
382 | |
cb6ec758 |
383 | Lazy builder for the L</write_handler> attribute. The default is to set this to |
384 | the L</master>. |
50336325 |
385 | |
386 | =cut |
387 | |
cb6ec758 |
388 | sub _build_write_handler { |
64cdad22 |
389 | return shift->master; |
cb6ec758 |
390 | } |
50336325 |
391 | |
cb6ec758 |
392 | =head2 _build_read_handler |
2bf79155 |
393 | |
cb6ec758 |
394 | Lazy builder for the L</read_handler> attribute. The default is to set this to |
395 | the L</balancer>. |
2bf79155 |
396 | |
397 | =cut |
398 | |
cb6ec758 |
399 | sub _build_read_handler { |
64cdad22 |
400 | return shift->balancer; |
cb6ec758 |
401 | } |
50336325 |
402 | |
cb6ec758 |
403 | =head2 around: connect_replicants |
2bf79155 |
404 | |
cb6ec758 |
405 | All calls to connect_replicants needs to have an existing $schema tacked onto |
406 | top of the args, since L<DBIx::Storage::DBI> needs it. |
955a6df6 |
407 | |
cb6ec758 |
408 | =cut |
955a6df6 |
409 | |
cb6ec758 |
410 | around 'connect_replicants' => sub { |
64cdad22 |
411 | my ($method, $self, @args) = @_; |
412 | $self->$method($self->schema, @args); |
955a6df6 |
413 | }; |
2bf79155 |
414 | |
2bf79155 |
415 | =head2 all_storages |
416 | |
417 | Returns an array of of all the connected storage backends. The first element |
418 | in the returned array is the master, and the remainings are each of the |
419 | replicants. |
420 | |
421 | =cut |
422 | |
423 | sub all_storages { |
64cdad22 |
424 | my $self = shift @_; |
425 | return grep {defined $_ && blessed $_} ( |
426 | $self->master, |
427 | $self->replicants, |
428 | ); |
2bf79155 |
429 | } |
430 | |
c4d3fae2 |
431 | =head2 execute_reliably ($coderef, ?@args) |
432 | |
433 | Given a coderef, saves the current state of the L</read_handler>, forces it to |
434 | use reliable storage (ie sets it to the master), executes a coderef and then |
435 | restores the original state. |
436 | |
437 | Example: |
438 | |
64cdad22 |
439 | my $reliably = sub { |
440 | my $name = shift @_; |
441 | $schema->resultset('User')->create({name=>$name}); |
442 | my $user_rs = $schema->resultset('User')->find({name=>$name}); |
443 | return $user_rs; |
444 | }; |
c4d3fae2 |
445 | |
64cdad22 |
446 | my $user_rs = $schema->storage->execute_reliably($reliably, 'John'); |
c4d3fae2 |
447 | |
448 | Use this when you must be certain of your database state, such as when you just |
449 | inserted something and need to get a resultset including it, etc. |
450 | |
451 | =cut |
452 | |
453 | sub execute_reliably { |
64cdad22 |
454 | my ($self, $coderef, @args) = @_; |
455 | |
456 | unless( ref $coderef eq 'CODE') { |
457 | $self->throw_exception('Second argument must be a coderef'); |
458 | } |
459 | |
460 | ##Get copy of master storage |
461 | my $master = $self->master; |
462 | |
463 | ##Get whatever the current read hander is |
464 | my $current = $self->read_handler; |
465 | |
466 | ##Set the read handler to master |
467 | $self->read_handler($master); |
468 | |
469 | ## do whatever the caller needs |
470 | my @result; |
471 | my $want_array = wantarray; |
472 | |
473 | eval { |
474 | if($want_array) { |
475 | @result = $coderef->(@args); |
476 | } elsif(defined $want_array) { |
477 | ($result[0]) = ($coderef->(@args)); |
ed213e85 |
478 | } else { |
64cdad22 |
479 | $coderef->(@args); |
480 | } |
481 | }; |
482 | |
483 | ##Reset to the original state |
484 | $self->read_handler($current); |
485 | |
486 | ##Exception testing has to come last, otherwise you might leave the |
487 | ##read_handler set to master. |
488 | |
489 | if($@) { |
490 | $self->throw_exception("coderef returned an error: $@"); |
491 | } else { |
492 | return $want_array ? @result : $result[0]; |
493 | } |
c4d3fae2 |
494 | } |
495 | |
cb6ec758 |
496 | =head2 set_reliable_storage |
497 | |
498 | Sets the current $schema to be 'reliable', that is all queries, both read and |
499 | write are sent to the master |
64cdad22 |
500 | |
cb6ec758 |
501 | =cut |
502 | |
503 | sub set_reliable_storage { |
64cdad22 |
504 | my $self = shift @_; |
505 | my $schema = $self->schema; |
506 | my $write_handler = $self->schema->storage->write_handler; |
507 | |
508 | $schema->storage->read_handler($write_handler); |
cb6ec758 |
509 | } |
510 | |
511 | =head2 set_balanced_storage |
512 | |
513 | Sets the current $schema to be use the </balancer> for all reads, while all |
514 | writea are sent to the master only |
64cdad22 |
515 | |
cb6ec758 |
516 | =cut |
517 | |
518 | sub set_balanced_storage { |
64cdad22 |
519 | my $self = shift @_; |
520 | my $schema = $self->schema; |
521 | my $write_handler = $self->schema->storage->balancer; |
522 | |
523 | $schema->storage->read_handler($write_handler); |
cb6ec758 |
524 | } |
2bf79155 |
525 | |
6834cc1d |
526 | =head2 around: txn_do ($coderef) |
c4d3fae2 |
527 | |
528 | Overload to the txn_do method, which is delegated to whatever the |
529 | L<write_handler> is set to. We overload this in order to wrap in inside a |
530 | L</execute_reliably> method. |
531 | |
532 | =cut |
533 | |
6834cc1d |
534 | around 'txn_do' => sub { |
64cdad22 |
535 | my($txn_do, $self, $coderef, @args) = @_; |
536 | $self->execute_reliably(sub {$self->$txn_do($coderef, @args)}); |
6834cc1d |
537 | }; |
c4d3fae2 |
538 | |
2bf79155 |
539 | =head2 connected |
540 | |
541 | Check that the master and at least one of the replicants is connected. |
542 | |
543 | =cut |
544 | |
545 | sub connected { |
64cdad22 |
546 | my $self = shift @_; |
547 | return |
548 | $self->master->connected && |
549 | $self->pool->connected_replicants; |
2bf79155 |
550 | } |
551 | |
2bf79155 |
552 | =head2 ensure_connected |
553 | |
554 | Make sure all the storages are connected. |
555 | |
556 | =cut |
557 | |
558 | sub ensure_connected { |
64cdad22 |
559 | my $self = shift @_; |
560 | foreach my $source ($self->all_storages) { |
561 | $source->ensure_connected(@_); |
562 | } |
2bf79155 |
563 | } |
564 | |
2bf79155 |
565 | =head2 limit_dialect |
566 | |
567 | Set the limit_dialect for all existing storages |
568 | |
569 | =cut |
570 | |
571 | sub limit_dialect { |
64cdad22 |
572 | my $self = shift @_; |
573 | foreach my $source ($self->all_storages) { |
574 | $source->limit_dialect(@_); |
575 | } |
3fbe08e3 |
576 | return $self->master->quote_char; |
2bf79155 |
577 | } |
578 | |
2bf79155 |
579 | =head2 quote_char |
580 | |
581 | Set the quote_char for all existing storages |
582 | |
583 | =cut |
584 | |
585 | sub quote_char { |
64cdad22 |
586 | my $self = shift @_; |
587 | foreach my $source ($self->all_storages) { |
588 | $source->quote_char(@_); |
589 | } |
3fbe08e3 |
590 | return $self->master->quote_char; |
2bf79155 |
591 | } |
592 | |
2bf79155 |
593 | =head2 name_sep |
594 | |
595 | Set the name_sep for all existing storages |
596 | |
597 | =cut |
598 | |
599 | sub name_sep { |
64cdad22 |
600 | my $self = shift @_; |
601 | foreach my $source ($self->all_storages) { |
602 | $source->name_sep(@_); |
603 | } |
3fbe08e3 |
604 | return $self->master->name_sep; |
2bf79155 |
605 | } |
606 | |
2bf79155 |
607 | =head2 set_schema |
608 | |
609 | Set the schema object for all existing storages |
610 | |
611 | =cut |
612 | |
613 | sub set_schema { |
64cdad22 |
614 | my $self = shift @_; |
615 | foreach my $source ($self->all_storages) { |
616 | $source->set_schema(@_); |
617 | } |
2bf79155 |
618 | } |
619 | |
2bf79155 |
620 | =head2 debug |
621 | |
622 | set a debug flag across all storages |
623 | |
624 | =cut |
625 | |
626 | sub debug { |
64cdad22 |
627 | my $self = shift @_; |
3fbe08e3 |
628 | if(@_) { |
629 | foreach my $source ($self->all_storages) { |
630 | $source->debug(@_); |
631 | } |
64cdad22 |
632 | } |
3fbe08e3 |
633 | return $self->master->debug; |
2bf79155 |
634 | } |
635 | |
2bf79155 |
636 | =head2 debugobj |
637 | |
638 | set a debug object across all storages |
639 | |
640 | =cut |
641 | |
642 | sub debugobj { |
64cdad22 |
643 | my $self = shift @_; |
3fbe08e3 |
644 | if(@_) { |
645 | foreach my $source ($self->all_storages) { |
646 | $source->debugobj(@_); |
647 | } |
64cdad22 |
648 | } |
3fbe08e3 |
649 | return $self->master->debugobj; |
2bf79155 |
650 | } |
651 | |
2bf79155 |
652 | =head2 debugfh |
653 | |
654 | set a debugfh object across all storages |
655 | |
656 | =cut |
657 | |
658 | sub debugfh { |
64cdad22 |
659 | my $self = shift @_; |
3fbe08e3 |
660 | if(@_) { |
661 | foreach my $source ($self->all_storages) { |
662 | $source->debugfh(@_); |
663 | } |
64cdad22 |
664 | } |
3fbe08e3 |
665 | return $self->master->debugfh; |
2bf79155 |
666 | } |
667 | |
2bf79155 |
668 | =head2 debugcb |
669 | |
670 | set a debug callback across all storages |
671 | |
672 | =cut |
673 | |
674 | sub debugcb { |
64cdad22 |
675 | my $self = shift @_; |
3fbe08e3 |
676 | if(@_) { |
677 | foreach my $source ($self->all_storages) { |
678 | $source->debugcb(@_); |
679 | } |
64cdad22 |
680 | } |
3fbe08e3 |
681 | return $self->master->debugcb; |
2bf79155 |
682 | } |
683 | |
2bf79155 |
684 | =head2 disconnect |
685 | |
686 | disconnect everything |
687 | |
688 | =cut |
689 | |
690 | sub disconnect { |
64cdad22 |
691 | my $self = shift @_; |
692 | foreach my $source ($self->all_storages) { |
693 | $source->disconnect(@_); |
694 | } |
2bf79155 |
695 | } |
696 | |
7e38d850 |
697 | =head1 GOTCHAS |
698 | |
699 | Due to the fact that replicants can lag behind a master, you must take care to |
700 | make sure you use one of the methods to force read queries to a master should |
701 | you need realtime data integrity. For example, if you insert a row, and then |
702 | immediately re-read it from the database (say, by doing $row->discard_changes) |
703 | or you insert a row and then immediately build a query that expects that row |
704 | to be an item, you should force the master to handle reads. Otherwise, due to |
705 | the lag, there is no certainty your data will be in the expected state. |
706 | |
707 | For data integrity, all transactions automatically use the master storage for |
708 | all read and write queries. Using a transaction is the preferred and recommended |
709 | method to force the master to handle all read queries. |
710 | |
711 | Otherwise, you can force a single query to use the master with the 'force_pool' |
712 | attribute: |
713 | |
714 | my $row = $resultset->search(undef, {force_pool=>'master'})->find($pk); |
715 | |
716 | This attribute will safely be ignore by non replicated storages, so you can use |
717 | the same code for both types of systems. |
718 | |
719 | Lastly, you can use the L</execute_reliably> method, which works very much like |
720 | a transaction. |
721 | |
722 | For debugging, you can turn replication on/off with the methods L</set_reliable_storage> |
723 | and L</set_balanced_storage>, however this operates at a global level and is not |
724 | suitable if you have a shared Schema object being used by multiple processes, |
725 | such as on a web application server. You can get around this limitation by |
726 | using the Schema clone method. |
727 | |
728 | my $new_schema = $schema->clone; |
729 | $new_schema->set_reliable_storage; |
730 | |
731 | ## $new_schema will use only the Master storage for all reads/writes while |
732 | ## the $schema object will use replicated storage. |
733 | |
f5d3a5de |
734 | =head1 AUTHOR |
735 | |
64cdad22 |
736 | John Napiorkowski <john.napiorkowski@takkle.com> |
f5d3a5de |
737 | |
c4d3fae2 |
738 | Based on code originated by: |
f5d3a5de |
739 | |
64cdad22 |
740 | Norbert Csongrádi <bert@cpan.org> |
741 | Peter Siklósi <einon@einon.hu> |
2156bbdd |
742 | |
f5d3a5de |
743 | =head1 LICENSE |
744 | |
745 | You may distribute this code under the same terms as Perl itself. |
746 | |
747 | =cut |
748 | |
c354902c |
749 | __PACKAGE__->meta->make_immutable; |
750 | |
f5d3a5de |
751 | 1; |