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