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2156bbdd |
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', |
b88b85e7 |
14 | Hash::Merge => '0.11' |
ecb65397 |
15 | ); |
16 | |
17 | my @didnt_load; |
18 | |
19 | for my $module (keys %replication_required) { |
20 | eval "use $module $replication_required{$module}"; |
21 | push @didnt_load, "$module $replication_required{$module}" |
22 | if $@; |
23 | } |
24 | |
25 | croak("@{[ join ', ', @didnt_load ]} are missing and are required for Replication") |
26 | if @didnt_load; |
27 | } |
28 | |
b2e4d522 |
29 | use Moose; |
26ab719a |
30 | use DBIx::Class::Storage::DBI; |
2bf79155 |
31 | use DBIx::Class::Storage::DBI::Replicated::Pool; |
26ab719a |
32 | use DBIx::Class::Storage::DBI::Replicated::Balancer; |
9901aad7 |
33 | use DBIx::Class::Storage::DBI::Replicated::Types 'BalancerClassNamePart'; |
41916570 |
34 | use MooseX::Types::Moose qw/ClassName HashRef Object/; |
b2e4d522 |
35 | use Scalar::Util 'reftype'; |
36 | use Carp::Clan qw/^DBIx::Class/; |
b88b85e7 |
37 | use Hash::Merge 'merge'; |
9901aad7 |
38 | |
39 | use namespace::clean -except => 'meta'; |
2bf79155 |
40 | |
41 | =head1 NAME |
42 | |
ecb65397 |
43 | DBIx::Class::Storage::DBI::Replicated - BETA Replicated database support |
2bf79155 |
44 | |
45 | =head1 SYNOPSIS |
46 | |
47 | The Following example shows how to change an existing $schema to a replicated |
48 | storage type, add some replicated (readonly) databases, and perform reporting |
955a6df6 |
49 | tasks. |
2bf79155 |
50 | |
64cdad22 |
51 | ## Change storage_type in your schema class |
52 | $schema->storage_type( ['::DBI::Replicated', {balancer=>'::Random'}] ); |
53 | |
54 | ## Add some slaves. Basically this is an array of arrayrefs, where each |
55 | ## arrayref is database connect information |
56 | |
57 | $schema->storage->connect_replicants( |
58 | [$dsn1, $user, $pass, \%opts], |
59 | [$dsn2, $user, $pass, \%opts], |
60 | [$dsn3, $user, $pass, \%opts], |
61 | ); |
62 | |
7e38d850 |
63 | ## Now, just use the $schema as normal |
64 | $schema->resultset('Source')->search({name=>'etc'}); |
65 | |
66 | ## You can force a given query to use a particular storage using the search |
67 | ### attribute 'force_pool'. For example: |
68 | |
69 | my $RS = $schema->resultset('Source')->search(undef, {force_pool=>'master'}); |
70 | |
71 | ## Now $RS will force everything (both reads and writes) to use whatever was |
72 | ## setup as the master storage. 'master' is hardcoded to always point to the |
73 | ## Master, but you can also use any Replicant name. Please see: |
74 | ## L<DBIx::Class::Storage::Replicated::Pool> and the replicants attribute for |
75 | ## More. Also see transactions and L</execute_reliably> for alternative ways |
76 | ## to force read traffic to the master. |
77 | |
2bf79155 |
78 | =head1 DESCRIPTION |
79 | |
7e38d850 |
80 | Warning: This class is marked BETA. This has been running a production |
ccb3b897 |
81 | website using MySQL native replication as its backend and we have some decent |
7e38d850 |
82 | test coverage but the code hasn't yet been stressed by a variety of databases. |
83 | Individual DB's may have quirks we are not aware of. Please use this in first |
84 | development and pass along your experiences/bug fixes. |
2bf79155 |
85 | |
86 | This class implements replicated data store for DBI. Currently you can define |
87 | one master and numerous slave database connections. All write-type queries |
88 | (INSERT, UPDATE, DELETE and even LAST_INSERT_ID) are routed to master |
89 | database, all read-type queries (SELECTs) go to the slave database. |
90 | |
91 | Basically, any method request that L<DBIx::Class::Storage::DBI> would normally |
bca099a3 |
92 | handle gets delegated to one of the two attributes: L</read_handler> or to |
93 | L</write_handler>. Additionally, some methods need to be distributed |
2bf79155 |
94 | to all existing storages. This way our storage class is a drop in replacement |
95 | for L<DBIx::Class::Storage::DBI>. |
96 | |
97 | Read traffic is spread across the replicants (slaves) occuring to a user |
98 | selected algorithm. The default algorithm is random weighted. |
99 | |
bca099a3 |
100 | =head1 NOTES |
101 | |
102 | The consistancy betweeen master and replicants is database specific. The Pool |
103 | gives you a method to validate it's replicants, removing and replacing them |
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104 | when they fail/pass predefined criteria. Please make careful use of the ways |
ecb65397 |
105 | to force a query to run against Master when needed. |
106 | |
107 | =head1 REQUIREMENTS |
108 | |
109 | Replicated Storage has additional requirements not currently part of L<DBIx::Class> |
110 | |
9901aad7 |
111 | Moose => 0.77 |
ecb65397 |
112 | MooseX::AttributeHelpers => 0.12 |
9901aad7 |
113 | MooseX::Types => 0.10 |
114 | namespace::clean => 0.11 |
b88b85e7 |
115 | Hash::Merge => 0.11 |
ecb65397 |
116 | |
117 | You will need to install these modules manually via CPAN or make them part of the |
118 | Makefile for your distribution. |
2bf79155 |
119 | |
120 | =head1 ATTRIBUTES |
121 | |
122 | This class defines the following attributes. |
123 | |
2ce6e9a6 |
124 | =head2 schema |
125 | |
126 | The underlying L<DBIx::Class::Schema> object this storage is attaching |
127 | |
128 | =cut |
129 | |
130 | has 'schema' => ( |
131 | is=>'rw', |
132 | isa=>'DBIx::Class::Schema', |
133 | weak_ref=>1, |
134 | required=>1, |
135 | ); |
136 | |
26ab719a |
137 | =head2 pool_type |
2bf79155 |
138 | |
26ab719a |
139 | Contains the classname which will instantiate the L</pool> object. Defaults |
140 | to: L<DBIx::Class::Storage::DBI::Replicated::Pool>. |
2bf79155 |
141 | |
142 | =cut |
143 | |
26ab719a |
144 | has 'pool_type' => ( |
dcdf7b2c |
145 | is=>'rw', |
41916570 |
146 | isa=>ClassName, |
2ce6e9a6 |
147 | default=>'DBIx::Class::Storage::DBI::Replicated::Pool', |
64cdad22 |
148 | handles=>{ |
149 | 'create_pool' => 'new', |
150 | }, |
2bf79155 |
151 | ); |
152 | |
f068a139 |
153 | =head2 pool_args |
154 | |
155 | Contains a hashref of initialized information to pass to the Balancer object. |
156 | See L<DBIx::Class::Storage::Replicated::Pool> for available arguments. |
157 | |
158 | =cut |
159 | |
160 | has 'pool_args' => ( |
dcdf7b2c |
161 | is=>'rw', |
41916570 |
162 | isa=>HashRef, |
64cdad22 |
163 | lazy=>1, |
64cdad22 |
164 | default=>sub { {} }, |
f068a139 |
165 | ); |
166 | |
167 | |
26ab719a |
168 | =head2 balancer_type |
2bf79155 |
169 | |
170 | The replication pool requires a balance class to provider the methods for |
171 | choose how to spread the query load across each replicant in the pool. |
172 | |
173 | =cut |
174 | |
26ab719a |
175 | has 'balancer_type' => ( |
dcdf7b2c |
176 | is=>'rw', |
9901aad7 |
177 | isa=>BalancerClassNamePart, |
2ce6e9a6 |
178 | coerce=>1, |
179 | required=>1, |
180 | default=> 'DBIx::Class::Storage::DBI::Replicated::Balancer::First', |
64cdad22 |
181 | handles=>{ |
182 | 'create_balancer' => 'new', |
183 | }, |
2bf79155 |
184 | ); |
185 | |
17b05c13 |
186 | =head2 balancer_args |
187 | |
188 | Contains a hashref of initialized information to pass to the Balancer object. |
f068a139 |
189 | See L<DBIx::Class::Storage::Replicated::Balancer> for available arguments. |
17b05c13 |
190 | |
191 | =cut |
192 | |
193 | has 'balancer_args' => ( |
dcdf7b2c |
194 | is=>'rw', |
41916570 |
195 | isa=>HashRef, |
64cdad22 |
196 | lazy=>1, |
197 | required=>1, |
198 | default=>sub { {} }, |
17b05c13 |
199 | ); |
200 | |
26ab719a |
201 | =head2 pool |
2bf79155 |
202 | |
26ab719a |
203 | Is a <DBIx::Class::Storage::DBI::Replicated::Pool> or derived class. This is a |
204 | container class for one or more replicated databases. |
2bf79155 |
205 | |
206 | =cut |
207 | |
26ab719a |
208 | has 'pool' => ( |
64cdad22 |
209 | is=>'ro', |
210 | isa=>'DBIx::Class::Storage::DBI::Replicated::Pool', |
211 | lazy_build=>1, |
212 | handles=>[qw/ |
213 | connect_replicants |
214 | replicants |
215 | has_replicants |
216 | /], |
2bf79155 |
217 | ); |
218 | |
26ab719a |
219 | =head2 balancer |
2bf79155 |
220 | |
26ab719a |
221 | Is a <DBIx::Class::Storage::DBI::Replicated::Balancer> or derived class. This |
222 | is a class that takes a pool (<DBIx::Class::Storage::DBI::Replicated::Pool>) |
2bf79155 |
223 | |
26ab719a |
224 | =cut |
2bf79155 |
225 | |
26ab719a |
226 | has 'balancer' => ( |
dcdf7b2c |
227 | is=>'rw', |
64cdad22 |
228 | isa=>'DBIx::Class::Storage::DBI::Replicated::Balancer', |
229 | lazy_build=>1, |
230 | handles=>[qw/auto_validate_every/], |
26ab719a |
231 | ); |
2bf79155 |
232 | |
cb6ec758 |
233 | =head2 master |
234 | |
235 | The master defines the canonical state for a pool of connected databases. All |
236 | the replicants are expected to match this databases state. Thus, in a classic |
237 | Master / Slaves distributed system, all the slaves are expected to replicate |
238 | the Master's state as quick as possible. This is the only database in the |
239 | pool of databases that is allowed to handle write traffic. |
240 | |
241 | =cut |
242 | |
243 | has 'master' => ( |
64cdad22 |
244 | is=> 'ro', |
245 | isa=>'DBIx::Class::Storage::DBI', |
246 | lazy_build=>1, |
cb6ec758 |
247 | ); |
248 | |
cb6ec758 |
249 | =head1 ATTRIBUTES IMPLEMENTING THE DBIx::Storage::DBI INTERFACE |
250 | |
251 | The following methods are delegated all the methods required for the |
252 | L<DBIx::Class::Storage::DBI> interface. |
253 | |
254 | =head2 read_handler |
255 | |
256 | Defines an object that implements the read side of L<BIx::Class::Storage::DBI>. |
257 | |
258 | =cut |
259 | |
260 | has 'read_handler' => ( |
64cdad22 |
261 | is=>'rw', |
41916570 |
262 | isa=>Object, |
64cdad22 |
263 | lazy_build=>1, |
264 | handles=>[qw/ |
265 | select |
266 | select_single |
267 | columns_info_for |
268 | /], |
cb6ec758 |
269 | ); |
270 | |
cb6ec758 |
271 | =head2 write_handler |
272 | |
273 | Defines an object that implements the write side of L<BIx::Class::Storage::DBI>. |
274 | |
275 | =cut |
276 | |
277 | has 'write_handler' => ( |
64cdad22 |
278 | is=>'ro', |
41916570 |
279 | isa=>Object, |
64cdad22 |
280 | lazy_build=>1, |
64cdad22 |
281 | handles=>[qw/ |
282 | on_connect_do |
283 | on_disconnect_do |
284 | connect_info |
285 | throw_exception |
286 | sql_maker |
287 | sqlt_type |
288 | create_ddl_dir |
289 | deployment_statements |
290 | datetime_parser |
291 | datetime_parser_type |
292 | last_insert_id |
293 | insert |
294 | insert_bulk |
295 | update |
296 | delete |
297 | dbh |
2ce6e9a6 |
298 | txn_begin |
64cdad22 |
299 | txn_do |
300 | txn_commit |
301 | txn_rollback |
2ce6e9a6 |
302 | txn_scope_guard |
64cdad22 |
303 | sth |
304 | deploy |
0180bef9 |
305 | with_deferred_fk_checks |
2ce6e9a6 |
306 | |
64cdad22 |
307 | reload_row |
2ce6e9a6 |
308 | _prep_for_execute |
2ce6e9a6 |
309 | |
64cdad22 |
310 | /], |
cb6ec758 |
311 | ); |
312 | |
b2e4d522 |
313 | has _master_connect_info_opts => |
314 | (is => 'rw', isa => HashRef, default => sub { {} }); |
315 | |
316 | =head2 around: connect_info |
317 | |
318 | Preserve master's C<connect_info> options (for merging with replicants.) |
dcdf7b2c |
319 | Also set any Replicated related options from connect_info, such as |
320 | C<pool_type>, C<pool_args>, C<balancer_type> and C<balancer_args>. |
b2e4d522 |
321 | |
322 | =cut |
323 | |
324 | around connect_info => sub { |
325 | my ($next, $self, $info, @extra) = @_; |
326 | |
327 | my %opts; |
328 | for my $arg (@$info) { |
329 | next unless (reftype($arg)||'') eq 'HASH'; |
b88b85e7 |
330 | %opts = %{ merge($arg, \%opts) }; |
b2e4d522 |
331 | } |
b2e4d522 |
332 | delete $opts{dsn}; |
333 | |
dcdf7b2c |
334 | if (@opts{qw/pool_type pool_args/}) { |
335 | $self->pool_type(delete $opts{pool_type}) |
336 | if $opts{pool_type}; |
337 | |
b88b85e7 |
338 | $self->pool_args( |
339 | merge((delete $opts{pool_args} || {}), $self->pool_args) |
340 | ); |
dcdf7b2c |
341 | |
67c43863 |
342 | $self->pool($self->_build_pool) |
343 | if $self->pool; |
dcdf7b2c |
344 | } |
345 | |
346 | if (@opts{qw/balancer_type balancer_args/}) { |
347 | $self->balancer_type(delete $opts{balancer_type}) |
348 | if $opts{balancer_type}; |
349 | |
b88b85e7 |
350 | $self->balancer_args( |
351 | merge((delete $opts{balancer_args} || {}), $self->balancer_args) |
352 | ); |
dcdf7b2c |
353 | |
67c43863 |
354 | $self->balancer($self->_build_balancer) |
355 | if $self->balancer; |
dcdf7b2c |
356 | } |
357 | |
b2e4d522 |
358 | $self->_master_connect_info_opts(\%opts); |
359 | |
360 | $self->$next($info, @extra); |
361 | }; |
362 | |
26ab719a |
363 | =head1 METHODS |
2bf79155 |
364 | |
26ab719a |
365 | This class defines the following methods. |
2bf79155 |
366 | |
c354902c |
367 | =head2 BUILDARGS |
2bf79155 |
368 | |
cb6ec758 |
369 | L<DBIx::Class::Schema> when instantiating it's storage passed itself as the |
2ce6e9a6 |
370 | first argument. So we need to massage the arguments a bit so that all the |
371 | bits get put into the correct places. |
2bf79155 |
372 | |
373 | =cut |
374 | |
c354902c |
375 | sub BUILDARGS { |
376 | my ($class, $schema, $storage_type_args, @args) = @_; |
377 | |
378 | return { |
379 | schema=>$schema, |
380 | %$storage_type_args, |
381 | @args |
382 | } |
383 | } |
2bf79155 |
384 | |
cb6ec758 |
385 | =head2 _build_master |
2bf79155 |
386 | |
cb6ec758 |
387 | Lazy builder for the L</master> attribute. |
2bf79155 |
388 | |
389 | =cut |
390 | |
cb6ec758 |
391 | sub _build_master { |
2ce6e9a6 |
392 | my $self = shift @_; |
ee356d00 |
393 | my $master = DBIx::Class::Storage::DBI->new($self->schema); |
394 | DBIx::Class::Storage::DBI::Replicated::WithDSN->meta->apply($master); |
395 | $master |
106d5f3b |
396 | } |
397 | |
26ab719a |
398 | =head2 _build_pool |
2bf79155 |
399 | |
26ab719a |
400 | Lazy builder for the L</pool> attribute. |
2bf79155 |
401 | |
402 | =cut |
403 | |
26ab719a |
404 | sub _build_pool { |
64cdad22 |
405 | my $self = shift @_; |
406 | $self->create_pool(%{$self->pool_args}); |
2bf79155 |
407 | } |
408 | |
26ab719a |
409 | =head2 _build_balancer |
2bf79155 |
410 | |
cb6ec758 |
411 | Lazy builder for the L</balancer> attribute. This takes a Pool object so that |
412 | the balancer knows which pool it's balancing. |
2bf79155 |
413 | |
414 | =cut |
415 | |
26ab719a |
416 | sub _build_balancer { |
64cdad22 |
417 | my $self = shift @_; |
418 | $self->create_balancer( |
419 | pool=>$self->pool, |
420 | master=>$self->master, |
421 | %{$self->balancer_args}, |
422 | ); |
2bf79155 |
423 | } |
424 | |
cb6ec758 |
425 | =head2 _build_write_handler |
2bf79155 |
426 | |
cb6ec758 |
427 | Lazy builder for the L</write_handler> attribute. The default is to set this to |
428 | the L</master>. |
50336325 |
429 | |
430 | =cut |
431 | |
cb6ec758 |
432 | sub _build_write_handler { |
64cdad22 |
433 | return shift->master; |
cb6ec758 |
434 | } |
50336325 |
435 | |
cb6ec758 |
436 | =head2 _build_read_handler |
2bf79155 |
437 | |
cb6ec758 |
438 | Lazy builder for the L</read_handler> attribute. The default is to set this to |
439 | the L</balancer>. |
2bf79155 |
440 | |
441 | =cut |
442 | |
cb6ec758 |
443 | sub _build_read_handler { |
64cdad22 |
444 | return shift->balancer; |
cb6ec758 |
445 | } |
50336325 |
446 | |
cb6ec758 |
447 | =head2 around: connect_replicants |
2bf79155 |
448 | |
cb6ec758 |
449 | All calls to connect_replicants needs to have an existing $schema tacked onto |
b2e4d522 |
450 | top of the args, since L<DBIx::Storage::DBI> needs it, and any C<connect_info> |
451 | options merged with the master, with replicant opts having higher priority. |
955a6df6 |
452 | |
cb6ec758 |
453 | =cut |
955a6df6 |
454 | |
b2e4d522 |
455 | around connect_replicants => sub { |
456 | my ($next, $self, @args) = @_; |
457 | |
458 | for my $r (@args) { |
459 | $r = [ $r ] unless reftype $r eq 'ARRAY'; |
460 | |
461 | croak "coderef replicant connect_info not supported" |
462 | if ref $r->[0] && reftype $r->[0] eq 'CODE'; |
463 | |
464 | # any connect_info options? |
465 | my $i = 0; |
466 | $i++ while $i < @$r && (reftype($r->[$i])||'') ne 'HASH'; |
467 | |
468 | # make one if none |
469 | $r->[$i] = {} unless $r->[$i]; |
470 | |
471 | # merge if two hashes |
b88b85e7 |
472 | my @hashes = @$r[$i .. $#{$r}]; |
473 | |
474 | croak "invalid connect_info options" |
475 | if (grep { reftype($_) eq 'HASH' } @hashes) != @hashes; |
476 | |
477 | croak "too many hashrefs in connect_info" |
478 | if @hashes > 2; |
479 | |
480 | my %opts = %{ merge(reverse @hashes) }; |
481 | |
482 | # delete them |
b2e4d522 |
483 | splice @$r, $i+1, ($#{$r} - $i), (); |
484 | |
485 | # merge with master |
b88b85e7 |
486 | %opts = %{ merge(\%opts, $self->_master_connect_info_opts) }; |
b2e4d522 |
487 | |
488 | # update |
489 | $r->[$i] = \%opts; |
490 | } |
491 | |
492 | $self->$next($self->schema, @args); |
955a6df6 |
493 | }; |
2bf79155 |
494 | |
2bf79155 |
495 | =head2 all_storages |
496 | |
497 | Returns an array of of all the connected storage backends. The first element |
498 | in the returned array is the master, and the remainings are each of the |
499 | replicants. |
500 | |
501 | =cut |
502 | |
503 | sub all_storages { |
64cdad22 |
504 | my $self = shift @_; |
505 | return grep {defined $_ && blessed $_} ( |
506 | $self->master, |
6412a592 |
507 | values %{ $self->replicants }, |
64cdad22 |
508 | ); |
2bf79155 |
509 | } |
510 | |
c4d3fae2 |
511 | =head2 execute_reliably ($coderef, ?@args) |
512 | |
513 | Given a coderef, saves the current state of the L</read_handler>, forces it to |
514 | use reliable storage (ie sets it to the master), executes a coderef and then |
515 | restores the original state. |
516 | |
517 | Example: |
518 | |
64cdad22 |
519 | my $reliably = sub { |
520 | my $name = shift @_; |
521 | $schema->resultset('User')->create({name=>$name}); |
522 | my $user_rs = $schema->resultset('User')->find({name=>$name}); |
523 | return $user_rs; |
524 | }; |
c4d3fae2 |
525 | |
64cdad22 |
526 | my $user_rs = $schema->storage->execute_reliably($reliably, 'John'); |
c4d3fae2 |
527 | |
528 | Use this when you must be certain of your database state, such as when you just |
529 | inserted something and need to get a resultset including it, etc. |
530 | |
531 | =cut |
532 | |
533 | sub execute_reliably { |
64cdad22 |
534 | my ($self, $coderef, @args) = @_; |
535 | |
536 | unless( ref $coderef eq 'CODE') { |
537 | $self->throw_exception('Second argument must be a coderef'); |
538 | } |
539 | |
540 | ##Get copy of master storage |
541 | my $master = $self->master; |
542 | |
543 | ##Get whatever the current read hander is |
544 | my $current = $self->read_handler; |
545 | |
546 | ##Set the read handler to master |
547 | $self->read_handler($master); |
548 | |
549 | ## do whatever the caller needs |
550 | my @result; |
551 | my $want_array = wantarray; |
552 | |
553 | eval { |
554 | if($want_array) { |
555 | @result = $coderef->(@args); |
556 | } elsif(defined $want_array) { |
557 | ($result[0]) = ($coderef->(@args)); |
ed213e85 |
558 | } else { |
64cdad22 |
559 | $coderef->(@args); |
560 | } |
561 | }; |
562 | |
563 | ##Reset to the original state |
564 | $self->read_handler($current); |
565 | |
566 | ##Exception testing has to come last, otherwise you might leave the |
567 | ##read_handler set to master. |
568 | |
569 | if($@) { |
570 | $self->throw_exception("coderef returned an error: $@"); |
571 | } else { |
572 | return $want_array ? @result : $result[0]; |
573 | } |
c4d3fae2 |
574 | } |
575 | |
cb6ec758 |
576 | =head2 set_reliable_storage |
577 | |
578 | Sets the current $schema to be 'reliable', that is all queries, both read and |
579 | write are sent to the master |
64cdad22 |
580 | |
cb6ec758 |
581 | =cut |
582 | |
583 | sub set_reliable_storage { |
64cdad22 |
584 | my $self = shift @_; |
585 | my $schema = $self->schema; |
586 | my $write_handler = $self->schema->storage->write_handler; |
587 | |
588 | $schema->storage->read_handler($write_handler); |
cb6ec758 |
589 | } |
590 | |
591 | =head2 set_balanced_storage |
592 | |
593 | Sets the current $schema to be use the </balancer> for all reads, while all |
594 | writea are sent to the master only |
64cdad22 |
595 | |
cb6ec758 |
596 | =cut |
597 | |
598 | sub set_balanced_storage { |
64cdad22 |
599 | my $self = shift @_; |
600 | my $schema = $self->schema; |
601 | my $write_handler = $self->schema->storage->balancer; |
602 | |
603 | $schema->storage->read_handler($write_handler); |
cb6ec758 |
604 | } |
2bf79155 |
605 | |
6834cc1d |
606 | =head2 around: txn_do ($coderef) |
c4d3fae2 |
607 | |
608 | Overload to the txn_do method, which is delegated to whatever the |
609 | L<write_handler> is set to. We overload this in order to wrap in inside a |
610 | L</execute_reliably> method. |
611 | |
612 | =cut |
613 | |
6834cc1d |
614 | around 'txn_do' => sub { |
64cdad22 |
615 | my($txn_do, $self, $coderef, @args) = @_; |
616 | $self->execute_reliably(sub {$self->$txn_do($coderef, @args)}); |
6834cc1d |
617 | }; |
c4d3fae2 |
618 | |
2bf79155 |
619 | =head2 connected |
620 | |
621 | Check that the master and at least one of the replicants is connected. |
622 | |
623 | =cut |
624 | |
625 | sub connected { |
64cdad22 |
626 | my $self = shift @_; |
627 | return |
628 | $self->master->connected && |
629 | $self->pool->connected_replicants; |
2bf79155 |
630 | } |
631 | |
2bf79155 |
632 | =head2 ensure_connected |
633 | |
634 | Make sure all the storages are connected. |
635 | |
636 | =cut |
637 | |
638 | sub ensure_connected { |
64cdad22 |
639 | my $self = shift @_; |
640 | foreach my $source ($self->all_storages) { |
641 | $source->ensure_connected(@_); |
642 | } |
2bf79155 |
643 | } |
644 | |
2bf79155 |
645 | =head2 limit_dialect |
646 | |
647 | Set the limit_dialect for all existing storages |
648 | |
649 | =cut |
650 | |
651 | sub limit_dialect { |
64cdad22 |
652 | my $self = shift @_; |
653 | foreach my $source ($self->all_storages) { |
654 | $source->limit_dialect(@_); |
655 | } |
3fbe08e3 |
656 | return $self->master->quote_char; |
2bf79155 |
657 | } |
658 | |
2bf79155 |
659 | =head2 quote_char |
660 | |
661 | Set the quote_char for all existing storages |
662 | |
663 | =cut |
664 | |
665 | sub quote_char { |
64cdad22 |
666 | my $self = shift @_; |
667 | foreach my $source ($self->all_storages) { |
668 | $source->quote_char(@_); |
669 | } |
3fbe08e3 |
670 | return $self->master->quote_char; |
2bf79155 |
671 | } |
672 | |
2bf79155 |
673 | =head2 name_sep |
674 | |
675 | Set the name_sep for all existing storages |
676 | |
677 | =cut |
678 | |
679 | sub name_sep { |
64cdad22 |
680 | my $self = shift @_; |
681 | foreach my $source ($self->all_storages) { |
682 | $source->name_sep(@_); |
683 | } |
3fbe08e3 |
684 | return $self->master->name_sep; |
2bf79155 |
685 | } |
686 | |
2bf79155 |
687 | =head2 set_schema |
688 | |
689 | Set the schema object for all existing storages |
690 | |
691 | =cut |
692 | |
693 | sub set_schema { |
64cdad22 |
694 | my $self = shift @_; |
695 | foreach my $source ($self->all_storages) { |
696 | $source->set_schema(@_); |
697 | } |
2bf79155 |
698 | } |
699 | |
2bf79155 |
700 | =head2 debug |
701 | |
702 | set a debug flag across all storages |
703 | |
704 | =cut |
705 | |
706 | sub debug { |
64cdad22 |
707 | my $self = shift @_; |
3fbe08e3 |
708 | if(@_) { |
709 | foreach my $source ($self->all_storages) { |
710 | $source->debug(@_); |
711 | } |
64cdad22 |
712 | } |
3fbe08e3 |
713 | return $self->master->debug; |
2bf79155 |
714 | } |
715 | |
2bf79155 |
716 | =head2 debugobj |
717 | |
718 | set a debug object across all storages |
719 | |
720 | =cut |
721 | |
722 | sub debugobj { |
64cdad22 |
723 | my $self = shift @_; |
3fbe08e3 |
724 | if(@_) { |
725 | foreach my $source ($self->all_storages) { |
726 | $source->debugobj(@_); |
727 | } |
64cdad22 |
728 | } |
3fbe08e3 |
729 | return $self->master->debugobj; |
2bf79155 |
730 | } |
731 | |
2bf79155 |
732 | =head2 debugfh |
733 | |
734 | set a debugfh object across all storages |
735 | |
736 | =cut |
737 | |
738 | sub debugfh { |
64cdad22 |
739 | my $self = shift @_; |
3fbe08e3 |
740 | if(@_) { |
741 | foreach my $source ($self->all_storages) { |
742 | $source->debugfh(@_); |
743 | } |
64cdad22 |
744 | } |
3fbe08e3 |
745 | return $self->master->debugfh; |
2bf79155 |
746 | } |
747 | |
2bf79155 |
748 | =head2 debugcb |
749 | |
750 | set a debug callback across all storages |
751 | |
752 | =cut |
753 | |
754 | sub debugcb { |
64cdad22 |
755 | my $self = shift @_; |
3fbe08e3 |
756 | if(@_) { |
757 | foreach my $source ($self->all_storages) { |
758 | $source->debugcb(@_); |
759 | } |
64cdad22 |
760 | } |
3fbe08e3 |
761 | return $self->master->debugcb; |
2bf79155 |
762 | } |
763 | |
2bf79155 |
764 | =head2 disconnect |
765 | |
766 | disconnect everything |
767 | |
768 | =cut |
769 | |
770 | sub disconnect { |
64cdad22 |
771 | my $self = shift @_; |
772 | foreach my $source ($self->all_storages) { |
773 | $source->disconnect(@_); |
774 | } |
2bf79155 |
775 | } |
776 | |
b2e4d522 |
777 | =head2 cursor_class |
778 | |
779 | set cursor class on all storages, or return master's |
780 | |
781 | =cut |
782 | |
783 | sub cursor_class { |
784 | my ($self, $cursor_class) = @_; |
785 | |
786 | if ($cursor_class) { |
787 | $_->cursor_class($cursor_class) for $self->all_storages; |
788 | } |
789 | $self->master->cursor_class; |
790 | } |
791 | |
7e38d850 |
792 | =head1 GOTCHAS |
793 | |
794 | Due to the fact that replicants can lag behind a master, you must take care to |
795 | make sure you use one of the methods to force read queries to a master should |
796 | you need realtime data integrity. For example, if you insert a row, and then |
797 | immediately re-read it from the database (say, by doing $row->discard_changes) |
798 | or you insert a row and then immediately build a query that expects that row |
799 | to be an item, you should force the master to handle reads. Otherwise, due to |
800 | the lag, there is no certainty your data will be in the expected state. |
801 | |
802 | For data integrity, all transactions automatically use the master storage for |
803 | all read and write queries. Using a transaction is the preferred and recommended |
804 | method to force the master to handle all read queries. |
805 | |
806 | Otherwise, you can force a single query to use the master with the 'force_pool' |
807 | attribute: |
808 | |
809 | my $row = $resultset->search(undef, {force_pool=>'master'})->find($pk); |
810 | |
811 | This attribute will safely be ignore by non replicated storages, so you can use |
812 | the same code for both types of systems. |
813 | |
814 | Lastly, you can use the L</execute_reliably> method, which works very much like |
815 | a transaction. |
816 | |
817 | For debugging, you can turn replication on/off with the methods L</set_reliable_storage> |
818 | and L</set_balanced_storage>, however this operates at a global level and is not |
819 | suitable if you have a shared Schema object being used by multiple processes, |
820 | such as on a web application server. You can get around this limitation by |
821 | using the Schema clone method. |
822 | |
823 | my $new_schema = $schema->clone; |
824 | $new_schema->set_reliable_storage; |
825 | |
826 | ## $new_schema will use only the Master storage for all reads/writes while |
827 | ## the $schema object will use replicated storage. |
828 | |
f5d3a5de |
829 | =head1 AUTHOR |
830 | |
64cdad22 |
831 | John Napiorkowski <john.napiorkowski@takkle.com> |
f5d3a5de |
832 | |
c4d3fae2 |
833 | Based on code originated by: |
f5d3a5de |
834 | |
64cdad22 |
835 | Norbert Csongrádi <bert@cpan.org> |
836 | Peter Siklósi <einon@einon.hu> |
2156bbdd |
837 | |
f5d3a5de |
838 | =head1 LICENSE |
839 | |
840 | You may distribute this code under the same terms as Perl itself. |
841 | |
842 | =cut |
843 | |
c354902c |
844 | __PACKAGE__->meta->make_immutable; |
845 | |
f5d3a5de |
846 | 1; |