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1 | package DBIx::Class::Storage::DBI::Replicated; |
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2 | |
ecb65397 |
3 | BEGIN { |
4 | use Carp::Clan qw/^DBIx::Class/; |
a34b0c89 |
5 | use DBIx::Class; |
6 | croak('The following modules are required for Replication ' . DBIx::Class::Optional::Dependencies->req_missing_for ('replicated') ) |
7 | unless DBIx::Class::Optional::Dependencies->req_ok_for ('replicated'); |
ecb65397 |
8 | } |
9 | |
b2e4d522 |
10 | use Moose; |
26ab719a |
11 | use DBIx::Class::Storage::DBI; |
2bf79155 |
12 | use DBIx::Class::Storage::DBI::Replicated::Pool; |
26ab719a |
13 | use DBIx::Class::Storage::DBI::Replicated::Balancer; |
6a151f58 |
14 | use DBIx::Class::Storage::DBI::Replicated::Types qw/BalancerClassNamePart DBICSchema DBICStorageDBI/; |
41916570 |
15 | use MooseX::Types::Moose qw/ClassName HashRef Object/; |
b2e4d522 |
16 | use Scalar::Util 'reftype'; |
e666c5fd |
17 | use Hash::Merge; |
7da56142 |
18 | use List::Util qw/min max reduce/; |
ed7ab0f4 |
19 | use Try::Tiny; |
9901aad7 |
20 | |
21 | use namespace::clean -except => 'meta'; |
2bf79155 |
22 | |
23 | =head1 NAME |
24 | |
ecb65397 |
25 | DBIx::Class::Storage::DBI::Replicated - BETA Replicated database support |
2bf79155 |
26 | |
27 | =head1 SYNOPSIS |
28 | |
29 | The Following example shows how to change an existing $schema to a replicated |
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30 | storage type, add some replicated (read-only) databases, and perform reporting |
955a6df6 |
31 | tasks. |
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32 | |
3da4f736 |
33 | You should set the 'storage_type attribute to a replicated type. You should |
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34 | also define your arguments, such as which balancer you want and any arguments |
3da4f736 |
35 | that the Pool object should get. |
36 | |
ce854fd3 |
37 | my $schema = Schema::Class->clone; |
64cdad22 |
38 | $schema->storage_type( ['::DBI::Replicated', {balancer=>'::Random'}] ); |
ce854fd3 |
39 | $schema->connection(...); |
d4daee7b |
40 | |
3da4f736 |
41 | Next, you need to add in the Replicants. Basically this is an array of |
42 | arrayrefs, where each arrayref is database connect information. Think of these |
43 | arguments as what you'd pass to the 'normal' $schema->connect method. |
d4daee7b |
44 | |
64cdad22 |
45 | $schema->storage->connect_replicants( |
46 | [$dsn1, $user, $pass, \%opts], |
47 | [$dsn2, $user, $pass, \%opts], |
48 | [$dsn3, $user, $pass, \%opts], |
49 | ); |
d4daee7b |
50 | |
3da4f736 |
51 | Now, just use the $schema as you normally would. Automatically all reads will |
52 | be delegated to the replicants, while writes to the master. |
53 | |
7e38d850 |
54 | $schema->resultset('Source')->search({name=>'etc'}); |
d4daee7b |
55 | |
3da4f736 |
56 | You can force a given query to use a particular storage using the search |
57 | attribute 'force_pool'. For example: |
d4daee7b |
58 | |
7e38d850 |
59 | my $RS = $schema->resultset('Source')->search(undef, {force_pool=>'master'}); |
3da4f736 |
60 | |
61 | Now $RS will force everything (both reads and writes) to use whatever was setup |
62 | as the master storage. 'master' is hardcoded to always point to the Master, |
63 | but you can also use any Replicant name. Please see: |
212cc5c2 |
64 | L<DBIx::Class::Storage::DBI::Replicated::Pool> and the replicants attribute for more. |
3da4f736 |
65 | |
66 | Also see transactions and L</execute_reliably> for alternative ways to |
67 | force read traffic to the master. In general, you should wrap your statements |
68 | in a transaction when you are reading and writing to the same tables at the |
69 | same time, since your replicants will often lag a bit behind the master. |
212cc5c2 |
70 | |
71 | See L<DBIx::Class::Storage::DBI::Replicated::Instructions> for more help and |
72 | walkthroughs. |
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73 | |
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74 | =head1 DESCRIPTION |
75 | |
7e38d850 |
76 | Warning: This class is marked BETA. This has been running a production |
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77 | website using MySQL native replication as its backend and we have some decent |
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78 | test coverage but the code hasn't yet been stressed by a variety of databases. |
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79 | Individual DBs may have quirks we are not aware of. Please use this in first |
7e38d850 |
80 | development and pass along your experiences/bug fixes. |
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81 | |
82 | This class implements replicated data store for DBI. Currently you can define |
83 | one master and numerous slave database connections. All write-type queries |
84 | (INSERT, UPDATE, DELETE and even LAST_INSERT_ID) are routed to master |
85 | database, all read-type queries (SELECTs) go to the slave database. |
86 | |
87 | Basically, any method request that L<DBIx::Class::Storage::DBI> would normally |
bca099a3 |
88 | handle gets delegated to one of the two attributes: L</read_handler> or to |
89 | L</write_handler>. Additionally, some methods need to be distributed |
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90 | to all existing storages. This way our storage class is a drop in replacement |
91 | for L<DBIx::Class::Storage::DBI>. |
92 | |
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93 | Read traffic is spread across the replicants (slaves) occurring to a user |
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94 | selected algorithm. The default algorithm is random weighted. |
95 | |
bca099a3 |
96 | =head1 NOTES |
97 | |
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98 | The consistency between master and replicants is database specific. The Pool |
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99 | gives you a method to validate its replicants, removing and replacing them |
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100 | when they fail/pass predefined criteria. Please make careful use of the ways |
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101 | to force a query to run against Master when needed. |
102 | |
103 | =head1 REQUIREMENTS |
104 | |
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105 | Replicated Storage has additional requirements not currently part of |
aa8b2277 |
106 | L<DBIx::Class>. See L<DBIx::Class::Optional::Dependencies> for more details. |
2bf79155 |
107 | |
108 | =head1 ATTRIBUTES |
109 | |
110 | This class defines the following attributes. |
111 | |
2ce6e9a6 |
112 | =head2 schema |
113 | |
114 | The underlying L<DBIx::Class::Schema> object this storage is attaching |
115 | |
116 | =cut |
117 | |
118 | has 'schema' => ( |
119 | is=>'rw', |
6a151f58 |
120 | isa=>DBICSchema, |
2ce6e9a6 |
121 | weak_ref=>1, |
122 | required=>1, |
123 | ); |
124 | |
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125 | =head2 pool_type |
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126 | |
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127 | Contains the classname which will instantiate the L</pool> object. Defaults |
128 | to: L<DBIx::Class::Storage::DBI::Replicated::Pool>. |
2bf79155 |
129 | |
130 | =cut |
131 | |
26ab719a |
132 | has 'pool_type' => ( |
dcdf7b2c |
133 | is=>'rw', |
41916570 |
134 | isa=>ClassName, |
2ce6e9a6 |
135 | default=>'DBIx::Class::Storage::DBI::Replicated::Pool', |
64cdad22 |
136 | handles=>{ |
137 | 'create_pool' => 'new', |
138 | }, |
2bf79155 |
139 | ); |
140 | |
f068a139 |
141 | =head2 pool_args |
142 | |
143 | Contains a hashref of initialized information to pass to the Balancer object. |
212cc5c2 |
144 | See L<DBIx::Class::Storage::DBI::Replicated::Pool> for available arguments. |
f068a139 |
145 | |
146 | =cut |
147 | |
148 | has 'pool_args' => ( |
dcdf7b2c |
149 | is=>'rw', |
41916570 |
150 | isa=>HashRef, |
64cdad22 |
151 | lazy=>1, |
64cdad22 |
152 | default=>sub { {} }, |
f068a139 |
153 | ); |
154 | |
155 | |
26ab719a |
156 | =head2 balancer_type |
2bf79155 |
157 | |
158 | The replication pool requires a balance class to provider the methods for |
159 | choose how to spread the query load across each replicant in the pool. |
160 | |
161 | =cut |
162 | |
26ab719a |
163 | has 'balancer_type' => ( |
dcdf7b2c |
164 | is=>'rw', |
9901aad7 |
165 | isa=>BalancerClassNamePart, |
2ce6e9a6 |
166 | coerce=>1, |
167 | required=>1, |
168 | default=> 'DBIx::Class::Storage::DBI::Replicated::Balancer::First', |
64cdad22 |
169 | handles=>{ |
170 | 'create_balancer' => 'new', |
171 | }, |
2bf79155 |
172 | ); |
173 | |
17b05c13 |
174 | =head2 balancer_args |
175 | |
176 | Contains a hashref of initialized information to pass to the Balancer object. |
212cc5c2 |
177 | See L<DBIx::Class::Storage::DBI::Replicated::Balancer> for available arguments. |
17b05c13 |
178 | |
179 | =cut |
180 | |
181 | has 'balancer_args' => ( |
dcdf7b2c |
182 | is=>'rw', |
41916570 |
183 | isa=>HashRef, |
64cdad22 |
184 | lazy=>1, |
185 | required=>1, |
186 | default=>sub { {} }, |
17b05c13 |
187 | ); |
188 | |
26ab719a |
189 | =head2 pool |
2bf79155 |
190 | |
26ab719a |
191 | Is a <DBIx::Class::Storage::DBI::Replicated::Pool> or derived class. This is a |
192 | container class for one or more replicated databases. |
2bf79155 |
193 | |
194 | =cut |
195 | |
26ab719a |
196 | has 'pool' => ( |
64cdad22 |
197 | is=>'ro', |
198 | isa=>'DBIx::Class::Storage::DBI::Replicated::Pool', |
199 | lazy_build=>1, |
200 | handles=>[qw/ |
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201 | connect_replicants |
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202 | replicants |
203 | has_replicants |
204 | /], |
2bf79155 |
205 | ); |
206 | |
26ab719a |
207 | =head2 balancer |
2bf79155 |
208 | |
26ab719a |
209 | Is a <DBIx::Class::Storage::DBI::Replicated::Balancer> or derived class. This |
210 | is a class that takes a pool (<DBIx::Class::Storage::DBI::Replicated::Pool>) |
2bf79155 |
211 | |
26ab719a |
212 | =cut |
2bf79155 |
213 | |
26ab719a |
214 | has 'balancer' => ( |
dcdf7b2c |
215 | is=>'rw', |
64cdad22 |
216 | isa=>'DBIx::Class::Storage::DBI::Replicated::Balancer', |
217 | lazy_build=>1, |
218 | handles=>[qw/auto_validate_every/], |
26ab719a |
219 | ); |
2bf79155 |
220 | |
cb6ec758 |
221 | =head2 master |
222 | |
223 | The master defines the canonical state for a pool of connected databases. All |
224 | the replicants are expected to match this databases state. Thus, in a classic |
225 | Master / Slaves distributed system, all the slaves are expected to replicate |
226 | the Master's state as quick as possible. This is the only database in the |
227 | pool of databases that is allowed to handle write traffic. |
228 | |
229 | =cut |
230 | |
231 | has 'master' => ( |
64cdad22 |
232 | is=> 'ro', |
6a151f58 |
233 | isa=>DBICStorageDBI, |
64cdad22 |
234 | lazy_build=>1, |
cb6ec758 |
235 | ); |
236 | |
cb6ec758 |
237 | =head1 ATTRIBUTES IMPLEMENTING THE DBIx::Storage::DBI INTERFACE |
238 | |
239 | The following methods are delegated all the methods required for the |
240 | L<DBIx::Class::Storage::DBI> interface. |
241 | |
242 | =head2 read_handler |
243 | |
244 | Defines an object that implements the read side of L<BIx::Class::Storage::DBI>. |
245 | |
246 | =cut |
247 | |
248 | has 'read_handler' => ( |
64cdad22 |
249 | is=>'rw', |
41916570 |
250 | isa=>Object, |
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251 | lazy_build=>1, |
252 | handles=>[qw/ |
253 | select |
254 | select_single |
255 | columns_info_for |
3244fdcc |
256 | _dbh_columns_info_for |
257 | _select |
6f7344b8 |
258 | /], |
cb6ec758 |
259 | ); |
260 | |
cb6ec758 |
261 | =head2 write_handler |
262 | |
3244fdcc |
263 | Defines an object that implements the write side of L<BIx::Class::Storage::DBI>, |
264 | as well as methods that don't write or read that can be called on only one |
265 | storage, methods that return a C<$dbh>, and any methods that don't make sense to |
266 | run on a replicant. |
cb6ec758 |
267 | |
268 | =cut |
269 | |
270 | has 'write_handler' => ( |
64cdad22 |
271 | is=>'ro', |
41916570 |
272 | isa=>Object, |
64cdad22 |
273 | lazy_build=>1, |
6f7344b8 |
274 | handles=>[qw/ |
64cdad22 |
275 | on_connect_do |
6f7344b8 |
276 | on_disconnect_do |
3244fdcc |
277 | on_connect_call |
278 | on_disconnect_call |
64cdad22 |
279 | connect_info |
3244fdcc |
280 | _connect_info |
64cdad22 |
281 | throw_exception |
282 | sql_maker |
283 | sqlt_type |
284 | create_ddl_dir |
285 | deployment_statements |
286 | datetime_parser |
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287 | datetime_parser_type |
288 | build_datetime_parser |
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289 | last_insert_id |
290 | insert |
291 | insert_bulk |
292 | update |
293 | delete |
294 | dbh |
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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 |
6f7344b8 |
303 | dbh_do |
64cdad22 |
304 | reload_row |
6f7344b8 |
305 | with_deferred_fk_checks |
2ce6e9a6 |
306 | _prep_for_execute |
7fb60fb1 |
307 | |
6f7344b8 |
308 | backup |
309 | is_datatype_numeric |
227d8366 |
310 | _supports_insert_returning |
6f7344b8 |
311 | _count_select |
6f7344b8 |
312 | _subq_update_delete |
313 | svp_rollback |
314 | svp_begin |
315 | svp_release |
e398f77e |
316 | relname_to_table_alias |
317 | _straight_join_to_node |
3244fdcc |
318 | _dbh_last_insert_id |
319 | _fix_bind_params |
320 | _default_dbi_connect_attributes |
321 | _dbi_connect_info |
322 | auto_savepoint |
323 | _sqlt_version_ok |
324 | _query_end |
325 | bind_attribute_by_data_type |
326 | transaction_depth |
327 | _dbh |
328 | _select_args |
329 | _dbh_execute_array |
330 | _sql_maker_args |
331 | _sql_maker |
332 | _query_start |
333 | _sqlt_version_error |
334 | _per_row_update_delete |
335 | _dbh_begin_work |
336 | _dbh_execute_inserts_with_no_binds |
337 | _select_args_to_query |
338 | _svp_generate_name |
339 | _multipk_update_delete |
340 | source_bind_attributes |
341 | _normalize_connect_info |
342 | _parse_connect_do |
343 | _dbh_commit |
344 | _execute_array |
345 | _placeholders_supported |
3244fdcc |
346 | savepoints |
347 | _sqlt_minimum_version |
348 | _sql_maker_opts |
349 | _conn_pid |
350 | _typeless_placeholders_supported |
351 | _conn_tid |
352 | _dbh_autocommit |
353 | _native_data_type |
354 | _get_dbh |
355 | sql_maker_class |
356 | _dbh_rollback |
357 | _adjust_select_args_for_complex_prefetch |
358 | _resolve_ident_sources |
359 | _resolve_column_info |
360 | _prune_unused_joins |
361 | _strip_cond_qualifiers |
362 | _parse_order_by |
363 | _resolve_aliastypes_from_select_args |
364 | _execute |
365 | _do_query |
366 | _dbh_sth |
367 | _dbh_execute |
6ed1cd2e |
368 | _prefetch_insert_auto_nextvals |
6d766626 |
369 | _server_info_hash |
64cdad22 |
370 | /], |
cb6ec758 |
371 | ); |
372 | |
e471ab87 |
373 | my @unimplemented = qw( |
374 | _arm_global_destructor |
375 | _preserve_foreign_dbh |
572338e0 |
376 | _verify_pid |
377 | _verify_tid |
e471ab87 |
378 | ); |
379 | |
380 | for my $method (@unimplemented) { |
381 | __PACKAGE__->meta->add_method($method, sub { |
382 | croak "$method must not be called on ".(blessed shift).' objects'; |
383 | }); |
384 | } |
6d766626 |
385 | |
b2e4d522 |
386 | has _master_connect_info_opts => |
387 | (is => 'rw', isa => HashRef, default => sub { {} }); |
388 | |
389 | =head2 around: connect_info |
390 | |
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391 | Preserves master's C<connect_info> options (for merging with replicants.) |
392 | Also sets any Replicated-related options from connect_info, such as |
dcdf7b2c |
393 | C<pool_type>, C<pool_args>, C<balancer_type> and C<balancer_args>. |
b2e4d522 |
394 | |
395 | =cut |
396 | |
397 | around connect_info => sub { |
398 | my ($next, $self, $info, @extra) = @_; |
399 | |
0ce2d0d5 |
400 | my $wantarray = wantarray; |
401 | |
282a9a4f |
402 | my $merge = Hash::Merge->new('LEFT_PRECEDENT'); |
e666c5fd |
403 | |
b2e4d522 |
404 | my %opts; |
405 | for my $arg (@$info) { |
406 | next unless (reftype($arg)||'') eq 'HASH'; |
e666c5fd |
407 | %opts = %{ $merge->merge($arg, \%opts) }; |
b2e4d522 |
408 | } |
b2e4d522 |
409 | delete $opts{dsn}; |
410 | |
dcdf7b2c |
411 | if (@opts{qw/pool_type pool_args/}) { |
412 | $self->pool_type(delete $opts{pool_type}) |
413 | if $opts{pool_type}; |
414 | |
b88b85e7 |
415 | $self->pool_args( |
e666c5fd |
416 | $merge->merge((delete $opts{pool_args} || {}), $self->pool_args) |
b88b85e7 |
417 | ); |
dcdf7b2c |
418 | |
67c43863 |
419 | $self->pool($self->_build_pool) |
6f7344b8 |
420 | if $self->pool; |
dcdf7b2c |
421 | } |
422 | |
423 | if (@opts{qw/balancer_type balancer_args/}) { |
424 | $self->balancer_type(delete $opts{balancer_type}) |
425 | if $opts{balancer_type}; |
426 | |
b88b85e7 |
427 | $self->balancer_args( |
e666c5fd |
428 | $merge->merge((delete $opts{balancer_args} || {}), $self->balancer_args) |
b88b85e7 |
429 | ); |
dcdf7b2c |
430 | |
67c43863 |
431 | $self->balancer($self->_build_balancer) |
6f7344b8 |
432 | if $self->balancer; |
dcdf7b2c |
433 | } |
434 | |
b2e4d522 |
435 | $self->_master_connect_info_opts(\%opts); |
436 | |
0ce2d0d5 |
437 | my (@res, $res); |
438 | if ($wantarray) { |
439 | @res = $self->$next($info, @extra); |
440 | } else { |
441 | $res = $self->$next($info, @extra); |
442 | } |
443 | |
fd4eb9c2 |
444 | # Make sure master is blessed into the correct class and apply role to it. |
445 | my $master = $self->master; |
446 | $master->_determine_driver; |
447 | Moose::Meta::Class->initialize(ref $master); |
cea43436 |
448 | |
ec0946db |
449 | DBIx::Class::Storage::DBI::Replicated::WithDSN->meta->apply($master); |
cea43436 |
450 | |
451 | # link pool back to master |
452 | $self->pool->master($master); |
0ce2d0d5 |
453 | |
454 | $wantarray ? @res : $res; |
b2e4d522 |
455 | }; |
456 | |
26ab719a |
457 | =head1 METHODS |
2bf79155 |
458 | |
26ab719a |
459 | This class defines the following methods. |
2bf79155 |
460 | |
c354902c |
461 | =head2 BUILDARGS |
2bf79155 |
462 | |
faaba25f |
463 | L<DBIx::Class::Schema> when instantiating its storage passed itself as the |
2ce6e9a6 |
464 | first argument. So we need to massage the arguments a bit so that all the |
465 | bits get put into the correct places. |
2bf79155 |
466 | |
467 | =cut |
468 | |
c354902c |
469 | sub BUILDARGS { |
d7a58a29 |
470 | my ($class, $schema, $storage_type_args, @args) = @_; |
d4daee7b |
471 | |
c354902c |
472 | return { |
6f7344b8 |
473 | schema=>$schema, |
474 | %$storage_type_args, |
475 | @args |
c354902c |
476 | } |
477 | } |
2bf79155 |
478 | |
cb6ec758 |
479 | =head2 _build_master |
2bf79155 |
480 | |
cb6ec758 |
481 | Lazy builder for the L</master> attribute. |
2bf79155 |
482 | |
483 | =cut |
484 | |
cb6ec758 |
485 | sub _build_master { |
2ce6e9a6 |
486 | my $self = shift @_; |
ee356d00 |
487 | my $master = DBIx::Class::Storage::DBI->new($self->schema); |
ee356d00 |
488 | $master |
106d5f3b |
489 | } |
490 | |
26ab719a |
491 | =head2 _build_pool |
2bf79155 |
492 | |
26ab719a |
493 | Lazy builder for the L</pool> attribute. |
2bf79155 |
494 | |
495 | =cut |
496 | |
26ab719a |
497 | sub _build_pool { |
64cdad22 |
498 | my $self = shift @_; |
499 | $self->create_pool(%{$self->pool_args}); |
2bf79155 |
500 | } |
501 | |
26ab719a |
502 | =head2 _build_balancer |
2bf79155 |
503 | |
cb6ec758 |
504 | Lazy builder for the L</balancer> attribute. This takes a Pool object so that |
505 | the balancer knows which pool it's balancing. |
2bf79155 |
506 | |
507 | =cut |
508 | |
26ab719a |
509 | sub _build_balancer { |
64cdad22 |
510 | my $self = shift @_; |
511 | $self->create_balancer( |
6f7344b8 |
512 | pool=>$self->pool, |
64cdad22 |
513 | master=>$self->master, |
514 | %{$self->balancer_args}, |
515 | ); |
2bf79155 |
516 | } |
517 | |
cb6ec758 |
518 | =head2 _build_write_handler |
2bf79155 |
519 | |
cb6ec758 |
520 | Lazy builder for the L</write_handler> attribute. The default is to set this to |
521 | the L</master>. |
50336325 |
522 | |
523 | =cut |
524 | |
cb6ec758 |
525 | sub _build_write_handler { |
64cdad22 |
526 | return shift->master; |
cb6ec758 |
527 | } |
50336325 |
528 | |
cb6ec758 |
529 | =head2 _build_read_handler |
2bf79155 |
530 | |
cb6ec758 |
531 | Lazy builder for the L</read_handler> attribute. The default is to set this to |
532 | the L</balancer>. |
2bf79155 |
533 | |
534 | =cut |
535 | |
cb6ec758 |
536 | sub _build_read_handler { |
64cdad22 |
537 | return shift->balancer; |
cb6ec758 |
538 | } |
50336325 |
539 | |
cb6ec758 |
540 | =head2 around: connect_replicants |
2bf79155 |
541 | |
cb6ec758 |
542 | All calls to connect_replicants needs to have an existing $schema tacked onto |
b2e4d522 |
543 | top of the args, since L<DBIx::Storage::DBI> needs it, and any C<connect_info> |
544 | options merged with the master, with replicant opts having higher priority. |
955a6df6 |
545 | |
cb6ec758 |
546 | =cut |
955a6df6 |
547 | |
b2e4d522 |
548 | around connect_replicants => sub { |
549 | my ($next, $self, @args) = @_; |
550 | |
551 | for my $r (@args) { |
552 | $r = [ $r ] unless reftype $r eq 'ARRAY'; |
553 | |
1a58752c |
554 | $self->throw_exception('coderef replicant connect_info not supported') |
b2e4d522 |
555 | if ref $r->[0] && reftype $r->[0] eq 'CODE'; |
556 | |
557 | # any connect_info options? |
558 | my $i = 0; |
559 | $i++ while $i < @$r && (reftype($r->[$i])||'') ne 'HASH'; |
560 | |
6f7344b8 |
561 | # make one if none |
b2e4d522 |
562 | $r->[$i] = {} unless $r->[$i]; |
563 | |
564 | # merge if two hashes |
b88b85e7 |
565 | my @hashes = @$r[$i .. $#{$r}]; |
566 | |
1a58752c |
567 | $self->throw_exception('invalid connect_info options') |
b88b85e7 |
568 | if (grep { reftype($_) eq 'HASH' } @hashes) != @hashes; |
569 | |
1a58752c |
570 | $self->throw_exception('too many hashrefs in connect_info') |
b88b85e7 |
571 | if @hashes > 2; |
572 | |
282a9a4f |
573 | my $merge = Hash::Merge->new('LEFT_PRECEDENT'); |
e666c5fd |
574 | my %opts = %{ $merge->merge(reverse @hashes) }; |
b88b85e7 |
575 | |
576 | # delete them |
b2e4d522 |
577 | splice @$r, $i+1, ($#{$r} - $i), (); |
578 | |
0bd8e058 |
579 | # make sure master/replicants opts don't clash |
580 | my %master_opts = %{ $self->_master_connect_info_opts }; |
581 | if (exists $opts{dbh_maker}) { |
582 | delete @master_opts{qw/dsn user password/}; |
583 | } |
584 | delete $master_opts{dbh_maker}; |
585 | |
b2e4d522 |
586 | # merge with master |
e666c5fd |
587 | %opts = %{ $merge->merge(\%opts, \%master_opts) }; |
b2e4d522 |
588 | |
589 | # update |
590 | $r->[$i] = \%opts; |
591 | } |
592 | |
593 | $self->$next($self->schema, @args); |
955a6df6 |
594 | }; |
2bf79155 |
595 | |
2bf79155 |
596 | =head2 all_storages |
597 | |
598 | Returns an array of of all the connected storage backends. The first element |
599 | in the returned array is the master, and the remainings are each of the |
600 | replicants. |
601 | |
602 | =cut |
603 | |
604 | sub all_storages { |
64cdad22 |
605 | my $self = shift @_; |
606 | return grep {defined $_ && blessed $_} ( |
607 | $self->master, |
6412a592 |
608 | values %{ $self->replicants }, |
64cdad22 |
609 | ); |
2bf79155 |
610 | } |
611 | |
c4d3fae2 |
612 | =head2 execute_reliably ($coderef, ?@args) |
613 | |
614 | Given a coderef, saves the current state of the L</read_handler>, forces it to |
48580715 |
615 | use reliable storage (e.g. sets it to the master), executes a coderef and then |
c4d3fae2 |
616 | restores the original state. |
617 | |
618 | Example: |
619 | |
64cdad22 |
620 | my $reliably = sub { |
621 | my $name = shift @_; |
622 | $schema->resultset('User')->create({name=>$name}); |
623 | my $user_rs = $schema->resultset('User')->find({name=>$name}); |
624 | return $user_rs; |
625 | }; |
c4d3fae2 |
626 | |
64cdad22 |
627 | my $user_rs = $schema->storage->execute_reliably($reliably, 'John'); |
c4d3fae2 |
628 | |
629 | Use this when you must be certain of your database state, such as when you just |
630 | inserted something and need to get a resultset including it, etc. |
631 | |
632 | =cut |
633 | |
634 | sub execute_reliably { |
64cdad22 |
635 | my ($self, $coderef, @args) = @_; |
d4daee7b |
636 | |
64cdad22 |
637 | unless( ref $coderef eq 'CODE') { |
638 | $self->throw_exception('Second argument must be a coderef'); |
639 | } |
d4daee7b |
640 | |
64cdad22 |
641 | ##Get copy of master storage |
642 | my $master = $self->master; |
d4daee7b |
643 | |
64cdad22 |
644 | ##Get whatever the current read hander is |
645 | my $current = $self->read_handler; |
d4daee7b |
646 | |
64cdad22 |
647 | ##Set the read handler to master |
648 | $self->read_handler($master); |
d4daee7b |
649 | |
64cdad22 |
650 | ## do whatever the caller needs |
651 | my @result; |
652 | my $want_array = wantarray; |
d4daee7b |
653 | |
ed7ab0f4 |
654 | try { |
64cdad22 |
655 | if($want_array) { |
656 | @result = $coderef->(@args); |
657 | } elsif(defined $want_array) { |
658 | ($result[0]) = ($coderef->(@args)); |
ed213e85 |
659 | } else { |
64cdad22 |
660 | $coderef->(@args); |
6f7344b8 |
661 | } |
ed7ab0f4 |
662 | } catch { |
663 | $self->throw_exception("coderef returned an error: $_"); |
664 | } finally { |
665 | ##Reset to the original state |
666 | $self->read_handler($current); |
64cdad22 |
667 | }; |
d4daee7b |
668 | |
ed7ab0f4 |
669 | return $want_array ? @result : $result[0]; |
c4d3fae2 |
670 | } |
671 | |
cb6ec758 |
672 | =head2 set_reliable_storage |
673 | |
674 | Sets the current $schema to be 'reliable', that is all queries, both read and |
675 | write are sent to the master |
d4daee7b |
676 | |
cb6ec758 |
677 | =cut |
678 | |
679 | sub set_reliable_storage { |
64cdad22 |
680 | my $self = shift @_; |
681 | my $schema = $self->schema; |
682 | my $write_handler = $self->schema->storage->write_handler; |
d4daee7b |
683 | |
64cdad22 |
684 | $schema->storage->read_handler($write_handler); |
cb6ec758 |
685 | } |
686 | |
687 | =head2 set_balanced_storage |
688 | |
689 | Sets the current $schema to be use the </balancer> for all reads, while all |
48580715 |
690 | writes are sent to the master only |
d4daee7b |
691 | |
cb6ec758 |
692 | =cut |
693 | |
694 | sub set_balanced_storage { |
64cdad22 |
695 | my $self = shift @_; |
696 | my $schema = $self->schema; |
bd5da369 |
697 | my $balanced_handler = $self->schema->storage->balancer; |
d4daee7b |
698 | |
bd5da369 |
699 | $schema->storage->read_handler($balanced_handler); |
cb6ec758 |
700 | } |
2bf79155 |
701 | |
702 | =head2 connected |
703 | |
704 | Check that the master and at least one of the replicants is connected. |
705 | |
706 | =cut |
707 | |
708 | sub connected { |
64cdad22 |
709 | my $self = shift @_; |
710 | return |
711 | $self->master->connected && |
712 | $self->pool->connected_replicants; |
2bf79155 |
713 | } |
714 | |
2bf79155 |
715 | =head2 ensure_connected |
716 | |
717 | Make sure all the storages are connected. |
718 | |
719 | =cut |
720 | |
721 | sub ensure_connected { |
64cdad22 |
722 | my $self = shift @_; |
723 | foreach my $source ($self->all_storages) { |
724 | $source->ensure_connected(@_); |
725 | } |
2bf79155 |
726 | } |
727 | |
2bf79155 |
728 | =head2 limit_dialect |
729 | |
730 | Set the limit_dialect for all existing storages |
731 | |
732 | =cut |
733 | |
734 | sub limit_dialect { |
64cdad22 |
735 | my $self = shift @_; |
736 | foreach my $source ($self->all_storages) { |
737 | $source->limit_dialect(@_); |
738 | } |
3fbe08e3 |
739 | return $self->master->quote_char; |
2bf79155 |
740 | } |
741 | |
2bf79155 |
742 | =head2 quote_char |
743 | |
744 | Set the quote_char for all existing storages |
745 | |
746 | =cut |
747 | |
748 | sub quote_char { |
64cdad22 |
749 | my $self = shift @_; |
750 | foreach my $source ($self->all_storages) { |
751 | $source->quote_char(@_); |
752 | } |
3fbe08e3 |
753 | return $self->master->quote_char; |
2bf79155 |
754 | } |
755 | |
2bf79155 |
756 | =head2 name_sep |
757 | |
758 | Set the name_sep for all existing storages |
759 | |
760 | =cut |
761 | |
762 | sub name_sep { |
64cdad22 |
763 | my $self = shift @_; |
764 | foreach my $source ($self->all_storages) { |
765 | $source->name_sep(@_); |
766 | } |
3fbe08e3 |
767 | return $self->master->name_sep; |
2bf79155 |
768 | } |
769 | |
2bf79155 |
770 | =head2 set_schema |
771 | |
772 | Set the schema object for all existing storages |
773 | |
774 | =cut |
775 | |
776 | sub set_schema { |
64cdad22 |
777 | my $self = shift @_; |
778 | foreach my $source ($self->all_storages) { |
779 | $source->set_schema(@_); |
780 | } |
2bf79155 |
781 | } |
782 | |
2bf79155 |
783 | =head2 debug |
784 | |
785 | set a debug flag across all storages |
786 | |
787 | =cut |
788 | |
789 | sub debug { |
64cdad22 |
790 | my $self = shift @_; |
3fbe08e3 |
791 | if(@_) { |
792 | foreach my $source ($self->all_storages) { |
793 | $source->debug(@_); |
6f7344b8 |
794 | } |
64cdad22 |
795 | } |
3fbe08e3 |
796 | return $self->master->debug; |
2bf79155 |
797 | } |
798 | |
2bf79155 |
799 | =head2 debugobj |
800 | |
cea43436 |
801 | set a debug object |
2bf79155 |
802 | |
803 | =cut |
804 | |
805 | sub debugobj { |
64cdad22 |
806 | my $self = shift @_; |
cea43436 |
807 | return $self->master->debugobj(@_); |
2bf79155 |
808 | } |
809 | |
2bf79155 |
810 | =head2 debugfh |
811 | |
cea43436 |
812 | set a debugfh object |
2bf79155 |
813 | |
814 | =cut |
815 | |
816 | sub debugfh { |
64cdad22 |
817 | my $self = shift @_; |
cea43436 |
818 | return $self->master->debugfh(@_); |
2bf79155 |
819 | } |
820 | |
2bf79155 |
821 | =head2 debugcb |
822 | |
cea43436 |
823 | set a debug callback |
2bf79155 |
824 | |
825 | =cut |
826 | |
827 | sub debugcb { |
64cdad22 |
828 | my $self = shift @_; |
cea43436 |
829 | return $self->master->debugcb(@_); |
2bf79155 |
830 | } |
831 | |
2bf79155 |
832 | =head2 disconnect |
833 | |
834 | disconnect everything |
835 | |
836 | =cut |
837 | |
838 | sub disconnect { |
64cdad22 |
839 | my $self = shift @_; |
840 | foreach my $source ($self->all_storages) { |
841 | $source->disconnect(@_); |
842 | } |
2bf79155 |
843 | } |
844 | |
b2e4d522 |
845 | =head2 cursor_class |
846 | |
847 | set cursor class on all storages, or return master's |
848 | |
849 | =cut |
850 | |
851 | sub cursor_class { |
852 | my ($self, $cursor_class) = @_; |
853 | |
854 | if ($cursor_class) { |
855 | $_->cursor_class($cursor_class) for $self->all_storages; |
856 | } |
857 | $self->master->cursor_class; |
858 | } |
d4daee7b |
859 | |
3244fdcc |
860 | =head2 cursor |
861 | |
862 | set cursor class on all storages, or return master's, alias for L</cursor_class> |
863 | above. |
864 | |
865 | =cut |
866 | |
867 | sub cursor { |
868 | my ($self, $cursor_class) = @_; |
869 | |
870 | if ($cursor_class) { |
871 | $_->cursor($cursor_class) for $self->all_storages; |
872 | } |
873 | $self->master->cursor; |
874 | } |
875 | |
876 | =head2 unsafe |
877 | |
878 | sets the L<DBIx::Class::Storage::DBI/unsafe> option on all storages or returns |
879 | master's current setting |
880 | |
881 | =cut |
882 | |
883 | sub unsafe { |
884 | my $self = shift; |
885 | |
886 | if (@_) { |
887 | $_->unsafe(@_) for $self->all_storages; |
888 | } |
889 | |
890 | return $self->master->unsafe; |
891 | } |
892 | |
893 | =head2 disable_sth_caching |
894 | |
895 | sets the L<DBIx::Class::Storage::DBI/disable_sth_caching> option on all storages |
896 | or returns master's current setting |
897 | |
898 | =cut |
899 | |
900 | sub disable_sth_caching { |
901 | my $self = shift; |
902 | |
903 | if (@_) { |
904 | $_->disable_sth_caching(@_) for $self->all_storages; |
905 | } |
906 | |
907 | return $self->master->disable_sth_caching; |
908 | } |
909 | |
910 | =head2 lag_behind_master |
911 | |
912 | returns the highest Replicant L<DBIx::Class::Storage::DBI/lag_behind_master> |
913 | setting |
914 | |
915 | =cut |
916 | |
917 | sub lag_behind_master { |
918 | my $self = shift; |
919 | |
920 | return max map $_->lag_behind_master, $self->replicants; |
921 | } |
922 | |
923 | =head2 is_replicating |
924 | |
925 | returns true if all replicants return true for |
926 | L<DBIx::Class::Storage::DBI/is_replicating> |
927 | |
928 | =cut |
929 | |
930 | sub is_replicating { |
931 | my $self = shift; |
932 | |
933 | return (grep $_->is_replicating, $self->replicants) == ($self->replicants); |
934 | } |
935 | |
936 | =head2 connect_call_datetime_setup |
937 | |
938 | calls L<DBIx::Class::Storage::DBI/connect_call_datetime_setup> for all storages |
939 | |
940 | =cut |
941 | |
942 | sub connect_call_datetime_setup { |
943 | my $self = shift; |
944 | $_->connect_call_datetime_setup for $self->all_storages; |
945 | } |
946 | |
947 | sub _populate_dbh { |
948 | my $self = shift; |
949 | $_->_populate_dbh for $self->all_storages; |
950 | } |
951 | |
952 | sub _connect { |
953 | my $self = shift; |
954 | $_->_connect for $self->all_storages; |
955 | } |
956 | |
957 | sub _rebless { |
958 | my $self = shift; |
959 | $_->_rebless for $self->all_storages; |
960 | } |
961 | |
962 | sub _determine_driver { |
963 | my $self = shift; |
964 | $_->_determine_driver for $self->all_storages; |
965 | } |
966 | |
967 | sub _driver_determined { |
968 | my $self = shift; |
969 | |
970 | if (@_) { |
971 | $_->_driver_determined(@_) for $self->all_storages; |
972 | } |
973 | |
974 | return $self->master->_driver_determined; |
975 | } |
976 | |
977 | sub _init { |
978 | my $self = shift; |
979 | |
980 | $_->_init for $self->all_storages; |
981 | } |
982 | |
983 | sub _run_connection_actions { |
984 | my $self = shift; |
985 | |
986 | $_->_run_connection_actions for $self->all_storages; |
987 | } |
988 | |
989 | sub _do_connection_actions { |
990 | my $self = shift; |
991 | |
992 | if (@_) { |
993 | $_->_do_connection_actions(@_) for $self->all_storages; |
994 | } |
995 | } |
996 | |
997 | sub connect_call_do_sql { |
998 | my $self = shift; |
999 | $_->connect_call_do_sql(@_) for $self->all_storages; |
1000 | } |
1001 | |
1002 | sub disconnect_call_do_sql { |
1003 | my $self = shift; |
1004 | $_->disconnect_call_do_sql(@_) for $self->all_storages; |
1005 | } |
1006 | |
1007 | sub _seems_connected { |
1008 | my $self = shift; |
1009 | |
1010 | return min map $_->_seems_connected, $self->all_storages; |
1011 | } |
1012 | |
1013 | sub _ping { |
1014 | my $self = shift; |
1015 | |
1016 | return min map $_->_ping, $self->all_storages; |
1017 | } |
1018 | |
7da56142 |
1019 | my $numify_ver = sub { |
1020 | my $ver = shift; |
1021 | my @numparts = split /\D+/, $ver; |
1022 | my $format = '%d.' . (join '', ('%05d') x (@numparts - 1)); |
1023 | |
1024 | return sprintf $format, @numparts; |
1025 | }; |
1026 | |
fecb38cb |
1027 | sub _server_info { |
1028 | my $self = shift; |
1029 | |
1030 | if (not $self->_server_info_hash) { |
7da56142 |
1031 | my $min_version_info = ( |
1032 | reduce { $a->[0] < $b->[0] ? $a : $b } |
1033 | map [ $numify_ver->($_->{dbms_version}), $_ ], |
1034 | map $_->_server_info, $self->all_storages |
1035 | )->[1]; |
fecb38cb |
1036 | |
1037 | $self->_server_info_hash($min_version_info); # on master |
1038 | } |
1039 | |
1040 | return $self->_server_info_hash; |
1041 | } |
1042 | |
1043 | sub _get_server_version { |
1044 | my $self = shift; |
1045 | |
1046 | return $self->_server_info->{dbms_version}; |
1047 | } |
1048 | |
7e38d850 |
1049 | =head1 GOTCHAS |
1050 | |
1051 | Due to the fact that replicants can lag behind a master, you must take care to |
1052 | make sure you use one of the methods to force read queries to a master should |
1053 | you need realtime data integrity. For example, if you insert a row, and then |
1054 | immediately re-read it from the database (say, by doing $row->discard_changes) |
1055 | or you insert a row and then immediately build a query that expects that row |
1056 | to be an item, you should force the master to handle reads. Otherwise, due to |
1057 | the lag, there is no certainty your data will be in the expected state. |
1058 | |
1059 | For data integrity, all transactions automatically use the master storage for |
1060 | all read and write queries. Using a transaction is the preferred and recommended |
1061 | method to force the master to handle all read queries. |
1062 | |
1063 | Otherwise, you can force a single query to use the master with the 'force_pool' |
1064 | attribute: |
1065 | |
1066 | my $row = $resultset->search(undef, {force_pool=>'master'})->find($pk); |
1067 | |
1068 | This attribute will safely be ignore by non replicated storages, so you can use |
1069 | the same code for both types of systems. |
1070 | |
1071 | Lastly, you can use the L</execute_reliably> method, which works very much like |
1072 | a transaction. |
1073 | |
1074 | For debugging, you can turn replication on/off with the methods L</set_reliable_storage> |
1075 | and L</set_balanced_storage>, however this operates at a global level and is not |
1076 | suitable if you have a shared Schema object being used by multiple processes, |
1077 | such as on a web application server. You can get around this limitation by |
1078 | using the Schema clone method. |
1079 | |
1080 | my $new_schema = $schema->clone; |
1081 | $new_schema->set_reliable_storage; |
d4daee7b |
1082 | |
7e38d850 |
1083 | ## $new_schema will use only the Master storage for all reads/writes while |
1084 | ## the $schema object will use replicated storage. |
1085 | |
f5d3a5de |
1086 | =head1 AUTHOR |
1087 | |
64cdad22 |
1088 | John Napiorkowski <john.napiorkowski@takkle.com> |
f5d3a5de |
1089 | |
c4d3fae2 |
1090 | Based on code originated by: |
f5d3a5de |
1091 | |
64cdad22 |
1092 | Norbert Csongrádi <bert@cpan.org> |
1093 | Peter Siklósi <einon@einon.hu> |
2156bbdd |
1094 | |
f5d3a5de |
1095 | =head1 LICENSE |
1096 | |
1097 | You may distribute this code under the same terms as Perl itself. |
1098 | |
1099 | =cut |
1100 | |
c354902c |
1101 | __PACKAGE__->meta->make_immutable; |
1102 | |
f5d3a5de |
1103 | 1; |