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