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1 | package DBIx::Class::Storage::DBI::Replicated; |
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2 | |
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3 | use warnings; |
4 | use strict; |
5 | |
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6 | BEGIN { |
c96bf2bc |
7 | require DBIx::Class::Optional::Dependencies; |
8 | if ( my $missing = DBIx::Class::Optional::Dependencies->req_missing_for('replicated') ) { |
9 | die "The following modules are required for Replicated storage support: $missing\n"; |
10 | } |
ecb65397 |
11 | } |
12 | |
b2e4d522 |
13 | use Moose; |
26ab719a |
14 | use DBIx::Class::Storage::DBI; |
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15 | use DBIx::Class::Storage::DBI::Replicated::Pool; |
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16 | use DBIx::Class::Storage::DBI::Replicated::Balancer; |
6a151f58 |
17 | use DBIx::Class::Storage::DBI::Replicated::Types qw/BalancerClassNamePart DBICSchema DBICStorageDBI/; |
41916570 |
18 | use MooseX::Types::Moose qw/ClassName HashRef Object/; |
b2e4d522 |
19 | use Scalar::Util 'reftype'; |
e666c5fd |
20 | use Hash::Merge; |
7da56142 |
21 | use List::Util qw/min max reduce/; |
1abccf54 |
22 | use Context::Preserve 'preserve_context'; |
ed7ab0f4 |
23 | use Try::Tiny; |
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24 | |
25 | use namespace::clean -except => 'meta'; |
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26 | |
27 | =head1 NAME |
28 | |
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29 | DBIx::Class::Storage::DBI::Replicated - BETA Replicated database support |
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30 | |
31 | =head1 SYNOPSIS |
32 | |
33 | The Following example shows how to change an existing $schema to a replicated |
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34 | storage type, add some replicated (read-only) databases, and perform reporting |
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35 | tasks. |
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36 | |
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37 | You should set the 'storage_type attribute to a replicated type. You should |
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38 | also define your arguments, such as which balancer you want and any arguments |
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39 | that the Pool object should get. |
40 | |
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41 | my $schema = Schema::Class->clone; |
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42 | $schema->storage_type(['::DBI::Replicated', { balancer_type => '::Random' }]); |
ce854fd3 |
43 | $schema->connection(...); |
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44 | |
fd323bf1 |
45 | Next, you need to add in the Replicants. Basically this is an array of |
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46 | arrayrefs, where each arrayref is database connect information. Think of these |
47 | arguments as what you'd pass to the 'normal' $schema->connect method. |
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48 | |
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49 | $schema->storage->connect_replicants( |
50 | [$dsn1, $user, $pass, \%opts], |
51 | [$dsn2, $user, $pass, \%opts], |
52 | [$dsn3, $user, $pass, \%opts], |
53 | ); |
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54 | |
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55 | Now, just use the $schema as you normally would. Automatically all reads will |
56 | be delegated to the replicants, while writes to the master. |
57 | |
7e38d850 |
58 | $schema->resultset('Source')->search({name=>'etc'}); |
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59 | |
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60 | You can force a given query to use a particular storage using the search |
61 | attribute 'force_pool'. For example: |
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62 | |
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63 | my $rs = $schema->resultset('Source')->search(undef, {force_pool=>'master'}); |
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64 | |
d7c37d66 |
65 | Now $rs will force everything (both reads and writes) to use whatever was setup |
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66 | as the master storage. 'master' is hardcoded to always point to the Master, |
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67 | but you can also use any Replicant name. Please see: |
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68 | L<DBIx::Class::Storage::DBI::Replicated::Pool> and the replicants attribute for more. |
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69 | |
70 | Also see transactions and L</execute_reliably> for alternative ways to |
71 | force read traffic to the master. In general, you should wrap your statements |
72 | in a transaction when you are reading and writing to the same tables at the |
73 | same time, since your replicants will often lag a bit behind the master. |
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74 | |
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75 | If you have a multi-statement read only transaction you can force it to select |
76 | a random server in the pool by: |
77 | |
78 | my $rs = $schema->resultset('Source')->search( undef, |
79 | { force_pool => $db->storage->read_handler->next_storage } |
80 | ); |
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81 | |
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82 | =head1 DESCRIPTION |
83 | |
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84 | Warning: This class is marked BETA. This has been running a production |
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85 | website using MySQL native replication as its backend and we have some decent |
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86 | test coverage but the code hasn't yet been stressed by a variety of databases. |
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87 | Individual DBs may have quirks we are not aware of. Please use this in first |
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88 | development and pass along your experiences/bug fixes. |
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89 | |
90 | This class implements replicated data store for DBI. Currently you can define |
91 | one master and numerous slave database connections. All write-type queries |
92 | (INSERT, UPDATE, DELETE and even LAST_INSERT_ID) are routed to master |
93 | database, all read-type queries (SELECTs) go to the slave database. |
94 | |
95 | Basically, any method request that L<DBIx::Class::Storage::DBI> would normally |
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96 | handle gets delegated to one of the two attributes: L</read_handler> or to |
97 | L</write_handler>. Additionally, some methods need to be distributed |
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98 | to all existing storages. This way our storage class is a drop in replacement |
99 | for L<DBIx::Class::Storage::DBI>. |
100 | |
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101 | Read traffic is spread across the replicants (slaves) occurring to a user |
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102 | selected algorithm. The default algorithm is random weighted. |
103 | |
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104 | =head1 NOTES |
105 | |
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106 | The consistency between master and replicants is database specific. The Pool |
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107 | gives you a method to validate its replicants, removing and replacing them |
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108 | when they fail/pass predefined criteria. Please make careful use of the ways |
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109 | to force a query to run against Master when needed. |
110 | |
111 | =head1 REQUIREMENTS |
112 | |
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113 | Replicated Storage has additional requirements not currently part of |
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114 | L<DBIx::Class>. See L<DBIx::Class::Optional::Dependencies> for more details. |
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115 | |
116 | =head1 ATTRIBUTES |
117 | |
118 | This class defines the following attributes. |
119 | |
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120 | =head2 schema |
121 | |
122 | The underlying L<DBIx::Class::Schema> object this storage is attaching |
123 | |
124 | =cut |
125 | |
126 | has 'schema' => ( |
127 | is=>'rw', |
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128 | isa=>DBICSchema, |
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129 | weak_ref=>1, |
130 | required=>1, |
131 | ); |
132 | |
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133 | =head2 pool_type |
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134 | |
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135 | Contains the classname which will instantiate the L</pool> object. Defaults |
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136 | to: L<DBIx::Class::Storage::DBI::Replicated::Pool>. |
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137 | |
138 | =cut |
139 | |
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140 | has 'pool_type' => ( |
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141 | is=>'rw', |
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142 | isa=>ClassName, |
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143 | default=>'DBIx::Class::Storage::DBI::Replicated::Pool', |
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144 | handles=>{ |
145 | 'create_pool' => 'new', |
146 | }, |
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147 | ); |
148 | |
f068a139 |
149 | =head2 pool_args |
150 | |
151 | Contains a hashref of initialized information to pass to the Balancer object. |
212cc5c2 |
152 | See L<DBIx::Class::Storage::DBI::Replicated::Pool> for available arguments. |
f068a139 |
153 | |
154 | =cut |
155 | |
156 | has 'pool_args' => ( |
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157 | is=>'rw', |
41916570 |
158 | isa=>HashRef, |
64cdad22 |
159 | lazy=>1, |
64cdad22 |
160 | default=>sub { {} }, |
f068a139 |
161 | ); |
162 | |
163 | |
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164 | =head2 balancer_type |
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165 | |
166 | The replication pool requires a balance class to provider the methods for |
167 | choose how to spread the query load across each replicant in the pool. |
168 | |
169 | =cut |
170 | |
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171 | has 'balancer_type' => ( |
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172 | is=>'rw', |
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173 | isa=>BalancerClassNamePart, |
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174 | coerce=>1, |
175 | required=>1, |
176 | default=> 'DBIx::Class::Storage::DBI::Replicated::Balancer::First', |
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177 | handles=>{ |
178 | 'create_balancer' => 'new', |
179 | }, |
2bf79155 |
180 | ); |
181 | |
17b05c13 |
182 | =head2 balancer_args |
183 | |
184 | Contains a hashref of initialized information to pass to the Balancer object. |
212cc5c2 |
185 | See L<DBIx::Class::Storage::DBI::Replicated::Balancer> for available arguments. |
17b05c13 |
186 | |
187 | =cut |
188 | |
189 | has 'balancer_args' => ( |
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190 | is=>'rw', |
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191 | isa=>HashRef, |
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192 | lazy=>1, |
193 | required=>1, |
194 | default=>sub { {} }, |
17b05c13 |
195 | ); |
196 | |
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197 | =head2 pool |
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198 | |
370f78d4 |
199 | Is a L<DBIx::Class::Storage::DBI::Replicated::Pool> or derived class. This is a |
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200 | container class for one or more replicated databases. |
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201 | |
202 | =cut |
203 | |
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204 | has 'pool' => ( |
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205 | is=>'ro', |
206 | isa=>'DBIx::Class::Storage::DBI::Replicated::Pool', |
207 | lazy_build=>1, |
208 | handles=>[qw/ |
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209 | connect_replicants |
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210 | replicants |
211 | has_replicants |
212 | /], |
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213 | ); |
214 | |
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215 | =head2 balancer |
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216 | |
370f78d4 |
217 | Is a L<DBIx::Class::Storage::DBI::Replicated::Balancer> or derived class. This |
218 | is a class that takes a pool (L<DBIx::Class::Storage::DBI::Replicated::Pool>) |
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219 | |
26ab719a |
220 | =cut |
2bf79155 |
221 | |
26ab719a |
222 | has 'balancer' => ( |
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223 | is=>'rw', |
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224 | isa=>'DBIx::Class::Storage::DBI::Replicated::Balancer', |
225 | lazy_build=>1, |
226 | handles=>[qw/auto_validate_every/], |
26ab719a |
227 | ); |
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228 | |
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229 | =head2 master |
230 | |
231 | The master defines the canonical state for a pool of connected databases. All |
232 | the replicants are expected to match this databases state. Thus, in a classic |
233 | Master / Slaves distributed system, all the slaves are expected to replicate |
234 | the Master's state as quick as possible. This is the only database in the |
235 | pool of databases that is allowed to handle write traffic. |
236 | |
237 | =cut |
238 | |
239 | has 'master' => ( |
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240 | is=> 'ro', |
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241 | isa=>DBICStorageDBI, |
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242 | lazy_build=>1, |
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243 | ); |
244 | |
cb6ec758 |
245 | =head1 ATTRIBUTES IMPLEMENTING THE DBIx::Storage::DBI INTERFACE |
246 | |
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247 | The following methods are delegated all the methods required for the |
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248 | L<DBIx::Class::Storage::DBI> interface. |
249 | |
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250 | =cut |
251 | |
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252 | my $method_dispatch = { |
253 | writer => [qw/ |
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254 | on_connect_do |
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255 | on_disconnect_do |
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256 | on_connect_call |
257 | on_disconnect_call |
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258 | connect_info |
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259 | _connect_info |
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260 | throw_exception |
261 | sql_maker |
262 | sqlt_type |
263 | create_ddl_dir |
264 | deployment_statements |
265 | datetime_parser |
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266 | datetime_parser_type |
267 | build_datetime_parser |
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268 | last_insert_id |
269 | insert |
64cdad22 |
270 | update |
271 | delete |
272 | dbh |
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273 | txn_begin |
64cdad22 |
274 | txn_do |
275 | txn_commit |
276 | txn_rollback |
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277 | txn_scope_guard |
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278 | _exec_txn_rollback |
279 | _exec_txn_begin |
280 | _exec_txn_commit |
64cdad22 |
281 | deploy |
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282 | with_deferred_fk_checks |
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283 | dbh_do |
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284 | _prep_for_execute |
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285 | is_datatype_numeric |
286 | _count_select |
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287 | svp_rollback |
288 | svp_begin |
289 | svp_release |
e398f77e |
290 | relname_to_table_alias |
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291 | _dbh_last_insert_id |
3244fdcc |
292 | _default_dbi_connect_attributes |
293 | _dbi_connect_info |
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294 | _dbic_connect_attributes |
3244fdcc |
295 | auto_savepoint |
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296 | _query_start |
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297 | _query_end |
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298 | _format_for_trace |
299 | _dbi_attrs_for_bind |
3244fdcc |
300 | bind_attribute_by_data_type |
301 | transaction_depth |
302 | _dbh |
303 | _select_args |
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304 | _dbh_execute_for_fetch |
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305 | _sql_maker |
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306 | _dbh_execute_inserts_with_no_binds |
307 | _select_args_to_query |
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308 | _gen_sql_bind |
3244fdcc |
309 | _svp_generate_name |
3244fdcc |
310 | _normalize_connect_info |
311 | _parse_connect_do |
3244fdcc |
312 | savepoints |
3244fdcc |
313 | _sql_maker_opts |
314 | _conn_pid |
3244fdcc |
315 | _dbh_autocommit |
316 | _native_data_type |
317 | _get_dbh |
318 | sql_maker_class |
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319 | insert_bulk |
320 | _insert_bulk |
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321 | _execute |
322 | _do_query |
3244fdcc |
323 | _dbh_execute |
5b4f3fd0 |
324 | /, Class::MOP::Class->initialize('DBIx::Class::Storage::DBIHacks')->get_method_list ], |
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325 | reader => [qw/ |
326 | select |
327 | select_single |
328 | columns_info_for |
329 | _dbh_columns_info_for |
330 | _select |
331 | /], |
332 | unimplemented => [qw/ |
333 | _arm_global_destructor |
334 | _verify_pid |
335 | |
336 | get_use_dbms_capability |
337 | set_use_dbms_capability |
338 | get_dbms_capability |
339 | set_dbms_capability |
340 | _dbh_details |
341 | _dbh_get_info |
342 | |
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343 | _determine_connector_driver |
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344 | _extract_driver_from_connect_info |
75d3bdb2 |
345 | _describe_connection |
346 | _warn_undetermined_driver |
347 | |
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348 | sql_limit_dialect |
349 | sql_quote_char |
350 | sql_name_sep |
351 | |
4bea1fe7 |
352 | _prefetch_autovalues |
fabbd5cc |
353 | _perform_autoinc_retrieval |
354 | _autoinc_supplied_for_op |
4bea1fe7 |
355 | |
eec07bca |
356 | _resolve_bindattrs |
357 | |
4bea1fe7 |
358 | _max_column_bytesize |
359 | _is_lob_type |
360 | _is_binary_lob_type |
5efba7fc |
361 | _is_binary_type |
4bea1fe7 |
362 | _is_text_lob_type |
402ac1c9 |
363 | |
9930caaf |
364 | _prepare_sth |
365 | _bind_sth_params |
4bea1fe7 |
366 | /,( |
367 | # the capability framework |
368 | # not sure if CMOP->initialize does evil things to DBIC::S::DBI, fix if a problem |
369 | grep |
370 | { $_ =~ /^ _ (?: use | supports | determine_supports ) _ /x } |
371 | ( Class::MOP::Class->initialize('DBIx::Class::Storage::DBI')->get_all_method_names ) |
372 | )], |
373 | }; |
374 | |
375 | if (DBIx::Class::_ENV_::DBICTEST) { |
376 | |
377 | my $seen; |
378 | for my $type (keys %$method_dispatch) { |
379 | for (@{$method_dispatch->{$type}}) { |
380 | push @{$seen->{$_}}, $type; |
381 | } |
382 | } |
cb6ec758 |
383 | |
4bea1fe7 |
384 | if (my @dupes = grep { @{$seen->{$_}} > 1 } keys %$seen) { |
385 | die(join "\n", '', |
386 | 'The following methods show up multiple times in ::Storage::DBI::Replicated handlers:', |
387 | (map { "$_: " . (join ', ', @{$seen->{$_}}) } sort @dupes), |
388 | '', |
389 | ); |
390 | } |
bbdda281 |
391 | |
4bea1fe7 |
392 | if (my @cant = grep { ! DBIx::Class::Storage::DBI->can($_) } keys %$seen) { |
393 | die(join "\n", '', |
394 | '::Storage::DBI::Replicated specifies handling of the following *NON EXISTING* ::Storage::DBI methods:', |
395 | @cant, |
396 | '', |
397 | ); |
398 | } |
399 | } |
bbdda281 |
400 | |
4bea1fe7 |
401 | for my $method (@{$method_dispatch->{unimplemented}}) { |
402 | __PACKAGE__->meta->add_method($method, sub { |
70c28808 |
403 | my $self = shift; |
e705f529 |
404 | $self->throw_exception("$method() must not be called on ".(blessed $self).' objects'); |
4bea1fe7 |
405 | }); |
406 | } |
31a8aaaf |
407 | |
4bea1fe7 |
408 | =head2 read_handler |
584ea6e4 |
409 | |
5529838f |
410 | Defines an object that implements the read side of L<DBIx::Class::Storage::DBI>. |
584ea6e4 |
411 | |
4bea1fe7 |
412 | =cut |
413 | |
414 | has 'read_handler' => ( |
415 | is=>'rw', |
416 | isa=>Object, |
417 | lazy_build=>1, |
418 | handles=>$method_dispatch->{reader}, |
e471ab87 |
419 | ); |
420 | |
4bea1fe7 |
421 | =head2 write_handler |
422 | |
5529838f |
423 | Defines an object that implements the write side of L<DBIx::Class::Storage::DBI>, |
4bea1fe7 |
424 | as well as methods that don't write or read that can be called on only one |
425 | storage, methods that return a C<$dbh>, and any methods that don't make sense to |
426 | run on a replicant. |
427 | |
428 | =cut |
429 | |
430 | has 'write_handler' => ( |
431 | is=>'ro', |
432 | isa=>Object, |
433 | lazy_build=>1, |
434 | handles=>$method_dispatch->{writer}, |
7f4433eb |
435 | ); |
436 | |
4bea1fe7 |
437 | |
6d766626 |
438 | |
b2e4d522 |
439 | has _master_connect_info_opts => |
440 | (is => 'rw', isa => HashRef, default => sub { {} }); |
441 | |
442 | =head2 around: connect_info |
443 | |
48580715 |
444 | Preserves master's C<connect_info> options (for merging with replicants.) |
445 | Also sets any Replicated-related options from connect_info, such as |
dcdf7b2c |
446 | C<pool_type>, C<pool_args>, C<balancer_type> and C<balancer_args>. |
b2e4d522 |
447 | |
448 | =cut |
449 | |
450 | around connect_info => sub { |
451 | my ($next, $self, $info, @extra) = @_; |
452 | |
1fccee7b |
453 | $self->throw_exception( |
454 | 'connect_info can not be retrieved from a replicated storage - ' |
455 | . 'accessor must be called on a specific pool instance' |
456 | ) unless defined $info; |
457 | |
282a9a4f |
458 | my $merge = Hash::Merge->new('LEFT_PRECEDENT'); |
e666c5fd |
459 | |
b2e4d522 |
460 | my %opts; |
461 | for my $arg (@$info) { |
462 | next unless (reftype($arg)||'') eq 'HASH'; |
e666c5fd |
463 | %opts = %{ $merge->merge($arg, \%opts) }; |
b2e4d522 |
464 | } |
b2e4d522 |
465 | delete $opts{dsn}; |
466 | |
dcdf7b2c |
467 | if (@opts{qw/pool_type pool_args/}) { |
468 | $self->pool_type(delete $opts{pool_type}) |
469 | if $opts{pool_type}; |
470 | |
b88b85e7 |
471 | $self->pool_args( |
e666c5fd |
472 | $merge->merge((delete $opts{pool_args} || {}), $self->pool_args) |
b88b85e7 |
473 | ); |
dcdf7b2c |
474 | |
64ae1667 |
475 | ## Since we possibly changed the pool_args, we need to clear the current |
476 | ## pool object so that next time it is used it will be rebuilt. |
477 | $self->clear_pool; |
dcdf7b2c |
478 | } |
479 | |
480 | if (@opts{qw/balancer_type balancer_args/}) { |
481 | $self->balancer_type(delete $opts{balancer_type}) |
482 | if $opts{balancer_type}; |
483 | |
b88b85e7 |
484 | $self->balancer_args( |
e666c5fd |
485 | $merge->merge((delete $opts{balancer_args} || {}), $self->balancer_args) |
b88b85e7 |
486 | ); |
dcdf7b2c |
487 | |
67c43863 |
488 | $self->balancer($self->_build_balancer) |
6f7344b8 |
489 | if $self->balancer; |
dcdf7b2c |
490 | } |
491 | |
b2e4d522 |
492 | $self->_master_connect_info_opts(\%opts); |
493 | |
1abccf54 |
494 | return preserve_context { |
495 | $self->$next($info, @extra); |
496 | } after => sub { |
497 | # Make sure master is blessed into the correct class and apply role to it. |
498 | my $master = $self->master; |
499 | $master->_determine_driver; |
500 | Moose::Meta::Class->initialize(ref $master); |
cea43436 |
501 | |
1abccf54 |
502 | DBIx::Class::Storage::DBI::Replicated::WithDSN->meta->apply($master); |
0ce2d0d5 |
503 | |
1abccf54 |
504 | # link pool back to master |
505 | $self->pool->master($master); |
506 | }; |
b2e4d522 |
507 | }; |
508 | |
26ab719a |
509 | =head1 METHODS |
2bf79155 |
510 | |
26ab719a |
511 | This class defines the following methods. |
2bf79155 |
512 | |
c354902c |
513 | =head2 BUILDARGS |
2bf79155 |
514 | |
faaba25f |
515 | L<DBIx::Class::Schema> when instantiating its storage passed itself as the |
2ce6e9a6 |
516 | first argument. So we need to massage the arguments a bit so that all the |
517 | bits get put into the correct places. |
2bf79155 |
518 | |
519 | =cut |
520 | |
c354902c |
521 | sub BUILDARGS { |
fd323bf1 |
522 | my ($class, $schema, $storage_type_args, @args) = @_; |
d4daee7b |
523 | |
c354902c |
524 | return { |
6f7344b8 |
525 | schema=>$schema, |
526 | %$storage_type_args, |
527 | @args |
c354902c |
528 | } |
529 | } |
2bf79155 |
530 | |
cb6ec758 |
531 | =head2 _build_master |
2bf79155 |
532 | |
cb6ec758 |
533 | Lazy builder for the L</master> attribute. |
2bf79155 |
534 | |
535 | =cut |
536 | |
cb6ec758 |
537 | sub _build_master { |
2ce6e9a6 |
538 | my $self = shift @_; |
ee356d00 |
539 | my $master = DBIx::Class::Storage::DBI->new($self->schema); |
ee356d00 |
540 | $master |
106d5f3b |
541 | } |
542 | |
26ab719a |
543 | =head2 _build_pool |
2bf79155 |
544 | |
26ab719a |
545 | Lazy builder for the L</pool> attribute. |
2bf79155 |
546 | |
547 | =cut |
548 | |
26ab719a |
549 | sub _build_pool { |
64cdad22 |
550 | my $self = shift @_; |
551 | $self->create_pool(%{$self->pool_args}); |
2bf79155 |
552 | } |
553 | |
26ab719a |
554 | =head2 _build_balancer |
2bf79155 |
555 | |
cb6ec758 |
556 | Lazy builder for the L</balancer> attribute. This takes a Pool object so that |
557 | the balancer knows which pool it's balancing. |
2bf79155 |
558 | |
559 | =cut |
560 | |
26ab719a |
561 | sub _build_balancer { |
64cdad22 |
562 | my $self = shift @_; |
563 | $self->create_balancer( |
6f7344b8 |
564 | pool=>$self->pool, |
64cdad22 |
565 | master=>$self->master, |
566 | %{$self->balancer_args}, |
567 | ); |
2bf79155 |
568 | } |
569 | |
cb6ec758 |
570 | =head2 _build_write_handler |
2bf79155 |
571 | |
cb6ec758 |
572 | Lazy builder for the L</write_handler> attribute. The default is to set this to |
573 | the L</master>. |
50336325 |
574 | |
575 | =cut |
576 | |
cb6ec758 |
577 | sub _build_write_handler { |
64cdad22 |
578 | return shift->master; |
cb6ec758 |
579 | } |
50336325 |
580 | |
cb6ec758 |
581 | =head2 _build_read_handler |
2bf79155 |
582 | |
cb6ec758 |
583 | Lazy builder for the L</read_handler> attribute. The default is to set this to |
584 | the L</balancer>. |
2bf79155 |
585 | |
586 | =cut |
587 | |
cb6ec758 |
588 | sub _build_read_handler { |
64cdad22 |
589 | return shift->balancer; |
cb6ec758 |
590 | } |
50336325 |
591 | |
cb6ec758 |
592 | =head2 around: connect_replicants |
2bf79155 |
593 | |
cb6ec758 |
594 | All calls to connect_replicants needs to have an existing $schema tacked onto |
5529838f |
595 | top of the args, since L<DBIx::Class::Storage::DBI> needs it, and any |
596 | L<connect_info|DBIx::Class::Storage::DBI/connect_info> |
b2e4d522 |
597 | options merged with the master, with replicant opts having higher priority. |
955a6df6 |
598 | |
cb6ec758 |
599 | =cut |
955a6df6 |
600 | |
b2e4d522 |
601 | around connect_replicants => sub { |
602 | my ($next, $self, @args) = @_; |
603 | |
604 | for my $r (@args) { |
605 | $r = [ $r ] unless reftype $r eq 'ARRAY'; |
606 | |
1a58752c |
607 | $self->throw_exception('coderef replicant connect_info not supported') |
b2e4d522 |
608 | if ref $r->[0] && reftype $r->[0] eq 'CODE'; |
609 | |
610 | # any connect_info options? |
611 | my $i = 0; |
612 | $i++ while $i < @$r && (reftype($r->[$i])||'') ne 'HASH'; |
613 | |
6f7344b8 |
614 | # make one if none |
b2e4d522 |
615 | $r->[$i] = {} unless $r->[$i]; |
616 | |
617 | # merge if two hashes |
b88b85e7 |
618 | my @hashes = @$r[$i .. $#{$r}]; |
619 | |
1a58752c |
620 | $self->throw_exception('invalid connect_info options') |
b88b85e7 |
621 | if (grep { reftype($_) eq 'HASH' } @hashes) != @hashes; |
622 | |
1a58752c |
623 | $self->throw_exception('too many hashrefs in connect_info') |
b88b85e7 |
624 | if @hashes > 2; |
625 | |
282a9a4f |
626 | my $merge = Hash::Merge->new('LEFT_PRECEDENT'); |
e666c5fd |
627 | my %opts = %{ $merge->merge(reverse @hashes) }; |
b88b85e7 |
628 | |
629 | # delete them |
b2e4d522 |
630 | splice @$r, $i+1, ($#{$r} - $i), (); |
631 | |
0bd8e058 |
632 | # make sure master/replicants opts don't clash |
633 | my %master_opts = %{ $self->_master_connect_info_opts }; |
634 | if (exists $opts{dbh_maker}) { |
635 | delete @master_opts{qw/dsn user password/}; |
636 | } |
637 | delete $master_opts{dbh_maker}; |
638 | |
b2e4d522 |
639 | # merge with master |
e666c5fd |
640 | %opts = %{ $merge->merge(\%opts, \%master_opts) }; |
b2e4d522 |
641 | |
642 | # update |
643 | $r->[$i] = \%opts; |
644 | } |
645 | |
646 | $self->$next($self->schema, @args); |
955a6df6 |
647 | }; |
2bf79155 |
648 | |
2bf79155 |
649 | =head2 all_storages |
650 | |
4a0eed52 |
651 | Returns an array of all the connected storage backends. The first element |
652 | in the returned array is the master, and the rest are each of the |
2bf79155 |
653 | replicants. |
654 | |
655 | =cut |
656 | |
657 | sub all_storages { |
64cdad22 |
658 | my $self = shift @_; |
659 | return grep {defined $_ && blessed $_} ( |
660 | $self->master, |
6412a592 |
661 | values %{ $self->replicants }, |
64cdad22 |
662 | ); |
2bf79155 |
663 | } |
664 | |
c4d3fae2 |
665 | =head2 execute_reliably ($coderef, ?@args) |
666 | |
667 | Given a coderef, saves the current state of the L</read_handler>, forces it to |
48580715 |
668 | use reliable storage (e.g. sets it to the master), executes a coderef and then |
c4d3fae2 |
669 | restores the original state. |
670 | |
671 | Example: |
672 | |
64cdad22 |
673 | my $reliably = sub { |
674 | my $name = shift @_; |
675 | $schema->resultset('User')->create({name=>$name}); |
fd323bf1 |
676 | my $user_rs = $schema->resultset('User')->find({name=>$name}); |
64cdad22 |
677 | return $user_rs; |
678 | }; |
c4d3fae2 |
679 | |
64cdad22 |
680 | my $user_rs = $schema->storage->execute_reliably($reliably, 'John'); |
c4d3fae2 |
681 | |
682 | Use this when you must be certain of your database state, such as when you just |
683 | inserted something and need to get a resultset including it, etc. |
684 | |
685 | =cut |
686 | |
687 | sub execute_reliably { |
1abccf54 |
688 | my $self = shift; |
689 | my $coderef = shift; |
d4daee7b |
690 | |
64cdad22 |
691 | unless( ref $coderef eq 'CODE') { |
692 | $self->throw_exception('Second argument must be a coderef'); |
693 | } |
d4daee7b |
694 | |
1abccf54 |
695 | ## replace the current read handler for the remainder of the scope |
696 | local $self->{read_handler} = $self->master; |
d4daee7b |
697 | |
1abccf54 |
698 | my $args = \@_; |
699 | return try { |
700 | $coderef->(@$args); |
ed7ab0f4 |
701 | } catch { |
702 | $self->throw_exception("coderef returned an error: $_"); |
64cdad22 |
703 | }; |
c4d3fae2 |
704 | } |
705 | |
cb6ec758 |
706 | =head2 set_reliable_storage |
707 | |
708 | Sets the current $schema to be 'reliable', that is all queries, both read and |
709 | write are sent to the master |
d4daee7b |
710 | |
cb6ec758 |
711 | =cut |
712 | |
713 | sub set_reliable_storage { |
64cdad22 |
714 | my $self = shift @_; |
715 | my $schema = $self->schema; |
716 | my $write_handler = $self->schema->storage->write_handler; |
d4daee7b |
717 | |
64cdad22 |
718 | $schema->storage->read_handler($write_handler); |
cb6ec758 |
719 | } |
720 | |
721 | =head2 set_balanced_storage |
722 | |
723 | Sets the current $schema to be use the </balancer> for all reads, while all |
48580715 |
724 | writes are sent to the master only |
d4daee7b |
725 | |
cb6ec758 |
726 | =cut |
727 | |
728 | sub set_balanced_storage { |
64cdad22 |
729 | my $self = shift @_; |
730 | my $schema = $self->schema; |
bd5da369 |
731 | my $balanced_handler = $self->schema->storage->balancer; |
d4daee7b |
732 | |
bd5da369 |
733 | $schema->storage->read_handler($balanced_handler); |
cb6ec758 |
734 | } |
2bf79155 |
735 | |
736 | =head2 connected |
737 | |
738 | Check that the master and at least one of the replicants is connected. |
739 | |
740 | =cut |
741 | |
742 | sub connected { |
64cdad22 |
743 | my $self = shift @_; |
744 | return |
745 | $self->master->connected && |
746 | $self->pool->connected_replicants; |
2bf79155 |
747 | } |
748 | |
2bf79155 |
749 | =head2 ensure_connected |
750 | |
751 | Make sure all the storages are connected. |
752 | |
753 | =cut |
754 | |
755 | sub ensure_connected { |
64cdad22 |
756 | my $self = shift @_; |
757 | foreach my $source ($self->all_storages) { |
758 | $source->ensure_connected(@_); |
759 | } |
2bf79155 |
760 | } |
761 | |
2bf79155 |
762 | =head2 limit_dialect |
763 | |
764 | Set the limit_dialect for all existing storages |
765 | |
766 | =cut |
767 | |
768 | sub limit_dialect { |
64cdad22 |
769 | my $self = shift @_; |
770 | foreach my $source ($self->all_storages) { |
771 | $source->limit_dialect(@_); |
772 | } |
f3e9f010 |
773 | return $self->master->limit_dialect; |
2bf79155 |
774 | } |
775 | |
2bf79155 |
776 | =head2 quote_char |
777 | |
778 | Set the quote_char for all existing storages |
779 | |
780 | =cut |
781 | |
782 | sub quote_char { |
64cdad22 |
783 | my $self = shift @_; |
784 | foreach my $source ($self->all_storages) { |
785 | $source->quote_char(@_); |
786 | } |
3fbe08e3 |
787 | return $self->master->quote_char; |
2bf79155 |
788 | } |
789 | |
2bf79155 |
790 | =head2 name_sep |
791 | |
792 | Set the name_sep for all existing storages |
793 | |
794 | =cut |
795 | |
796 | sub name_sep { |
64cdad22 |
797 | my $self = shift @_; |
798 | foreach my $source ($self->all_storages) { |
799 | $source->name_sep(@_); |
800 | } |
3fbe08e3 |
801 | return $self->master->name_sep; |
2bf79155 |
802 | } |
803 | |
2bf79155 |
804 | =head2 set_schema |
805 | |
806 | Set the schema object for all existing storages |
807 | |
808 | =cut |
809 | |
810 | sub set_schema { |
64cdad22 |
811 | my $self = shift @_; |
812 | foreach my $source ($self->all_storages) { |
813 | $source->set_schema(@_); |
814 | } |
2bf79155 |
815 | } |
816 | |
2bf79155 |
817 | =head2 debug |
818 | |
819 | set a debug flag across all storages |
820 | |
821 | =cut |
822 | |
823 | sub debug { |
64cdad22 |
824 | my $self = shift @_; |
3fbe08e3 |
825 | if(@_) { |
826 | foreach my $source ($self->all_storages) { |
827 | $source->debug(@_); |
6f7344b8 |
828 | } |
64cdad22 |
829 | } |
3fbe08e3 |
830 | return $self->master->debug; |
2bf79155 |
831 | } |
832 | |
2bf79155 |
833 | =head2 debugobj |
834 | |
cea43436 |
835 | set a debug object |
2bf79155 |
836 | |
837 | =cut |
838 | |
839 | sub debugobj { |
64cdad22 |
840 | my $self = shift @_; |
cea43436 |
841 | return $self->master->debugobj(@_); |
2bf79155 |
842 | } |
843 | |
2bf79155 |
844 | =head2 debugfh |
845 | |
cea43436 |
846 | set a debugfh object |
2bf79155 |
847 | |
848 | =cut |
849 | |
850 | sub debugfh { |
64cdad22 |
851 | my $self = shift @_; |
cea43436 |
852 | return $self->master->debugfh(@_); |
2bf79155 |
853 | } |
854 | |
2bf79155 |
855 | =head2 debugcb |
856 | |
cea43436 |
857 | set a debug callback |
2bf79155 |
858 | |
859 | =cut |
860 | |
861 | sub debugcb { |
64cdad22 |
862 | my $self = shift @_; |
cea43436 |
863 | return $self->master->debugcb(@_); |
2bf79155 |
864 | } |
865 | |
2bf79155 |
866 | =head2 disconnect |
867 | |
868 | disconnect everything |
869 | |
870 | =cut |
871 | |
872 | sub disconnect { |
64cdad22 |
873 | my $self = shift @_; |
874 | foreach my $source ($self->all_storages) { |
875 | $source->disconnect(@_); |
876 | } |
2bf79155 |
877 | } |
878 | |
b2e4d522 |
879 | =head2 cursor_class |
880 | |
881 | set cursor class on all storages, or return master's |
882 | |
883 | =cut |
884 | |
885 | sub cursor_class { |
886 | my ($self, $cursor_class) = @_; |
887 | |
888 | if ($cursor_class) { |
889 | $_->cursor_class($cursor_class) for $self->all_storages; |
890 | } |
891 | $self->master->cursor_class; |
892 | } |
d4daee7b |
893 | |
3244fdcc |
894 | =head2 cursor |
895 | |
896 | set cursor class on all storages, or return master's, alias for L</cursor_class> |
897 | above. |
898 | |
899 | =cut |
900 | |
901 | sub cursor { |
902 | my ($self, $cursor_class) = @_; |
903 | |
904 | if ($cursor_class) { |
905 | $_->cursor($cursor_class) for $self->all_storages; |
906 | } |
907 | $self->master->cursor; |
908 | } |
909 | |
910 | =head2 unsafe |
911 | |
912 | sets the L<DBIx::Class::Storage::DBI/unsafe> option on all storages or returns |
913 | master's current setting |
914 | |
915 | =cut |
916 | |
917 | sub unsafe { |
918 | my $self = shift; |
919 | |
920 | if (@_) { |
921 | $_->unsafe(@_) for $self->all_storages; |
922 | } |
923 | |
924 | return $self->master->unsafe; |
925 | } |
926 | |
927 | =head2 disable_sth_caching |
928 | |
929 | sets the L<DBIx::Class::Storage::DBI/disable_sth_caching> option on all storages |
930 | or returns master's current setting |
931 | |
932 | =cut |
933 | |
934 | sub disable_sth_caching { |
935 | my $self = shift; |
936 | |
937 | if (@_) { |
938 | $_->disable_sth_caching(@_) for $self->all_storages; |
939 | } |
940 | |
941 | return $self->master->disable_sth_caching; |
942 | } |
943 | |
944 | =head2 lag_behind_master |
945 | |
946 | returns the highest Replicant L<DBIx::Class::Storage::DBI/lag_behind_master> |
947 | setting |
948 | |
949 | =cut |
950 | |
951 | sub lag_behind_master { |
952 | my $self = shift; |
953 | |
954 | return max map $_->lag_behind_master, $self->replicants; |
fd323bf1 |
955 | } |
3244fdcc |
956 | |
957 | =head2 is_replicating |
958 | |
959 | returns true if all replicants return true for |
960 | L<DBIx::Class::Storage::DBI/is_replicating> |
961 | |
962 | =cut |
963 | |
964 | sub is_replicating { |
965 | my $self = shift; |
966 | |
967 | return (grep $_->is_replicating, $self->replicants) == ($self->replicants); |
968 | } |
969 | |
970 | =head2 connect_call_datetime_setup |
971 | |
972 | calls L<DBIx::Class::Storage::DBI/connect_call_datetime_setup> for all storages |
973 | |
974 | =cut |
975 | |
976 | sub connect_call_datetime_setup { |
977 | my $self = shift; |
978 | $_->connect_call_datetime_setup for $self->all_storages; |
979 | } |
980 | |
981 | sub _populate_dbh { |
982 | my $self = shift; |
983 | $_->_populate_dbh for $self->all_storages; |
984 | } |
985 | |
986 | sub _connect { |
987 | my $self = shift; |
988 | $_->_connect for $self->all_storages; |
989 | } |
990 | |
991 | sub _rebless { |
992 | my $self = shift; |
993 | $_->_rebless for $self->all_storages; |
994 | } |
995 | |
996 | sub _determine_driver { |
997 | my $self = shift; |
998 | $_->_determine_driver for $self->all_storages; |
999 | } |
1000 | |
1001 | sub _driver_determined { |
1002 | my $self = shift; |
fd323bf1 |
1003 | |
3244fdcc |
1004 | if (@_) { |
1005 | $_->_driver_determined(@_) for $self->all_storages; |
1006 | } |
1007 | |
1008 | return $self->master->_driver_determined; |
1009 | } |
1010 | |
1011 | sub _init { |
1012 | my $self = shift; |
fd323bf1 |
1013 | |
3244fdcc |
1014 | $_->_init for $self->all_storages; |
1015 | } |
1016 | |
1017 | sub _run_connection_actions { |
1018 | my $self = shift; |
fd323bf1 |
1019 | |
3244fdcc |
1020 | $_->_run_connection_actions for $self->all_storages; |
1021 | } |
1022 | |
1023 | sub _do_connection_actions { |
1024 | my $self = shift; |
fd323bf1 |
1025 | |
3244fdcc |
1026 | if (@_) { |
1027 | $_->_do_connection_actions(@_) for $self->all_storages; |
1028 | } |
1029 | } |
1030 | |
1031 | sub connect_call_do_sql { |
1032 | my $self = shift; |
1033 | $_->connect_call_do_sql(@_) for $self->all_storages; |
1034 | } |
1035 | |
1036 | sub disconnect_call_do_sql { |
1037 | my $self = shift; |
1038 | $_->disconnect_call_do_sql(@_) for $self->all_storages; |
1039 | } |
1040 | |
1041 | sub _seems_connected { |
1042 | my $self = shift; |
1043 | |
1044 | return min map $_->_seems_connected, $self->all_storages; |
1045 | } |
1046 | |
1047 | sub _ping { |
1048 | my $self = shift; |
1049 | |
1050 | return min map $_->_ping, $self->all_storages; |
1051 | } |
1052 | |
bbdda281 |
1053 | # not using the normalized_version, because we want to preserve |
1054 | # version numbers much longer than the conventional xxx.yyyzzz |
7da56142 |
1055 | my $numify_ver = sub { |
1056 | my $ver = shift; |
1057 | my @numparts = split /\D+/, $ver; |
bbdda281 |
1058 | my $format = '%d.' . (join '', ('%06d') x (@numparts - 1)); |
7da56142 |
1059 | |
1060 | return sprintf $format, @numparts; |
1061 | }; |
fecb38cb |
1062 | sub _server_info { |
1063 | my $self = shift; |
1064 | |
bbdda281 |
1065 | if (not $self->_dbh_details->{info}) { |
1066 | $self->_dbh_details->{info} = ( |
fd323bf1 |
1067 | reduce { $a->[0] < $b->[0] ? $a : $b } |
7da56142 |
1068 | map [ $numify_ver->($_->{dbms_version}), $_ ], |
1069 | map $_->_server_info, $self->all_storages |
1070 | )->[1]; |
fecb38cb |
1071 | } |
1072 | |
bbdda281 |
1073 | return $self->next::method; |
fecb38cb |
1074 | } |
1075 | |
1076 | sub _get_server_version { |
1077 | my $self = shift; |
1078 | |
1079 | return $self->_server_info->{dbms_version}; |
1080 | } |
1081 | |
7e38d850 |
1082 | =head1 GOTCHAS |
1083 | |
1084 | Due to the fact that replicants can lag behind a master, you must take care to |
1085 | make sure you use one of the methods to force read queries to a master should |
1086 | you need realtime data integrity. For example, if you insert a row, and then |
3dd506b8 |
1087 | immediately re-read it from the database (say, by doing |
1088 | L<< $result->discard_changes|DBIx::Class::Row/discard_changes >>) |
7e38d850 |
1089 | or you insert a row and then immediately build a query that expects that row |
1090 | to be an item, you should force the master to handle reads. Otherwise, due to |
1091 | the lag, there is no certainty your data will be in the expected state. |
1092 | |
1093 | For data integrity, all transactions automatically use the master storage for |
1094 | all read and write queries. Using a transaction is the preferred and recommended |
1095 | method to force the master to handle all read queries. |
1096 | |
1097 | Otherwise, you can force a single query to use the master with the 'force_pool' |
1098 | attribute: |
1099 | |
47d7b769 |
1100 | my $result = $resultset->search(undef, {force_pool=>'master'})->find($pk); |
7e38d850 |
1101 | |
b1de1b06 |
1102 | This attribute will safely be ignored by non replicated storages, so you can use |
7e38d850 |
1103 | the same code for both types of systems. |
1104 | |
1105 | Lastly, you can use the L</execute_reliably> method, which works very much like |
1106 | a transaction. |
1107 | |
1108 | For debugging, you can turn replication on/off with the methods L</set_reliable_storage> |
1109 | and L</set_balanced_storage>, however this operates at a global level and is not |
1110 | suitable if you have a shared Schema object being used by multiple processes, |
1111 | such as on a web application server. You can get around this limitation by |
1112 | using the Schema clone method. |
1113 | |
1114 | my $new_schema = $schema->clone; |
1115 | $new_schema->set_reliable_storage; |
d4daee7b |
1116 | |
7e38d850 |
1117 | ## $new_schema will use only the Master storage for all reads/writes while |
1118 | ## the $schema object will use replicated storage. |
1119 | |
a2bd3796 |
1120 | =head1 FURTHER QUESTIONS? |
f5d3a5de |
1121 | |
a2bd3796 |
1122 | Check the list of L<additional DBIC resources|DBIx::Class/GETTING HELP/SUPPORT>. |
2156bbdd |
1123 | |
a2bd3796 |
1124 | =head1 COPYRIGHT AND LICENSE |
f5d3a5de |
1125 | |
a2bd3796 |
1126 | This module is free software L<copyright|DBIx::Class/COPYRIGHT AND LICENSE> |
1127 | by the L<DBIx::Class (DBIC) authors|DBIx::Class/AUTHORS>. You can |
1128 | redistribute it and/or modify it under the same terms as the |
1129 | L<DBIx::Class library|DBIx::Class/COPYRIGHT AND LICENSE>. |
f5d3a5de |
1130 | |
1131 | =cut |
1132 | |
c354902c |
1133 | __PACKAGE__->meta->make_immutable; |
1134 | |
f5d3a5de |
1135 | 1; |