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1 | package DBIx::Class::Storage::DBI::Replicated; |
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2 | |
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3 | BEGIN { |
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4 | use DBIx::Class; |
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5 | die('The following modules are required for Replication ' . DBIx::Class::Optional::Dependencies->req_missing_for ('replicated') . "\n" ) |
a34b0c89 |
6 | unless DBIx::Class::Optional::Dependencies->req_ok_for ('replicated'); |
ecb65397 |
7 | } |
8 | |
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9 | use Moose; |
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10 | use DBIx::Class::Storage::DBI; |
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11 | use DBIx::Class::Storage::DBI::Replicated::Pool; |
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12 | use DBIx::Class::Storage::DBI::Replicated::Balancer; |
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13 | use DBIx::Class::Storage::DBI::Replicated::Types qw/BalancerClassNamePart DBICSchema DBICStorageDBI/; |
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14 | use MooseX::Types::Moose qw/ClassName HashRef Object/; |
b2e4d522 |
15 | use Scalar::Util 'reftype'; |
e666c5fd |
16 | use Hash::Merge; |
7da56142 |
17 | use List::Util qw/min max reduce/; |
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18 | use Context::Preserve 'preserve_context'; |
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19 | use Try::Tiny; |
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20 | |
21 | use namespace::clean -except => 'meta'; |
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22 | |
23 | =head1 NAME |
24 | |
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25 | DBIx::Class::Storage::DBI::Replicated - BETA Replicated database support |
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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 |
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31 | tasks. |
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32 | |
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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 |
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35 | that the Pool object should get. |
36 | |
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37 | my $schema = Schema::Class->clone; |
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38 | $schema->storage_type( ['::DBI::Replicated', {balancer=>'::Random'}] ); |
ce854fd3 |
39 | $schema->connection(...); |
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40 | |
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41 | Next, you need to add in the Replicants. Basically this is an array of |
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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. |
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44 | |
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45 | $schema->storage->connect_replicants( |
46 | [$dsn1, $user, $pass, \%opts], |
47 | [$dsn2, $user, $pass, \%opts], |
48 | [$dsn3, $user, $pass, \%opts], |
49 | ); |
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50 | |
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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'}); |
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55 | |
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56 | You can force a given query to use a particular storage using the search |
57 | attribute 'force_pool'. For example: |
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58 | |
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59 | my $rs = $schema->resultset('Source')->search(undef, {force_pool=>'master'}); |
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60 | |
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61 | Now $rs will force everything (both reads and writes) to use whatever was setup |
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62 | as the master storage. 'master' is hardcoded to always point to the Master, |
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63 | but you can also use any Replicant name. Please see: |
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64 | L<DBIx::Class::Storage::DBI::Replicated::Pool> and the replicants attribute for more. |
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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. |
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70 | |
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71 | If you have a multi-statement read only transaction you can force it to select |
72 | a random server in the pool by: |
73 | |
74 | my $rs = $schema->resultset('Source')->search( undef, |
75 | { force_pool => $db->storage->read_handler->next_storage } |
76 | ); |
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77 | |
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78 | =head1 DESCRIPTION |
79 | |
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80 | Warning: This class is marked BETA. This has been running a production |
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81 | website using MySQL native replication as its backend and we have some decent |
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82 | test coverage but the code hasn't yet been stressed by a variety of databases. |
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83 | Individual DBs may have quirks we are not aware of. Please use this in first |
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84 | development and pass along your experiences/bug fixes. |
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85 | |
86 | This class implements replicated data store for DBI. Currently you can define |
87 | one master and numerous slave database connections. All write-type queries |
88 | (INSERT, UPDATE, DELETE and even LAST_INSERT_ID) are routed to master |
89 | database, all read-type queries (SELECTs) go to the slave database. |
90 | |
91 | Basically, any method request that L<DBIx::Class::Storage::DBI> would normally |
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92 | handle gets delegated to one of the two attributes: L</read_handler> or to |
93 | L</write_handler>. Additionally, some methods need to be distributed |
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94 | to all existing storages. This way our storage class is a drop in replacement |
95 | for L<DBIx::Class::Storage::DBI>. |
96 | |
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97 | Read traffic is spread across the replicants (slaves) occurring to a user |
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98 | selected algorithm. The default algorithm is random weighted. |
99 | |
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100 | =head1 NOTES |
101 | |
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102 | The consistency between master and replicants is database specific. The Pool |
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103 | gives you a method to validate its replicants, removing and replacing them |
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104 | when they fail/pass predefined criteria. Please make careful use of the ways |
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105 | to force a query to run against Master when needed. |
106 | |
107 | =head1 REQUIREMENTS |
108 | |
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109 | Replicated Storage has additional requirements not currently part of |
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110 | L<DBIx::Class>. See L<DBIx::Class::Optional::Dependencies> for more details. |
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111 | |
112 | =head1 ATTRIBUTES |
113 | |
114 | This class defines the following attributes. |
115 | |
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116 | =head2 schema |
117 | |
118 | The underlying L<DBIx::Class::Schema> object this storage is attaching |
119 | |
120 | =cut |
121 | |
122 | has 'schema' => ( |
123 | is=>'rw', |
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124 | isa=>DBICSchema, |
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125 | weak_ref=>1, |
126 | required=>1, |
127 | ); |
128 | |
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129 | =head2 pool_type |
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130 | |
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131 | Contains the classname which will instantiate the L</pool> object. Defaults |
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132 | to: L<DBIx::Class::Storage::DBI::Replicated::Pool>. |
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133 | |
134 | =cut |
135 | |
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136 | has 'pool_type' => ( |
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137 | is=>'rw', |
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138 | isa=>ClassName, |
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139 | default=>'DBIx::Class::Storage::DBI::Replicated::Pool', |
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140 | handles=>{ |
141 | 'create_pool' => 'new', |
142 | }, |
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143 | ); |
144 | |
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145 | =head2 pool_args |
146 | |
147 | Contains a hashref of initialized information to pass to the Balancer object. |
212cc5c2 |
148 | See L<DBIx::Class::Storage::DBI::Replicated::Pool> for available arguments. |
f068a139 |
149 | |
150 | =cut |
151 | |
152 | has 'pool_args' => ( |
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153 | is=>'rw', |
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154 | isa=>HashRef, |
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155 | lazy=>1, |
64cdad22 |
156 | default=>sub { {} }, |
f068a139 |
157 | ); |
158 | |
159 | |
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160 | =head2 balancer_type |
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161 | |
162 | The replication pool requires a balance class to provider the methods for |
163 | choose how to spread the query load across each replicant in the pool. |
164 | |
165 | =cut |
166 | |
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167 | has 'balancer_type' => ( |
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168 | is=>'rw', |
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169 | isa=>BalancerClassNamePart, |
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170 | coerce=>1, |
171 | required=>1, |
172 | default=> 'DBIx::Class::Storage::DBI::Replicated::Balancer::First', |
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173 | handles=>{ |
174 | 'create_balancer' => 'new', |
175 | }, |
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176 | ); |
177 | |
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178 | =head2 balancer_args |
179 | |
180 | Contains a hashref of initialized information to pass to the Balancer object. |
212cc5c2 |
181 | See L<DBIx::Class::Storage::DBI::Replicated::Balancer> for available arguments. |
17b05c13 |
182 | |
183 | =cut |
184 | |
185 | has 'balancer_args' => ( |
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186 | is=>'rw', |
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187 | isa=>HashRef, |
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188 | lazy=>1, |
189 | required=>1, |
190 | default=>sub { {} }, |
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191 | ); |
192 | |
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193 | =head2 pool |
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194 | |
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195 | Is a L<DBIx::Class::Storage::DBI::Replicated::Pool> or derived class. This is a |
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196 | container class for one or more replicated databases. |
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197 | |
198 | =cut |
199 | |
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200 | has 'pool' => ( |
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201 | is=>'ro', |
202 | isa=>'DBIx::Class::Storage::DBI::Replicated::Pool', |
203 | lazy_build=>1, |
204 | handles=>[qw/ |
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205 | connect_replicants |
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206 | replicants |
207 | has_replicants |
208 | /], |
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209 | ); |
210 | |
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211 | =head2 balancer |
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212 | |
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213 | Is a L<DBIx::Class::Storage::DBI::Replicated::Balancer> or derived class. This |
214 | is a class that takes a pool (L<DBIx::Class::Storage::DBI::Replicated::Pool>) |
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215 | |
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216 | =cut |
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217 | |
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218 | has 'balancer' => ( |
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219 | is=>'rw', |
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220 | isa=>'DBIx::Class::Storage::DBI::Replicated::Balancer', |
221 | lazy_build=>1, |
222 | handles=>[qw/auto_validate_every/], |
26ab719a |
223 | ); |
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224 | |
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225 | =head2 master |
226 | |
227 | The master defines the canonical state for a pool of connected databases. All |
228 | the replicants are expected to match this databases state. Thus, in a classic |
229 | Master / Slaves distributed system, all the slaves are expected to replicate |
230 | the Master's state as quick as possible. This is the only database in the |
231 | pool of databases that is allowed to handle write traffic. |
232 | |
233 | =cut |
234 | |
235 | has 'master' => ( |
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236 | is=> 'ro', |
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237 | isa=>DBICStorageDBI, |
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238 | lazy_build=>1, |
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239 | ); |
240 | |
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241 | =head1 ATTRIBUTES IMPLEMENTING THE DBIx::Storage::DBI INTERFACE |
242 | |
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243 | The following methods are delegated all the methods required for the |
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244 | L<DBIx::Class::Storage::DBI> interface. |
245 | |
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246 | =cut |
247 | |
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248 | my $method_dispatch = { |
249 | writer => [qw/ |
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250 | on_connect_do |
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251 | on_disconnect_do |
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252 | on_connect_call |
253 | on_disconnect_call |
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254 | connect_info |
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255 | _connect_info |
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256 | throw_exception |
257 | sql_maker |
258 | sqlt_type |
259 | create_ddl_dir |
260 | deployment_statements |
261 | datetime_parser |
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262 | datetime_parser_type |
263 | build_datetime_parser |
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264 | last_insert_id |
265 | insert |
266 | insert_bulk |
267 | update |
268 | delete |
269 | dbh |
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270 | txn_begin |
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271 | txn_do |
272 | txn_commit |
273 | txn_rollback |
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274 | txn_scope_guard |
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275 | _exec_txn_rollback |
276 | _exec_txn_begin |
277 | _exec_txn_commit |
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278 | deploy |
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279 | with_deferred_fk_checks |
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280 | dbh_do |
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281 | _prep_for_execute |
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282 | is_datatype_numeric |
283 | _count_select |
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284 | svp_rollback |
285 | svp_begin |
286 | svp_release |
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287 | relname_to_table_alias |
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288 | _dbh_last_insert_id |
3244fdcc |
289 | _default_dbi_connect_attributes |
290 | _dbi_connect_info |
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291 | _dbic_connect_attributes |
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292 | auto_savepoint |
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293 | _query_start |
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294 | _query_end |
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295 | _format_for_trace |
296 | _dbi_attrs_for_bind |
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297 | bind_attribute_by_data_type |
298 | transaction_depth |
299 | _dbh |
300 | _select_args |
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301 | _dbh_execute_for_fetch |
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302 | _sql_maker |
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303 | _dbh_execute_inserts_with_no_binds |
304 | _select_args_to_query |
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305 | _gen_sql_bind |
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306 | _svp_generate_name |
3244fdcc |
307 | _normalize_connect_info |
308 | _parse_connect_do |
3244fdcc |
309 | savepoints |
3244fdcc |
310 | _sql_maker_opts |
311 | _conn_pid |
3244fdcc |
312 | _dbh_autocommit |
313 | _native_data_type |
314 | _get_dbh |
315 | sql_maker_class |
3244fdcc |
316 | _execute |
317 | _do_query |
402ac1c9 |
318 | _sth |
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319 | _dbh_sth |
320 | _dbh_execute |
5b4f3fd0 |
321 | /, Class::MOP::Class->initialize('DBIx::Class::Storage::DBIHacks')->get_method_list ], |
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322 | reader => [qw/ |
323 | select |
324 | select_single |
325 | columns_info_for |
326 | _dbh_columns_info_for |
327 | _select |
328 | /], |
329 | unimplemented => [qw/ |
330 | _arm_global_destructor |
331 | _verify_pid |
332 | |
0e773352 |
333 | source_bind_attributes |
334 | |
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335 | get_use_dbms_capability |
336 | set_use_dbms_capability |
337 | get_dbms_capability |
338 | set_dbms_capability |
339 | _dbh_details |
340 | _dbh_get_info |
341 | |
342 | sql_limit_dialect |
343 | sql_quote_char |
344 | sql_name_sep |
345 | |
4bea1fe7 |
346 | _prefetch_autovalues |
fabbd5cc |
347 | _perform_autoinc_retrieval |
348 | _autoinc_supplied_for_op |
4bea1fe7 |
349 | |
eec07bca |
350 | _resolve_bindattrs |
351 | |
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352 | _max_column_bytesize |
353 | _is_lob_type |
354 | _is_binary_lob_type |
355 | _is_text_lob_type |
402ac1c9 |
356 | |
357 | sth |
4bea1fe7 |
358 | /,( |
359 | # the capability framework |
360 | # not sure if CMOP->initialize does evil things to DBIC::S::DBI, fix if a problem |
361 | grep |
362 | { $_ =~ /^ _ (?: use | supports | determine_supports ) _ /x } |
363 | ( Class::MOP::Class->initialize('DBIx::Class::Storage::DBI')->get_all_method_names ) |
364 | )], |
365 | }; |
366 | |
367 | if (DBIx::Class::_ENV_::DBICTEST) { |
368 | |
369 | my $seen; |
370 | for my $type (keys %$method_dispatch) { |
371 | for (@{$method_dispatch->{$type}}) { |
372 | push @{$seen->{$_}}, $type; |
373 | } |
374 | } |
cb6ec758 |
375 | |
4bea1fe7 |
376 | if (my @dupes = grep { @{$seen->{$_}} > 1 } keys %$seen) { |
377 | die(join "\n", '', |
378 | 'The following methods show up multiple times in ::Storage::DBI::Replicated handlers:', |
379 | (map { "$_: " . (join ', ', @{$seen->{$_}}) } sort @dupes), |
380 | '', |
381 | ); |
382 | } |
bbdda281 |
383 | |
4bea1fe7 |
384 | if (my @cant = grep { ! DBIx::Class::Storage::DBI->can($_) } keys %$seen) { |
385 | die(join "\n", '', |
386 | '::Storage::DBI::Replicated specifies handling of the following *NON EXISTING* ::Storage::DBI methods:', |
387 | @cant, |
388 | '', |
389 | ); |
390 | } |
391 | } |
bbdda281 |
392 | |
4bea1fe7 |
393 | for my $method (@{$method_dispatch->{unimplemented}}) { |
394 | __PACKAGE__->meta->add_method($method, sub { |
70c28808 |
395 | my $self = shift; |
396 | $self->throw_exception("$method must not be called on ".(blessed $self).' objects'); |
4bea1fe7 |
397 | }); |
398 | } |
31a8aaaf |
399 | |
4bea1fe7 |
400 | =head2 read_handler |
584ea6e4 |
401 | |
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402 | Defines an object that implements the read side of L<BIx::Class::Storage::DBI>. |
584ea6e4 |
403 | |
4bea1fe7 |
404 | =cut |
405 | |
406 | has 'read_handler' => ( |
407 | is=>'rw', |
408 | isa=>Object, |
409 | lazy_build=>1, |
410 | handles=>$method_dispatch->{reader}, |
e471ab87 |
411 | ); |
412 | |
4bea1fe7 |
413 | =head2 write_handler |
414 | |
415 | Defines an object that implements the write side of L<BIx::Class::Storage::DBI>, |
416 | as well as methods that don't write or read that can be called on only one |
417 | storage, methods that return a C<$dbh>, and any methods that don't make sense to |
418 | run on a replicant. |
419 | |
420 | =cut |
421 | |
422 | has 'write_handler' => ( |
423 | is=>'ro', |
424 | isa=>Object, |
425 | lazy_build=>1, |
426 | handles=>$method_dispatch->{writer}, |
7f4433eb |
427 | ); |
428 | |
4bea1fe7 |
429 | |
6d766626 |
430 | |
b2e4d522 |
431 | has _master_connect_info_opts => |
432 | (is => 'rw', isa => HashRef, default => sub { {} }); |
433 | |
434 | =head2 around: connect_info |
435 | |
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436 | Preserves master's C<connect_info> options (for merging with replicants.) |
437 | Also sets any Replicated-related options from connect_info, such as |
dcdf7b2c |
438 | C<pool_type>, C<pool_args>, C<balancer_type> and C<balancer_args>. |
b2e4d522 |
439 | |
440 | =cut |
441 | |
442 | around connect_info => sub { |
443 | my ($next, $self, $info, @extra) = @_; |
444 | |
282a9a4f |
445 | my $merge = Hash::Merge->new('LEFT_PRECEDENT'); |
e666c5fd |
446 | |
b2e4d522 |
447 | my %opts; |
448 | for my $arg (@$info) { |
449 | next unless (reftype($arg)||'') eq 'HASH'; |
e666c5fd |
450 | %opts = %{ $merge->merge($arg, \%opts) }; |
b2e4d522 |
451 | } |
b2e4d522 |
452 | delete $opts{dsn}; |
453 | |
dcdf7b2c |
454 | if (@opts{qw/pool_type pool_args/}) { |
455 | $self->pool_type(delete $opts{pool_type}) |
456 | if $opts{pool_type}; |
457 | |
b88b85e7 |
458 | $self->pool_args( |
e666c5fd |
459 | $merge->merge((delete $opts{pool_args} || {}), $self->pool_args) |
b88b85e7 |
460 | ); |
dcdf7b2c |
461 | |
64ae1667 |
462 | ## Since we possibly changed the pool_args, we need to clear the current |
463 | ## pool object so that next time it is used it will be rebuilt. |
464 | $self->clear_pool; |
dcdf7b2c |
465 | } |
466 | |
467 | if (@opts{qw/balancer_type balancer_args/}) { |
468 | $self->balancer_type(delete $opts{balancer_type}) |
469 | if $opts{balancer_type}; |
470 | |
b88b85e7 |
471 | $self->balancer_args( |
e666c5fd |
472 | $merge->merge((delete $opts{balancer_args} || {}), $self->balancer_args) |
b88b85e7 |
473 | ); |
dcdf7b2c |
474 | |
67c43863 |
475 | $self->balancer($self->_build_balancer) |
6f7344b8 |
476 | if $self->balancer; |
dcdf7b2c |
477 | } |
478 | |
b2e4d522 |
479 | $self->_master_connect_info_opts(\%opts); |
480 | |
1abccf54 |
481 | return preserve_context { |
482 | $self->$next($info, @extra); |
483 | } after => sub { |
484 | # Make sure master is blessed into the correct class and apply role to it. |
485 | my $master = $self->master; |
486 | $master->_determine_driver; |
487 | Moose::Meta::Class->initialize(ref $master); |
cea43436 |
488 | |
1abccf54 |
489 | DBIx::Class::Storage::DBI::Replicated::WithDSN->meta->apply($master); |
0ce2d0d5 |
490 | |
1abccf54 |
491 | # link pool back to master |
492 | $self->pool->master($master); |
493 | }; |
b2e4d522 |
494 | }; |
495 | |
26ab719a |
496 | =head1 METHODS |
2bf79155 |
497 | |
26ab719a |
498 | This class defines the following methods. |
2bf79155 |
499 | |
c354902c |
500 | =head2 BUILDARGS |
2bf79155 |
501 | |
faaba25f |
502 | L<DBIx::Class::Schema> when instantiating its storage passed itself as the |
2ce6e9a6 |
503 | first argument. So we need to massage the arguments a bit so that all the |
504 | bits get put into the correct places. |
2bf79155 |
505 | |
506 | =cut |
507 | |
c354902c |
508 | sub BUILDARGS { |
fd323bf1 |
509 | my ($class, $schema, $storage_type_args, @args) = @_; |
d4daee7b |
510 | |
c354902c |
511 | return { |
6f7344b8 |
512 | schema=>$schema, |
513 | %$storage_type_args, |
514 | @args |
c354902c |
515 | } |
516 | } |
2bf79155 |
517 | |
cb6ec758 |
518 | =head2 _build_master |
2bf79155 |
519 | |
cb6ec758 |
520 | Lazy builder for the L</master> attribute. |
2bf79155 |
521 | |
522 | =cut |
523 | |
cb6ec758 |
524 | sub _build_master { |
2ce6e9a6 |
525 | my $self = shift @_; |
ee356d00 |
526 | my $master = DBIx::Class::Storage::DBI->new($self->schema); |
ee356d00 |
527 | $master |
106d5f3b |
528 | } |
529 | |
26ab719a |
530 | =head2 _build_pool |
2bf79155 |
531 | |
26ab719a |
532 | Lazy builder for the L</pool> attribute. |
2bf79155 |
533 | |
534 | =cut |
535 | |
26ab719a |
536 | sub _build_pool { |
64cdad22 |
537 | my $self = shift @_; |
538 | $self->create_pool(%{$self->pool_args}); |
2bf79155 |
539 | } |
540 | |
26ab719a |
541 | =head2 _build_balancer |
2bf79155 |
542 | |
cb6ec758 |
543 | Lazy builder for the L</balancer> attribute. This takes a Pool object so that |
544 | the balancer knows which pool it's balancing. |
2bf79155 |
545 | |
546 | =cut |
547 | |
26ab719a |
548 | sub _build_balancer { |
64cdad22 |
549 | my $self = shift @_; |
550 | $self->create_balancer( |
6f7344b8 |
551 | pool=>$self->pool, |
64cdad22 |
552 | master=>$self->master, |
553 | %{$self->balancer_args}, |
554 | ); |
2bf79155 |
555 | } |
556 | |
cb6ec758 |
557 | =head2 _build_write_handler |
2bf79155 |
558 | |
cb6ec758 |
559 | Lazy builder for the L</write_handler> attribute. The default is to set this to |
560 | the L</master>. |
50336325 |
561 | |
562 | =cut |
563 | |
cb6ec758 |
564 | sub _build_write_handler { |
64cdad22 |
565 | return shift->master; |
cb6ec758 |
566 | } |
50336325 |
567 | |
cb6ec758 |
568 | =head2 _build_read_handler |
2bf79155 |
569 | |
cb6ec758 |
570 | Lazy builder for the L</read_handler> attribute. The default is to set this to |
571 | the L</balancer>. |
2bf79155 |
572 | |
573 | =cut |
574 | |
cb6ec758 |
575 | sub _build_read_handler { |
64cdad22 |
576 | return shift->balancer; |
cb6ec758 |
577 | } |
50336325 |
578 | |
cb6ec758 |
579 | =head2 around: connect_replicants |
2bf79155 |
580 | |
cb6ec758 |
581 | All calls to connect_replicants needs to have an existing $schema tacked onto |
b2e4d522 |
582 | top of the args, since L<DBIx::Storage::DBI> needs it, and any C<connect_info> |
583 | options merged with the master, with replicant opts having higher priority. |
955a6df6 |
584 | |
cb6ec758 |
585 | =cut |
955a6df6 |
586 | |
b2e4d522 |
587 | around connect_replicants => sub { |
588 | my ($next, $self, @args) = @_; |
589 | |
590 | for my $r (@args) { |
591 | $r = [ $r ] unless reftype $r eq 'ARRAY'; |
592 | |
1a58752c |
593 | $self->throw_exception('coderef replicant connect_info not supported') |
b2e4d522 |
594 | if ref $r->[0] && reftype $r->[0] eq 'CODE'; |
595 | |
596 | # any connect_info options? |
597 | my $i = 0; |
598 | $i++ while $i < @$r && (reftype($r->[$i])||'') ne 'HASH'; |
599 | |
6f7344b8 |
600 | # make one if none |
b2e4d522 |
601 | $r->[$i] = {} unless $r->[$i]; |
602 | |
603 | # merge if two hashes |
b88b85e7 |
604 | my @hashes = @$r[$i .. $#{$r}]; |
605 | |
1a58752c |
606 | $self->throw_exception('invalid connect_info options') |
b88b85e7 |
607 | if (grep { reftype($_) eq 'HASH' } @hashes) != @hashes; |
608 | |
1a58752c |
609 | $self->throw_exception('too many hashrefs in connect_info') |
b88b85e7 |
610 | if @hashes > 2; |
611 | |
282a9a4f |
612 | my $merge = Hash::Merge->new('LEFT_PRECEDENT'); |
e666c5fd |
613 | my %opts = %{ $merge->merge(reverse @hashes) }; |
b88b85e7 |
614 | |
615 | # delete them |
b2e4d522 |
616 | splice @$r, $i+1, ($#{$r} - $i), (); |
617 | |
0bd8e058 |
618 | # make sure master/replicants opts don't clash |
619 | my %master_opts = %{ $self->_master_connect_info_opts }; |
620 | if (exists $opts{dbh_maker}) { |
621 | delete @master_opts{qw/dsn user password/}; |
622 | } |
623 | delete $master_opts{dbh_maker}; |
624 | |
b2e4d522 |
625 | # merge with master |
e666c5fd |
626 | %opts = %{ $merge->merge(\%opts, \%master_opts) }; |
b2e4d522 |
627 | |
628 | # update |
629 | $r->[$i] = \%opts; |
630 | } |
631 | |
632 | $self->$next($self->schema, @args); |
955a6df6 |
633 | }; |
2bf79155 |
634 | |
2bf79155 |
635 | =head2 all_storages |
636 | |
637 | Returns an array of of all the connected storage backends. The first element |
638 | in the returned array is the master, and the remainings are each of the |
639 | replicants. |
640 | |
641 | =cut |
642 | |
643 | sub all_storages { |
64cdad22 |
644 | my $self = shift @_; |
645 | return grep {defined $_ && blessed $_} ( |
646 | $self->master, |
6412a592 |
647 | values %{ $self->replicants }, |
64cdad22 |
648 | ); |
2bf79155 |
649 | } |
650 | |
c4d3fae2 |
651 | =head2 execute_reliably ($coderef, ?@args) |
652 | |
653 | Given a coderef, saves the current state of the L</read_handler>, forces it to |
48580715 |
654 | use reliable storage (e.g. sets it to the master), executes a coderef and then |
c4d3fae2 |
655 | restores the original state. |
656 | |
657 | Example: |
658 | |
64cdad22 |
659 | my $reliably = sub { |
660 | my $name = shift @_; |
661 | $schema->resultset('User')->create({name=>$name}); |
fd323bf1 |
662 | my $user_rs = $schema->resultset('User')->find({name=>$name}); |
64cdad22 |
663 | return $user_rs; |
664 | }; |
c4d3fae2 |
665 | |
64cdad22 |
666 | my $user_rs = $schema->storage->execute_reliably($reliably, 'John'); |
c4d3fae2 |
667 | |
668 | Use this when you must be certain of your database state, such as when you just |
669 | inserted something and need to get a resultset including it, etc. |
670 | |
671 | =cut |
672 | |
673 | sub execute_reliably { |
1abccf54 |
674 | my $self = shift; |
675 | my $coderef = shift; |
d4daee7b |
676 | |
64cdad22 |
677 | unless( ref $coderef eq 'CODE') { |
678 | $self->throw_exception('Second argument must be a coderef'); |
679 | } |
d4daee7b |
680 | |
1abccf54 |
681 | ## replace the current read handler for the remainder of the scope |
682 | local $self->{read_handler} = $self->master; |
d4daee7b |
683 | |
1abccf54 |
684 | my $args = \@_; |
685 | return try { |
686 | $coderef->(@$args); |
ed7ab0f4 |
687 | } catch { |
688 | $self->throw_exception("coderef returned an error: $_"); |
64cdad22 |
689 | }; |
c4d3fae2 |
690 | } |
691 | |
cb6ec758 |
692 | =head2 set_reliable_storage |
693 | |
694 | Sets the current $schema to be 'reliable', that is all queries, both read and |
695 | write are sent to the master |
d4daee7b |
696 | |
cb6ec758 |
697 | =cut |
698 | |
699 | sub set_reliable_storage { |
64cdad22 |
700 | my $self = shift @_; |
701 | my $schema = $self->schema; |
702 | my $write_handler = $self->schema->storage->write_handler; |
d4daee7b |
703 | |
64cdad22 |
704 | $schema->storage->read_handler($write_handler); |
cb6ec758 |
705 | } |
706 | |
707 | =head2 set_balanced_storage |
708 | |
709 | Sets the current $schema to be use the </balancer> for all reads, while all |
48580715 |
710 | writes are sent to the master only |
d4daee7b |
711 | |
cb6ec758 |
712 | =cut |
713 | |
714 | sub set_balanced_storage { |
64cdad22 |
715 | my $self = shift @_; |
716 | my $schema = $self->schema; |
bd5da369 |
717 | my $balanced_handler = $self->schema->storage->balancer; |
d4daee7b |
718 | |
bd5da369 |
719 | $schema->storage->read_handler($balanced_handler); |
cb6ec758 |
720 | } |
2bf79155 |
721 | |
722 | =head2 connected |
723 | |
724 | Check that the master and at least one of the replicants is connected. |
725 | |
726 | =cut |
727 | |
728 | sub connected { |
64cdad22 |
729 | my $self = shift @_; |
730 | return |
731 | $self->master->connected && |
732 | $self->pool->connected_replicants; |
2bf79155 |
733 | } |
734 | |
2bf79155 |
735 | =head2 ensure_connected |
736 | |
737 | Make sure all the storages are connected. |
738 | |
739 | =cut |
740 | |
741 | sub ensure_connected { |
64cdad22 |
742 | my $self = shift @_; |
743 | foreach my $source ($self->all_storages) { |
744 | $source->ensure_connected(@_); |
745 | } |
2bf79155 |
746 | } |
747 | |
2bf79155 |
748 | =head2 limit_dialect |
749 | |
750 | Set the limit_dialect for all existing storages |
751 | |
752 | =cut |
753 | |
754 | sub limit_dialect { |
64cdad22 |
755 | my $self = shift @_; |
756 | foreach my $source ($self->all_storages) { |
757 | $source->limit_dialect(@_); |
758 | } |
f3e9f010 |
759 | return $self->master->limit_dialect; |
2bf79155 |
760 | } |
761 | |
2bf79155 |
762 | =head2 quote_char |
763 | |
764 | Set the quote_char for all existing storages |
765 | |
766 | =cut |
767 | |
768 | sub quote_char { |
64cdad22 |
769 | my $self = shift @_; |
770 | foreach my $source ($self->all_storages) { |
771 | $source->quote_char(@_); |
772 | } |
3fbe08e3 |
773 | return $self->master->quote_char; |
2bf79155 |
774 | } |
775 | |
2bf79155 |
776 | =head2 name_sep |
777 | |
778 | Set the name_sep for all existing storages |
779 | |
780 | =cut |
781 | |
782 | sub name_sep { |
64cdad22 |
783 | my $self = shift @_; |
784 | foreach my $source ($self->all_storages) { |
785 | $source->name_sep(@_); |
786 | } |
3fbe08e3 |
787 | return $self->master->name_sep; |
2bf79155 |
788 | } |
789 | |
2bf79155 |
790 | =head2 set_schema |
791 | |
792 | Set the schema object for all existing storages |
793 | |
794 | =cut |
795 | |
796 | sub set_schema { |
64cdad22 |
797 | my $self = shift @_; |
798 | foreach my $source ($self->all_storages) { |
799 | $source->set_schema(@_); |
800 | } |
2bf79155 |
801 | } |
802 | |
2bf79155 |
803 | =head2 debug |
804 | |
805 | set a debug flag across all storages |
806 | |
807 | =cut |
808 | |
809 | sub debug { |
64cdad22 |
810 | my $self = shift @_; |
3fbe08e3 |
811 | if(@_) { |
812 | foreach my $source ($self->all_storages) { |
813 | $source->debug(@_); |
6f7344b8 |
814 | } |
64cdad22 |
815 | } |
3fbe08e3 |
816 | return $self->master->debug; |
2bf79155 |
817 | } |
818 | |
2bf79155 |
819 | =head2 debugobj |
820 | |
cea43436 |
821 | set a debug object |
2bf79155 |
822 | |
823 | =cut |
824 | |
825 | sub debugobj { |
64cdad22 |
826 | my $self = shift @_; |
cea43436 |
827 | return $self->master->debugobj(@_); |
2bf79155 |
828 | } |
829 | |
2bf79155 |
830 | =head2 debugfh |
831 | |
cea43436 |
832 | set a debugfh object |
2bf79155 |
833 | |
834 | =cut |
835 | |
836 | sub debugfh { |
64cdad22 |
837 | my $self = shift @_; |
cea43436 |
838 | return $self->master->debugfh(@_); |
2bf79155 |
839 | } |
840 | |
2bf79155 |
841 | =head2 debugcb |
842 | |
cea43436 |
843 | set a debug callback |
2bf79155 |
844 | |
845 | =cut |
846 | |
847 | sub debugcb { |
64cdad22 |
848 | my $self = shift @_; |
cea43436 |
849 | return $self->master->debugcb(@_); |
2bf79155 |
850 | } |
851 | |
2bf79155 |
852 | =head2 disconnect |
853 | |
854 | disconnect everything |
855 | |
856 | =cut |
857 | |
858 | sub disconnect { |
64cdad22 |
859 | my $self = shift @_; |
860 | foreach my $source ($self->all_storages) { |
861 | $source->disconnect(@_); |
862 | } |
2bf79155 |
863 | } |
864 | |
b2e4d522 |
865 | =head2 cursor_class |
866 | |
867 | set cursor class on all storages, or return master's |
868 | |
869 | =cut |
870 | |
871 | sub cursor_class { |
872 | my ($self, $cursor_class) = @_; |
873 | |
874 | if ($cursor_class) { |
875 | $_->cursor_class($cursor_class) for $self->all_storages; |
876 | } |
877 | $self->master->cursor_class; |
878 | } |
d4daee7b |
879 | |
3244fdcc |
880 | =head2 cursor |
881 | |
882 | set cursor class on all storages, or return master's, alias for L</cursor_class> |
883 | above. |
884 | |
885 | =cut |
886 | |
887 | sub cursor { |
888 | my ($self, $cursor_class) = @_; |
889 | |
890 | if ($cursor_class) { |
891 | $_->cursor($cursor_class) for $self->all_storages; |
892 | } |
893 | $self->master->cursor; |
894 | } |
895 | |
896 | =head2 unsafe |
897 | |
898 | sets the L<DBIx::Class::Storage::DBI/unsafe> option on all storages or returns |
899 | master's current setting |
900 | |
901 | =cut |
902 | |
903 | sub unsafe { |
904 | my $self = shift; |
905 | |
906 | if (@_) { |
907 | $_->unsafe(@_) for $self->all_storages; |
908 | } |
909 | |
910 | return $self->master->unsafe; |
911 | } |
912 | |
913 | =head2 disable_sth_caching |
914 | |
915 | sets the L<DBIx::Class::Storage::DBI/disable_sth_caching> option on all storages |
916 | or returns master's current setting |
917 | |
918 | =cut |
919 | |
920 | sub disable_sth_caching { |
921 | my $self = shift; |
922 | |
923 | if (@_) { |
924 | $_->disable_sth_caching(@_) for $self->all_storages; |
925 | } |
926 | |
927 | return $self->master->disable_sth_caching; |
928 | } |
929 | |
930 | =head2 lag_behind_master |
931 | |
932 | returns the highest Replicant L<DBIx::Class::Storage::DBI/lag_behind_master> |
933 | setting |
934 | |
935 | =cut |
936 | |
937 | sub lag_behind_master { |
938 | my $self = shift; |
939 | |
940 | return max map $_->lag_behind_master, $self->replicants; |
fd323bf1 |
941 | } |
3244fdcc |
942 | |
943 | =head2 is_replicating |
944 | |
945 | returns true if all replicants return true for |
946 | L<DBIx::Class::Storage::DBI/is_replicating> |
947 | |
948 | =cut |
949 | |
950 | sub is_replicating { |
951 | my $self = shift; |
952 | |
953 | return (grep $_->is_replicating, $self->replicants) == ($self->replicants); |
954 | } |
955 | |
956 | =head2 connect_call_datetime_setup |
957 | |
958 | calls L<DBIx::Class::Storage::DBI/connect_call_datetime_setup> for all storages |
959 | |
960 | =cut |
961 | |
962 | sub connect_call_datetime_setup { |
963 | my $self = shift; |
964 | $_->connect_call_datetime_setup for $self->all_storages; |
965 | } |
966 | |
967 | sub _populate_dbh { |
968 | my $self = shift; |
969 | $_->_populate_dbh for $self->all_storages; |
970 | } |
971 | |
972 | sub _connect { |
973 | my $self = shift; |
974 | $_->_connect for $self->all_storages; |
975 | } |
976 | |
977 | sub _rebless { |
978 | my $self = shift; |
979 | $_->_rebless for $self->all_storages; |
980 | } |
981 | |
982 | sub _determine_driver { |
983 | my $self = shift; |
984 | $_->_determine_driver for $self->all_storages; |
985 | } |
986 | |
987 | sub _driver_determined { |
988 | my $self = shift; |
fd323bf1 |
989 | |
3244fdcc |
990 | if (@_) { |
991 | $_->_driver_determined(@_) for $self->all_storages; |
992 | } |
993 | |
994 | return $self->master->_driver_determined; |
995 | } |
996 | |
997 | sub _init { |
998 | my $self = shift; |
fd323bf1 |
999 | |
3244fdcc |
1000 | $_->_init for $self->all_storages; |
1001 | } |
1002 | |
1003 | sub _run_connection_actions { |
1004 | my $self = shift; |
fd323bf1 |
1005 | |
3244fdcc |
1006 | $_->_run_connection_actions for $self->all_storages; |
1007 | } |
1008 | |
1009 | sub _do_connection_actions { |
1010 | my $self = shift; |
fd323bf1 |
1011 | |
3244fdcc |
1012 | if (@_) { |
1013 | $_->_do_connection_actions(@_) for $self->all_storages; |
1014 | } |
1015 | } |
1016 | |
1017 | sub connect_call_do_sql { |
1018 | my $self = shift; |
1019 | $_->connect_call_do_sql(@_) for $self->all_storages; |
1020 | } |
1021 | |
1022 | sub disconnect_call_do_sql { |
1023 | my $self = shift; |
1024 | $_->disconnect_call_do_sql(@_) for $self->all_storages; |
1025 | } |
1026 | |
1027 | sub _seems_connected { |
1028 | my $self = shift; |
1029 | |
1030 | return min map $_->_seems_connected, $self->all_storages; |
1031 | } |
1032 | |
1033 | sub _ping { |
1034 | my $self = shift; |
1035 | |
1036 | return min map $_->_ping, $self->all_storages; |
1037 | } |
1038 | |
bbdda281 |
1039 | # not using the normalized_version, because we want to preserve |
1040 | # version numbers much longer than the conventional xxx.yyyzzz |
7da56142 |
1041 | my $numify_ver = sub { |
1042 | my $ver = shift; |
1043 | my @numparts = split /\D+/, $ver; |
bbdda281 |
1044 | my $format = '%d.' . (join '', ('%06d') x (@numparts - 1)); |
7da56142 |
1045 | |
1046 | return sprintf $format, @numparts; |
1047 | }; |
fecb38cb |
1048 | sub _server_info { |
1049 | my $self = shift; |
1050 | |
bbdda281 |
1051 | if (not $self->_dbh_details->{info}) { |
1052 | $self->_dbh_details->{info} = ( |
fd323bf1 |
1053 | reduce { $a->[0] < $b->[0] ? $a : $b } |
7da56142 |
1054 | map [ $numify_ver->($_->{dbms_version}), $_ ], |
1055 | map $_->_server_info, $self->all_storages |
1056 | )->[1]; |
fecb38cb |
1057 | } |
1058 | |
bbdda281 |
1059 | return $self->next::method; |
fecb38cb |
1060 | } |
1061 | |
1062 | sub _get_server_version { |
1063 | my $self = shift; |
1064 | |
1065 | return $self->_server_info->{dbms_version}; |
1066 | } |
1067 | |
7e38d850 |
1068 | =head1 GOTCHAS |
1069 | |
1070 | Due to the fact that replicants can lag behind a master, you must take care to |
1071 | make sure you use one of the methods to force read queries to a master should |
1072 | you need realtime data integrity. For example, if you insert a row, and then |
1073 | immediately re-read it from the database (say, by doing $row->discard_changes) |
1074 | or you insert a row and then immediately build a query that expects that row |
1075 | to be an item, you should force the master to handle reads. Otherwise, due to |
1076 | the lag, there is no certainty your data will be in the expected state. |
1077 | |
1078 | For data integrity, all transactions automatically use the master storage for |
1079 | all read and write queries. Using a transaction is the preferred and recommended |
1080 | method to force the master to handle all read queries. |
1081 | |
1082 | Otherwise, you can force a single query to use the master with the 'force_pool' |
1083 | attribute: |
1084 | |
1085 | my $row = $resultset->search(undef, {force_pool=>'master'})->find($pk); |
1086 | |
1087 | This attribute will safely be ignore by non replicated storages, so you can use |
1088 | the same code for both types of systems. |
1089 | |
1090 | Lastly, you can use the L</execute_reliably> method, which works very much like |
1091 | a transaction. |
1092 | |
1093 | For debugging, you can turn replication on/off with the methods L</set_reliable_storage> |
1094 | and L</set_balanced_storage>, however this operates at a global level and is not |
1095 | suitable if you have a shared Schema object being used by multiple processes, |
1096 | such as on a web application server. You can get around this limitation by |
1097 | using the Schema clone method. |
1098 | |
1099 | my $new_schema = $schema->clone; |
1100 | $new_schema->set_reliable_storage; |
d4daee7b |
1101 | |
7e38d850 |
1102 | ## $new_schema will use only the Master storage for all reads/writes while |
1103 | ## the $schema object will use replicated storage. |
1104 | |
f5d3a5de |
1105 | =head1 AUTHOR |
1106 | |
64cdad22 |
1107 | John Napiorkowski <john.napiorkowski@takkle.com> |
f5d3a5de |
1108 | |
c4d3fae2 |
1109 | Based on code originated by: |
f5d3a5de |
1110 | |
64cdad22 |
1111 | Norbert Csongrádi <bert@cpan.org> |
1112 | Peter Siklósi <einon@einon.hu> |
2156bbdd |
1113 | |
f5d3a5de |
1114 | =head1 LICENSE |
1115 | |
1116 | You may distribute this code under the same terms as Perl itself. |
1117 | |
1118 | =cut |
1119 | |
c354902c |
1120 | __PACKAGE__->meta->make_immutable; |
1121 | |
f5d3a5de |
1122 | 1; |