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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/; |
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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 | |
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10 | use Moo; |
11 | use Role::Tiny (); |
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12 | use DBIx::Class::Storage::DBI; |
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13 | use Scalar::Util qw(reftype blessed); |
14 | use List::Util qw(min max reduce); |
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15 | use Try::Tiny; |
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16 | use Sub::Name 'subname'; |
17 | use Class::Inspector; |
18 | use DBIx::Class::Storage::DBI::Replicated::Types |
19 | qw(DBICSchema DBICStorageDBI ClassName HashRef Object |
20 | DoesDBICStorageReplicatedBalancer DBICStorageDBIReplicatedPool Defined); |
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21 | |
22 | =head1 NAME |
23 | |
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24 | DBIx::Class::Storage::DBI::Replicated - BETA Replicated database support |
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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 | |
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32 | You should set the 'storage_type attribute to a replicated type. You should |
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33 | also define your arguments, such as which balancer you want and any arguments |
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34 | that the Pool object should get. |
35 | |
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36 | my $schema = Schema::Class->clone; |
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37 | $schema->storage_type( ['::DBI::Replicated', {balancer=>'::Random'}] ); |
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38 | $schema->connection(...); |
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39 | |
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40 | Next, you need to add in the Replicants. Basically this is an array of |
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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. |
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43 | |
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44 | $schema->storage->connect_replicants( |
45 | [$dsn1, $user, $pass, \%opts], |
46 | [$dsn2, $user, $pass, \%opts], |
47 | [$dsn3, $user, $pass, \%opts], |
48 | ); |
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49 | |
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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 | |
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53 | $schema->resultset('Source')->search({name=>'etc'}); |
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54 | |
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55 | You can force a given query to use a particular storage using the search |
56 | attribute 'force_pool'. For example: |
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57 | |
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58 | my $RS = $schema->resultset('Source')->search(undef, {force_pool=>'master'}); |
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59 | |
60 | Now $RS will force everything (both reads and writes) to use whatever was setup |
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61 | as the master storage. 'master' is hardcoded to always point to the Master, |
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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. |
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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 |
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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 |
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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 | |
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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 |
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105 | L<DBIx::Class>. See L<DBIx::Class::Optional::Dependencies> for more details. |
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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' => ( |
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118 | is=>'rw', |
119 | isa=>DBICSchema, |
120 | weak_ref=>1, |
121 | required=>1, |
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122 | ); |
123 | |
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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 |
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127 | to: L<DBIx::Class::Storage::DBI::Replicated::Pool>. |
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128 | |
129 | =cut |
130 | |
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131 | has 'pool_type' => ( |
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132 | is=>'rw', |
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133 | isa=>ClassName, |
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134 | default=> sub { 'DBIx::Class::Storage::DBI::Replicated::Pool'}, |
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135 | handles=>{ |
136 | 'create_pool' => 'new', |
137 | }, |
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138 | ); |
139 | |
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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. |
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144 | |
145 | =cut |
146 | |
147 | has 'pool_args' => ( |
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148 | is=>'rw', |
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149 | isa =>HashRef, |
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150 | lazy=>1, |
64cdad22 |
151 | default=>sub { {} }, |
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152 | ); |
153 | |
154 | |
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155 | =head2 balancer_type |
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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 | |
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162 | has 'balancer_type' => ( |
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163 | is=>'rw', |
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164 | isa=>Defined, |
165 | default=>sub { 'DBIx::Class::Storage::DBI::Replicated::Balancer::First' }, |
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166 | ); |
167 | |
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168 | sub create_balancer { |
169 | my ($self, @args) = @_; |
170 | my $type = $self->balancer_type; |
171 | $type = 'DBIx::Class::Storage::DBI::Replicated::Balancer'.$type |
172 | if ($type=~m/^::/); |
173 | $self->schema->ensure_class_loaded($type); |
174 | return $type->new(@args); |
175 | } |
176 | |
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177 | =head2 balancer_args |
178 | |
179 | Contains a hashref of initialized information to pass to the Balancer object. |
212cc5c2 |
180 | See L<DBIx::Class::Storage::DBI::Replicated::Balancer> for available arguments. |
17b05c13 |
181 | |
182 | =cut |
183 | |
184 | has 'balancer_args' => ( |
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185 | is=>'rw', |
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186 | isa =>HashRef, |
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187 | lazy=>1, |
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188 | default=>sub { +{} }, |
17b05c13 |
189 | ); |
190 | |
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191 | =head2 pool |
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192 | |
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193 | Is a L<DBIx::Class::Storage::DBI::Replicated::Pool> or derived class. This is a |
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194 | container class for one or more replicated databases. |
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195 | |
196 | =cut |
197 | |
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198 | has 'pool' => ( |
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199 | is=>'ro', |
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200 | isa =>DBICStorageDBIReplicatedPool, |
201 | lazy=>1, |
202 | builder=>'_build_pool', |
203 | clearer=>'clear_pool', |
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204 | handles=>[qw/ |
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205 | connect_replicants |
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206 | replicants |
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207 | /], |
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208 | ); |
209 | |
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210 | =head2 balancer |
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211 | |
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212 | Is a L<DBIx::Class::Storage::DBI::Replicated::Balancer> or derived class. This |
213 | is a class that takes a pool (L<DBIx::Class::Storage::DBI::Replicated::Pool>) |
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214 | |
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215 | =cut |
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216 | |
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217 | has 'balancer' => ( |
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218 | is=>'rw', |
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219 | isa => DoesDBICStorageReplicatedBalancer, |
220 | lazy=>1, |
221 | builder=>'_build_balancer', |
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222 | handles=>[qw/auto_validate_every/], |
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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, |
238 | lazy=>1, |
239 | builder=>'_build_master', |
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240 | ); |
241 | |
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242 | =head1 ATTRIBUTES IMPLEMENTING THE DBIx::Storage::DBI INTERFACE |
243 | |
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244 | The following methods are delegated all the methods required for the |
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245 | L<DBIx::Class::Storage::DBI> interface. |
246 | |
247 | =head2 read_handler |
248 | |
249 | Defines an object that implements the read side of L<BIx::Class::Storage::DBI>. |
250 | |
251 | =cut |
252 | |
253 | has 'read_handler' => ( |
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254 | is=>'rw', |
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255 | isa=>Object, |
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256 | lazy=>1, |
257 | builder=>'_build_read_handler', |
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258 | handles=>[qw/ |
259 | select |
260 | select_single |
261 | columns_info_for |
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262 | _dbh_columns_info_for |
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263 | _select |
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264 | /], |
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265 | ); |
266 | |
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267 | =head2 write_handler |
268 | |
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269 | Defines an object that implements the write side of L<BIx::Class::Storage::DBI>, |
270 | as well as methods that don't write or read that can be called on only one |
271 | storage, methods that return a C<$dbh>, and any methods that don't make sense to |
272 | run on a replicant. |
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273 | |
274 | =cut |
275 | |
276 | has 'write_handler' => ( |
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277 | is=>'ro', |
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278 | isa=>Object, |
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279 | lazy=>1, |
280 | builder=>'_build_write_handler', |
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281 | handles=>[qw/ |
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282 | on_connect_do |
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283 | on_disconnect_do |
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284 | on_connect_call |
285 | on_disconnect_call |
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286 | connect_info |
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287 | _connect_info |
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288 | throw_exception |
289 | sql_maker |
290 | sqlt_type |
291 | create_ddl_dir |
292 | deployment_statements |
293 | datetime_parser |
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294 | datetime_parser_type |
295 | build_datetime_parser |
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296 | last_insert_id |
297 | insert |
298 | insert_bulk |
299 | update |
300 | delete |
301 | dbh |
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302 | txn_begin |
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303 | txn_do |
304 | txn_commit |
305 | txn_rollback |
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306 | txn_scope_guard |
64cdad22 |
307 | sth |
308 | deploy |
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309 | with_deferred_fk_checks |
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310 | dbh_do |
64cdad22 |
311 | reload_row |
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312 | _prep_for_execute |
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313 | |
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314 | backup |
315 | is_datatype_numeric |
316 | _count_select |
6f7344b8 |
317 | _subq_update_delete |
318 | svp_rollback |
319 | svp_begin |
320 | svp_release |
e398f77e |
321 | relname_to_table_alias |
3244fdcc |
322 | _dbh_last_insert_id |
323 | _fix_bind_params |
324 | _default_dbi_connect_attributes |
325 | _dbi_connect_info |
b9ca4ff1 |
326 | _dbic_connect_attributes |
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327 | auto_savepoint |
328 | _sqlt_version_ok |
329 | _query_end |
330 | bind_attribute_by_data_type |
331 | transaction_depth |
332 | _dbh |
333 | _select_args |
334 | _dbh_execute_array |
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335 | _sql_maker |
336 | _query_start |
337 | _sqlt_version_error |
338 | _per_row_update_delete |
339 | _dbh_begin_work |
340 | _dbh_execute_inserts_with_no_binds |
341 | _select_args_to_query |
342 | _svp_generate_name |
343 | _multipk_update_delete |
344 | source_bind_attributes |
345 | _normalize_connect_info |
346 | _parse_connect_do |
347 | _dbh_commit |
348 | _execute_array |
3244fdcc |
349 | savepoints |
350 | _sqlt_minimum_version |
351 | _sql_maker_opts |
352 | _conn_pid |
3244fdcc |
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 |
3244fdcc |
363 | _resolve_aliastypes_from_select_args |
364 | _execute |
365 | _do_query |
366 | _dbh_sth |
367 | _dbh_execute |
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368 | /], |
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369 | ); |
370 | |
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371 | my @unimplemented = qw( |
372 | _arm_global_destructor |
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373 | _preserve_foreign_dbh |
572338e0 |
374 | _verify_pid |
0bbe6676 |
375 | _verify_tid |
bbdda281 |
376 | |
377 | get_use_dbms_capability |
378 | set_use_dbms_capability |
379 | get_dbms_capability |
380 | set_dbms_capability |
bbdda281 |
381 | _dbh_details |
382 | |
7f4433eb |
383 | sql_limit_dialect |
31a8aaaf |
384 | |
385 | _inner_join_to_node |
0a3441ee |
386 | _group_over_selection |
bac358c9 |
387 | _extract_order_criteria |
153a0398 |
388 | _is_lob_type |
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389 | _max_column_bytesize |
390 | _prefetch_autovalues |
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391 | ); |
392 | |
7f4433eb |
393 | # the capability framework |
7f4433eb |
394 | push @unimplemented, ( grep |
395 | { $_ =~ /^ _ (?: use | supports | determine_supports ) _ /x } |
0bbe6676 |
396 | @{Class::Inspector->methods('DBIx::Class::Storage::DBI')||[]} |
7f4433eb |
397 | ); |
398 | |
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399 | for my $method (@unimplemented) { |
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400 | { |
401 | no strict qw/refs/; |
402 | *{__PACKAGE__ ."::$method"} = subname $method => sub { |
403 | croak "$method must not be called on ".(blessed shift).' objects'; |
404 | }; |
405 | } |
e471ab87 |
406 | } |
6d766626 |
407 | |
0bbe6676 |
408 | has _master_connect_info_opts => ( |
409 | is => 'rw', |
410 | isa =>HashRef , |
411 | default => sub { +{} }, |
412 | ); |
b2e4d522 |
413 | |
414 | =head2 around: connect_info |
415 | |
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416 | Preserves master's C<connect_info> options (for merging with replicants.) |
417 | Also sets any Replicated-related options from connect_info, such as |
dcdf7b2c |
418 | C<pool_type>, C<pool_args>, C<balancer_type> and C<balancer_args>. |
b2e4d522 |
419 | |
420 | =cut |
421 | |
422 | around connect_info => sub { |
423 | my ($next, $self, $info, @extra) = @_; |
424 | |
282a9a4f |
425 | my $merge = Hash::Merge->new('LEFT_PRECEDENT'); |
e666c5fd |
426 | |
b2e4d522 |
427 | my %opts; |
428 | for my $arg (@$info) { |
429 | next unless (reftype($arg)||'') eq 'HASH'; |
e666c5fd |
430 | %opts = %{ $merge->merge($arg, \%opts) }; |
b2e4d522 |
431 | } |
b2e4d522 |
432 | delete $opts{dsn}; |
433 | |
dcdf7b2c |
434 | if (@opts{qw/pool_type pool_args/}) { |
435 | $self->pool_type(delete $opts{pool_type}) |
436 | if $opts{pool_type}; |
437 | |
b88b85e7 |
438 | $self->pool_args( |
e666c5fd |
439 | $merge->merge((delete $opts{pool_args} || {}), $self->pool_args) |
b88b85e7 |
440 | ); |
dcdf7b2c |
441 | |
64ae1667 |
442 | ## Since we possibly changed the pool_args, we need to clear the current |
443 | ## pool object so that next time it is used it will be rebuilt. |
444 | $self->clear_pool; |
dcdf7b2c |
445 | } |
446 | |
447 | if (@opts{qw/balancer_type balancer_args/}) { |
448 | $self->balancer_type(delete $opts{balancer_type}) |
449 | if $opts{balancer_type}; |
450 | |
b88b85e7 |
451 | $self->balancer_args( |
e666c5fd |
452 | $merge->merge((delete $opts{balancer_args} || {}), $self->balancer_args) |
b88b85e7 |
453 | ); |
dcdf7b2c |
454 | |
67c43863 |
455 | $self->balancer($self->_build_balancer) |
6f7344b8 |
456 | if $self->balancer; |
dcdf7b2c |
457 | } |
458 | |
b2e4d522 |
459 | $self->_master_connect_info_opts(\%opts); |
460 | |
cca282b6 |
461 | my @res; |
462 | if (wantarray) { |
0ce2d0d5 |
463 | @res = $self->$next($info, @extra); |
464 | } else { |
cca282b6 |
465 | $res[0] = $self->$next($info, @extra); |
0ce2d0d5 |
466 | } |
467 | |
fd4eb9c2 |
468 | # Make sure master is blessed into the correct class and apply role to it. |
469 | my $master = $self->master; |
470 | $master->_determine_driver; |
cea43436 |
471 | |
0bbe6676 |
472 | ## Moose::Meta::Class->initialize(ref $master); |
473 | Role::Tiny->apply_roles_to_object($master, 'DBIx::Class::Storage::DBI::Replicated::WithDSN'); |
474 | ## DBIx::Class::Storage::DBI::Replicated::WithDSN->meta->apply($master); |
cea43436 |
475 | |
476 | # link pool back to master |
477 | $self->pool->master($master); |
0ce2d0d5 |
478 | |
cca282b6 |
479 | wantarray ? @res : $res[0]; |
b2e4d522 |
480 | }; |
481 | |
26ab719a |
482 | =head1 METHODS |
2bf79155 |
483 | |
26ab719a |
484 | This class defines the following methods. |
2bf79155 |
485 | |
0bbe6676 |
486 | =head2 new |
2bf79155 |
487 | |
faaba25f |
488 | L<DBIx::Class::Schema> when instantiating its storage passed itself as the |
2ce6e9a6 |
489 | first argument. So we need to massage the arguments a bit so that all the |
490 | bits get put into the correct places. |
2bf79155 |
491 | |
492 | =cut |
493 | |
0bbe6676 |
494 | around 'new', sub { |
495 | my ($orig, $class, $schema, $storage_type_args, @args) = @_; |
496 | return $orig->( |
497 | $class, |
498 | schema => $schema, |
6f7344b8 |
499 | %$storage_type_args, |
0bbe6676 |
500 | @args, |
501 | ); |
502 | }; |
2bf79155 |
503 | |
cb6ec758 |
504 | =head2 _build_master |
2bf79155 |
505 | |
cb6ec758 |
506 | Lazy builder for the L</master> attribute. |
2bf79155 |
507 | |
508 | =cut |
509 | |
cb6ec758 |
510 | sub _build_master { |
2ce6e9a6 |
511 | my $self = shift @_; |
ee356d00 |
512 | my $master = DBIx::Class::Storage::DBI->new($self->schema); |
0bbe6676 |
513 | return $master; |
106d5f3b |
514 | } |
515 | |
26ab719a |
516 | =head2 _build_pool |
2bf79155 |
517 | |
26ab719a |
518 | Lazy builder for the L</pool> attribute. |
2bf79155 |
519 | |
520 | =cut |
521 | |
26ab719a |
522 | sub _build_pool { |
64cdad22 |
523 | my $self = shift @_; |
524 | $self->create_pool(%{$self->pool_args}); |
2bf79155 |
525 | } |
526 | |
26ab719a |
527 | =head2 _build_balancer |
2bf79155 |
528 | |
cb6ec758 |
529 | Lazy builder for the L</balancer> attribute. This takes a Pool object so that |
530 | the balancer knows which pool it's balancing. |
2bf79155 |
531 | |
532 | =cut |
533 | |
26ab719a |
534 | sub _build_balancer { |
64cdad22 |
535 | my $self = shift @_; |
536 | $self->create_balancer( |
6f7344b8 |
537 | pool=>$self->pool, |
64cdad22 |
538 | master=>$self->master, |
539 | %{$self->balancer_args}, |
540 | ); |
2bf79155 |
541 | } |
542 | |
cb6ec758 |
543 | =head2 _build_write_handler |
2bf79155 |
544 | |
cb6ec758 |
545 | Lazy builder for the L</write_handler> attribute. The default is to set this to |
546 | the L</master>. |
50336325 |
547 | |
548 | =cut |
549 | |
cb6ec758 |
550 | sub _build_write_handler { |
64cdad22 |
551 | return shift->master; |
cb6ec758 |
552 | } |
50336325 |
553 | |
cb6ec758 |
554 | =head2 _build_read_handler |
2bf79155 |
555 | |
cb6ec758 |
556 | Lazy builder for the L</read_handler> attribute. The default is to set this to |
557 | the L</balancer>. |
2bf79155 |
558 | |
559 | =cut |
560 | |
cb6ec758 |
561 | sub _build_read_handler { |
64cdad22 |
562 | return shift->balancer; |
cb6ec758 |
563 | } |
50336325 |
564 | |
cb6ec758 |
565 | =head2 around: connect_replicants |
2bf79155 |
566 | |
cb6ec758 |
567 | All calls to connect_replicants needs to have an existing $schema tacked onto |
b2e4d522 |
568 | top of the args, since L<DBIx::Storage::DBI> needs it, and any C<connect_info> |
569 | options merged with the master, with replicant opts having higher priority. |
955a6df6 |
570 | |
cb6ec758 |
571 | =cut |
955a6df6 |
572 | |
b2e4d522 |
573 | around connect_replicants => sub { |
574 | my ($next, $self, @args) = @_; |
575 | |
576 | for my $r (@args) { |
577 | $r = [ $r ] unless reftype $r eq 'ARRAY'; |
578 | |
1a58752c |
579 | $self->throw_exception('coderef replicant connect_info not supported') |
b2e4d522 |
580 | if ref $r->[0] && reftype $r->[0] eq 'CODE'; |
581 | |
582 | # any connect_info options? |
583 | my $i = 0; |
584 | $i++ while $i < @$r && (reftype($r->[$i])||'') ne 'HASH'; |
585 | |
6f7344b8 |
586 | # make one if none |
b2e4d522 |
587 | $r->[$i] = {} unless $r->[$i]; |
588 | |
589 | # merge if two hashes |
b88b85e7 |
590 | my @hashes = @$r[$i .. $#{$r}]; |
591 | |
1a58752c |
592 | $self->throw_exception('invalid connect_info options') |
b88b85e7 |
593 | if (grep { reftype($_) eq 'HASH' } @hashes) != @hashes; |
594 | |
1a58752c |
595 | $self->throw_exception('too many hashrefs in connect_info') |
b88b85e7 |
596 | if @hashes > 2; |
597 | |
282a9a4f |
598 | my $merge = Hash::Merge->new('LEFT_PRECEDENT'); |
e666c5fd |
599 | my %opts = %{ $merge->merge(reverse @hashes) }; |
b88b85e7 |
600 | |
601 | # delete them |
b2e4d522 |
602 | splice @$r, $i+1, ($#{$r} - $i), (); |
603 | |
0bd8e058 |
604 | # make sure master/replicants opts don't clash |
605 | my %master_opts = %{ $self->_master_connect_info_opts }; |
606 | if (exists $opts{dbh_maker}) { |
607 | delete @master_opts{qw/dsn user password/}; |
608 | } |
609 | delete $master_opts{dbh_maker}; |
610 | |
b2e4d522 |
611 | # merge with master |
e666c5fd |
612 | %opts = %{ $merge->merge(\%opts, \%master_opts) }; |
b2e4d522 |
613 | |
614 | # update |
615 | $r->[$i] = \%opts; |
616 | } |
617 | |
618 | $self->$next($self->schema, @args); |
955a6df6 |
619 | }; |
2bf79155 |
620 | |
2bf79155 |
621 | =head2 all_storages |
622 | |
623 | Returns an array of of all the connected storage backends. The first element |
624 | in the returned array is the master, and the remainings are each of the |
625 | replicants. |
626 | |
627 | =cut |
628 | |
629 | sub all_storages { |
64cdad22 |
630 | my $self = shift @_; |
631 | return grep {defined $_ && blessed $_} ( |
632 | $self->master, |
6412a592 |
633 | values %{ $self->replicants }, |
64cdad22 |
634 | ); |
2bf79155 |
635 | } |
636 | |
c4d3fae2 |
637 | =head2 execute_reliably ($coderef, ?@args) |
638 | |
639 | Given a coderef, saves the current state of the L</read_handler>, forces it to |
48580715 |
640 | use reliable storage (e.g. sets it to the master), executes a coderef and then |
c4d3fae2 |
641 | restores the original state. |
642 | |
643 | Example: |
644 | |
64cdad22 |
645 | my $reliably = sub { |
646 | my $name = shift @_; |
647 | $schema->resultset('User')->create({name=>$name}); |
fd323bf1 |
648 | my $user_rs = $schema->resultset('User')->find({name=>$name}); |
64cdad22 |
649 | return $user_rs; |
650 | }; |
c4d3fae2 |
651 | |
64cdad22 |
652 | my $user_rs = $schema->storage->execute_reliably($reliably, 'John'); |
c4d3fae2 |
653 | |
654 | Use this when you must be certain of your database state, such as when you just |
655 | inserted something and need to get a resultset including it, etc. |
656 | |
657 | =cut |
658 | |
659 | sub execute_reliably { |
64cdad22 |
660 | my ($self, $coderef, @args) = @_; |
d4daee7b |
661 | |
64cdad22 |
662 | unless( ref $coderef eq 'CODE') { |
663 | $self->throw_exception('Second argument must be a coderef'); |
664 | } |
d4daee7b |
665 | |
64cdad22 |
666 | ##Get copy of master storage |
667 | my $master = $self->master; |
d4daee7b |
668 | |
64cdad22 |
669 | ##Get whatever the current read hander is |
670 | my $current = $self->read_handler; |
d4daee7b |
671 | |
64cdad22 |
672 | ##Set the read handler to master |
673 | $self->read_handler($master); |
d4daee7b |
674 | |
64cdad22 |
675 | ## do whatever the caller needs |
676 | my @result; |
677 | my $want_array = wantarray; |
d4daee7b |
678 | |
ed7ab0f4 |
679 | try { |
64cdad22 |
680 | if($want_array) { |
681 | @result = $coderef->(@args); |
682 | } elsif(defined $want_array) { |
683 | ($result[0]) = ($coderef->(@args)); |
ed213e85 |
684 | } else { |
64cdad22 |
685 | $coderef->(@args); |
6f7344b8 |
686 | } |
ed7ab0f4 |
687 | } catch { |
688 | $self->throw_exception("coderef returned an error: $_"); |
689 | } finally { |
690 | ##Reset to the original state |
691 | $self->read_handler($current); |
64cdad22 |
692 | }; |
d4daee7b |
693 | |
cca282b6 |
694 | return wantarray ? @result : $result[0]; |
c4d3fae2 |
695 | } |
696 | |
cb6ec758 |
697 | =head2 set_reliable_storage |
698 | |
699 | Sets the current $schema to be 'reliable', that is all queries, both read and |
700 | write are sent to the master |
d4daee7b |
701 | |
cb6ec758 |
702 | =cut |
703 | |
704 | sub set_reliable_storage { |
64cdad22 |
705 | my $self = shift @_; |
706 | my $schema = $self->schema; |
707 | my $write_handler = $self->schema->storage->write_handler; |
d4daee7b |
708 | |
64cdad22 |
709 | $schema->storage->read_handler($write_handler); |
cb6ec758 |
710 | } |
711 | |
712 | =head2 set_balanced_storage |
713 | |
714 | Sets the current $schema to be use the </balancer> for all reads, while all |
48580715 |
715 | writes are sent to the master only |
d4daee7b |
716 | |
cb6ec758 |
717 | =cut |
718 | |
719 | sub set_balanced_storage { |
64cdad22 |
720 | my $self = shift @_; |
721 | my $schema = $self->schema; |
bd5da369 |
722 | my $balanced_handler = $self->schema->storage->balancer; |
d4daee7b |
723 | |
bd5da369 |
724 | $schema->storage->read_handler($balanced_handler); |
cb6ec758 |
725 | } |
2bf79155 |
726 | |
727 | =head2 connected |
728 | |
729 | Check that the master and at least one of the replicants is connected. |
730 | |
731 | =cut |
732 | |
733 | sub connected { |
64cdad22 |
734 | my $self = shift @_; |
735 | return |
736 | $self->master->connected && |
737 | $self->pool->connected_replicants; |
2bf79155 |
738 | } |
739 | |
2bf79155 |
740 | =head2 ensure_connected |
741 | |
742 | Make sure all the storages are connected. |
743 | |
744 | =cut |
745 | |
746 | sub ensure_connected { |
64cdad22 |
747 | my $self = shift @_; |
748 | foreach my $source ($self->all_storages) { |
749 | $source->ensure_connected(@_); |
750 | } |
2bf79155 |
751 | } |
752 | |
2bf79155 |
753 | =head2 limit_dialect |
754 | |
755 | Set the limit_dialect for all existing storages |
756 | |
757 | =cut |
758 | |
759 | sub limit_dialect { |
64cdad22 |
760 | my $self = shift @_; |
761 | foreach my $source ($self->all_storages) { |
762 | $source->limit_dialect(@_); |
763 | } |
f3e9f010 |
764 | return $self->master->limit_dialect; |
2bf79155 |
765 | } |
766 | |
2bf79155 |
767 | =head2 quote_char |
768 | |
769 | Set the quote_char for all existing storages |
770 | |
771 | =cut |
772 | |
773 | sub quote_char { |
64cdad22 |
774 | my $self = shift @_; |
775 | foreach my $source ($self->all_storages) { |
776 | $source->quote_char(@_); |
777 | } |
3fbe08e3 |
778 | return $self->master->quote_char; |
2bf79155 |
779 | } |
780 | |
2bf79155 |
781 | =head2 name_sep |
782 | |
783 | Set the name_sep for all existing storages |
784 | |
785 | =cut |
786 | |
787 | sub name_sep { |
64cdad22 |
788 | my $self = shift @_; |
789 | foreach my $source ($self->all_storages) { |
790 | $source->name_sep(@_); |
791 | } |
3fbe08e3 |
792 | return $self->master->name_sep; |
2bf79155 |
793 | } |
794 | |
2bf79155 |
795 | =head2 set_schema |
796 | |
797 | Set the schema object for all existing storages |
798 | |
799 | =cut |
800 | |
801 | sub set_schema { |
64cdad22 |
802 | my $self = shift @_; |
803 | foreach my $source ($self->all_storages) { |
804 | $source->set_schema(@_); |
805 | } |
2bf79155 |
806 | } |
807 | |
2bf79155 |
808 | =head2 debug |
809 | |
810 | set a debug flag across all storages |
811 | |
812 | =cut |
813 | |
814 | sub debug { |
64cdad22 |
815 | my $self = shift @_; |
3fbe08e3 |
816 | if(@_) { |
817 | foreach my $source ($self->all_storages) { |
818 | $source->debug(@_); |
6f7344b8 |
819 | } |
64cdad22 |
820 | } |
3fbe08e3 |
821 | return $self->master->debug; |
2bf79155 |
822 | } |
823 | |
2bf79155 |
824 | =head2 debugobj |
825 | |
cea43436 |
826 | set a debug object |
2bf79155 |
827 | |
828 | =cut |
829 | |
830 | sub debugobj { |
64cdad22 |
831 | my $self = shift @_; |
cea43436 |
832 | return $self->master->debugobj(@_); |
2bf79155 |
833 | } |
834 | |
2bf79155 |
835 | =head2 debugfh |
836 | |
cea43436 |
837 | set a debugfh object |
2bf79155 |
838 | |
839 | =cut |
840 | |
841 | sub debugfh { |
64cdad22 |
842 | my $self = shift @_; |
cea43436 |
843 | return $self->master->debugfh(@_); |
2bf79155 |
844 | } |
845 | |
2bf79155 |
846 | =head2 debugcb |
847 | |
cea43436 |
848 | set a debug callback |
2bf79155 |
849 | |
850 | =cut |
851 | |
852 | sub debugcb { |
64cdad22 |
853 | my $self = shift @_; |
cea43436 |
854 | return $self->master->debugcb(@_); |
2bf79155 |
855 | } |
856 | |
2bf79155 |
857 | =head2 disconnect |
858 | |
859 | disconnect everything |
860 | |
861 | =cut |
862 | |
863 | sub disconnect { |
64cdad22 |
864 | my $self = shift @_; |
865 | foreach my $source ($self->all_storages) { |
866 | $source->disconnect(@_); |
867 | } |
2bf79155 |
868 | } |
869 | |
b2e4d522 |
870 | =head2 cursor_class |
871 | |
872 | set cursor class on all storages, or return master's |
873 | |
874 | =cut |
875 | |
876 | sub cursor_class { |
877 | my ($self, $cursor_class) = @_; |
878 | |
879 | if ($cursor_class) { |
880 | $_->cursor_class($cursor_class) for $self->all_storages; |
881 | } |
882 | $self->master->cursor_class; |
883 | } |
d4daee7b |
884 | |
3244fdcc |
885 | =head2 cursor |
886 | |
887 | set cursor class on all storages, or return master's, alias for L</cursor_class> |
888 | above. |
889 | |
890 | =cut |
891 | |
892 | sub cursor { |
893 | my ($self, $cursor_class) = @_; |
894 | |
895 | if ($cursor_class) { |
896 | $_->cursor($cursor_class) for $self->all_storages; |
897 | } |
898 | $self->master->cursor; |
899 | } |
900 | |
901 | =head2 unsafe |
902 | |
903 | sets the L<DBIx::Class::Storage::DBI/unsafe> option on all storages or returns |
904 | master's current setting |
905 | |
906 | =cut |
907 | |
908 | sub unsafe { |
909 | my $self = shift; |
910 | |
911 | if (@_) { |
912 | $_->unsafe(@_) for $self->all_storages; |
913 | } |
914 | |
915 | return $self->master->unsafe; |
916 | } |
917 | |
918 | =head2 disable_sth_caching |
919 | |
920 | sets the L<DBIx::Class::Storage::DBI/disable_sth_caching> option on all storages |
921 | or returns master's current setting |
922 | |
923 | =cut |
924 | |
925 | sub disable_sth_caching { |
926 | my $self = shift; |
927 | |
928 | if (@_) { |
929 | $_->disable_sth_caching(@_) for $self->all_storages; |
930 | } |
931 | |
932 | return $self->master->disable_sth_caching; |
933 | } |
934 | |
935 | =head2 lag_behind_master |
936 | |
937 | returns the highest Replicant L<DBIx::Class::Storage::DBI/lag_behind_master> |
938 | setting |
939 | |
940 | =cut |
941 | |
942 | sub lag_behind_master { |
943 | my $self = shift; |
944 | |
945 | return max map $_->lag_behind_master, $self->replicants; |
fd323bf1 |
946 | } |
3244fdcc |
947 | |
948 | =head2 is_replicating |
949 | |
950 | returns true if all replicants return true for |
951 | L<DBIx::Class::Storage::DBI/is_replicating> |
952 | |
953 | =cut |
954 | |
955 | sub is_replicating { |
956 | my $self = shift; |
957 | |
958 | return (grep $_->is_replicating, $self->replicants) == ($self->replicants); |
959 | } |
960 | |
961 | =head2 connect_call_datetime_setup |
962 | |
963 | calls L<DBIx::Class::Storage::DBI/connect_call_datetime_setup> for all storages |
964 | |
965 | =cut |
966 | |
967 | sub connect_call_datetime_setup { |
968 | my $self = shift; |
969 | $_->connect_call_datetime_setup for $self->all_storages; |
970 | } |
971 | |
972 | sub _populate_dbh { |
973 | my $self = shift; |
974 | $_->_populate_dbh for $self->all_storages; |
975 | } |
976 | |
977 | sub _connect { |
978 | my $self = shift; |
979 | $_->_connect for $self->all_storages; |
980 | } |
981 | |
982 | sub _rebless { |
983 | my $self = shift; |
984 | $_->_rebless for $self->all_storages; |
985 | } |
986 | |
987 | sub _determine_driver { |
988 | my $self = shift; |
989 | $_->_determine_driver for $self->all_storages; |
990 | } |
991 | |
992 | sub _driver_determined { |
993 | my $self = shift; |
fd323bf1 |
994 | |
3244fdcc |
995 | if (@_) { |
996 | $_->_driver_determined(@_) for $self->all_storages; |
997 | } |
998 | |
999 | return $self->master->_driver_determined; |
1000 | } |
1001 | |
1002 | sub _init { |
1003 | my $self = shift; |
fd323bf1 |
1004 | |
3244fdcc |
1005 | $_->_init for $self->all_storages; |
1006 | } |
1007 | |
1008 | sub _run_connection_actions { |
1009 | my $self = shift; |
fd323bf1 |
1010 | |
3244fdcc |
1011 | $_->_run_connection_actions for $self->all_storages; |
1012 | } |
1013 | |
1014 | sub _do_connection_actions { |
1015 | my $self = shift; |
fd323bf1 |
1016 | |
3244fdcc |
1017 | if (@_) { |
1018 | $_->_do_connection_actions(@_) for $self->all_storages; |
1019 | } |
1020 | } |
1021 | |
1022 | sub connect_call_do_sql { |
1023 | my $self = shift; |
1024 | $_->connect_call_do_sql(@_) for $self->all_storages; |
1025 | } |
1026 | |
1027 | sub disconnect_call_do_sql { |
1028 | my $self = shift; |
1029 | $_->disconnect_call_do_sql(@_) for $self->all_storages; |
1030 | } |
1031 | |
1032 | sub _seems_connected { |
1033 | my $self = shift; |
1034 | |
1035 | return min map $_->_seems_connected, $self->all_storages; |
1036 | } |
1037 | |
1038 | sub _ping { |
1039 | my $self = shift; |
1040 | |
1041 | return min map $_->_ping, $self->all_storages; |
1042 | } |
1043 | |
bbdda281 |
1044 | # not using the normalized_version, because we want to preserve |
1045 | # version numbers much longer than the conventional xxx.yyyzzz |
7da56142 |
1046 | my $numify_ver = sub { |
1047 | my $ver = shift; |
1048 | my @numparts = split /\D+/, $ver; |
bbdda281 |
1049 | my $format = '%d.' . (join '', ('%06d') x (@numparts - 1)); |
7da56142 |
1050 | |
1051 | return sprintf $format, @numparts; |
1052 | }; |
fecb38cb |
1053 | sub _server_info { |
1054 | my $self = shift; |
1055 | |
bbdda281 |
1056 | if (not $self->_dbh_details->{info}) { |
1057 | $self->_dbh_details->{info} = ( |
fd323bf1 |
1058 | reduce { $a->[0] < $b->[0] ? $a : $b } |
7da56142 |
1059 | map [ $numify_ver->($_->{dbms_version}), $_ ], |
1060 | map $_->_server_info, $self->all_storages |
1061 | )->[1]; |
fecb38cb |
1062 | } |
1063 | |
bbdda281 |
1064 | return $self->next::method; |
fecb38cb |
1065 | } |
1066 | |
1067 | sub _get_server_version { |
1068 | my $self = shift; |
1069 | |
1070 | return $self->_server_info->{dbms_version}; |
1071 | } |
1072 | |
7e38d850 |
1073 | =head1 GOTCHAS |
1074 | |
1075 | Due to the fact that replicants can lag behind a master, you must take care to |
1076 | make sure you use one of the methods to force read queries to a master should |
1077 | you need realtime data integrity. For example, if you insert a row, and then |
1078 | immediately re-read it from the database (say, by doing $row->discard_changes) |
1079 | or you insert a row and then immediately build a query that expects that row |
1080 | to be an item, you should force the master to handle reads. Otherwise, due to |
1081 | the lag, there is no certainty your data will be in the expected state. |
1082 | |
1083 | For data integrity, all transactions automatically use the master storage for |
1084 | all read and write queries. Using a transaction is the preferred and recommended |
1085 | method to force the master to handle all read queries. |
1086 | |
1087 | Otherwise, you can force a single query to use the master with the 'force_pool' |
1088 | attribute: |
1089 | |
1090 | my $row = $resultset->search(undef, {force_pool=>'master'})->find($pk); |
1091 | |
1092 | This attribute will safely be ignore by non replicated storages, so you can use |
1093 | the same code for both types of systems. |
1094 | |
1095 | Lastly, you can use the L</execute_reliably> method, which works very much like |
1096 | a transaction. |
1097 | |
1098 | For debugging, you can turn replication on/off with the methods L</set_reliable_storage> |
1099 | and L</set_balanced_storage>, however this operates at a global level and is not |
1100 | suitable if you have a shared Schema object being used by multiple processes, |
1101 | such as on a web application server. You can get around this limitation by |
1102 | using the Schema clone method. |
1103 | |
1104 | my $new_schema = $schema->clone; |
1105 | $new_schema->set_reliable_storage; |
d4daee7b |
1106 | |
7e38d850 |
1107 | ## $new_schema will use only the Master storage for all reads/writes while |
1108 | ## the $schema object will use replicated storage. |
1109 | |
f5d3a5de |
1110 | =head1 AUTHOR |
1111 | |
0bbe6676 |
1112 | John Napiorkowski <jjnapiork@cpan.org> |
f5d3a5de |
1113 | |
c4d3fae2 |
1114 | Based on code originated by: |
f5d3a5de |
1115 | |
64cdad22 |
1116 | Norbert Csongrádi <bert@cpan.org> |
1117 | Peter Siklósi <einon@einon.hu> |
2156bbdd |
1118 | |
f5d3a5de |
1119 | =head1 LICENSE |
1120 | |
1121 | You may distribute this code under the same terms as Perl itself. |
1122 | |
1123 | =cut |
1124 | |
1125 | 1; |