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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" ) |
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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; |
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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 | |
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23 | =encoding utf8 |
24 | |
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25 | =head1 NAME |
26 | |
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27 | DBIx::Class::Storage::DBI::Replicated - BETA Replicated database support |
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28 | |
29 | =head1 SYNOPSIS |
30 | |
31 | The Following example shows how to change an existing $schema to a replicated |
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32 | storage type, add some replicated (read-only) databases, and perform reporting |
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33 | tasks. |
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34 | |
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35 | You should set the 'storage_type attribute to a replicated type. You should |
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36 | also define your arguments, such as which balancer you want and any arguments |
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37 | that the Pool object should get. |
38 | |
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39 | my $schema = Schema::Class->clone; |
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40 | $schema->storage_type( ['::DBI::Replicated', {balancer=>'::Random'}] ); |
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41 | $schema->connection(...); |
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42 | |
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43 | Next, you need to add in the Replicants. Basically this is an array of |
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44 | arrayrefs, where each arrayref is database connect information. Think of these |
45 | arguments as what you'd pass to the 'normal' $schema->connect method. |
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46 | |
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47 | $schema->storage->connect_replicants( |
48 | [$dsn1, $user, $pass, \%opts], |
49 | [$dsn2, $user, $pass, \%opts], |
50 | [$dsn3, $user, $pass, \%opts], |
51 | ); |
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52 | |
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53 | Now, just use the $schema as you normally would. Automatically all reads will |
54 | be delegated to the replicants, while writes to the master. |
55 | |
7e38d850 |
56 | $schema->resultset('Source')->search({name=>'etc'}); |
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57 | |
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58 | You can force a given query to use a particular storage using the search |
59 | attribute 'force_pool'. For example: |
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60 | |
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61 | my $rs = $schema->resultset('Source')->search(undef, {force_pool=>'master'}); |
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62 | |
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63 | Now $rs will force everything (both reads and writes) to use whatever was setup |
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64 | as the master storage. 'master' is hardcoded to always point to the Master, |
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65 | but you can also use any Replicant name. Please see: |
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66 | L<DBIx::Class::Storage::DBI::Replicated::Pool> and the replicants attribute for more. |
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67 | |
68 | Also see transactions and L</execute_reliably> for alternative ways to |
69 | force read traffic to the master. In general, you should wrap your statements |
70 | in a transaction when you are reading and writing to the same tables at the |
71 | same time, since your replicants will often lag a bit behind the master. |
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72 | |
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73 | If you have a multi-statement read only transaction you can force it to select |
74 | a random server in the pool by: |
75 | |
76 | my $rs = $schema->resultset('Source')->search( undef, |
77 | { force_pool => $db->storage->read_handler->next_storage } |
78 | ); |
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79 | |
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80 | =head1 DESCRIPTION |
81 | |
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82 | Warning: This class is marked BETA. This has been running a production |
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83 | website using MySQL native replication as its backend and we have some decent |
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84 | test coverage but the code hasn't yet been stressed by a variety of databases. |
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85 | Individual DBs may have quirks we are not aware of. Please use this in first |
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86 | development and pass along your experiences/bug fixes. |
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87 | |
88 | This class implements replicated data store for DBI. Currently you can define |
89 | one master and numerous slave database connections. All write-type queries |
90 | (INSERT, UPDATE, DELETE and even LAST_INSERT_ID) are routed to master |
91 | database, all read-type queries (SELECTs) go to the slave database. |
92 | |
93 | Basically, any method request that L<DBIx::Class::Storage::DBI> would normally |
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94 | handle gets delegated to one of the two attributes: L</read_handler> or to |
95 | L</write_handler>. Additionally, some methods need to be distributed |
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96 | to all existing storages. This way our storage class is a drop in replacement |
97 | for L<DBIx::Class::Storage::DBI>. |
98 | |
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99 | Read traffic is spread across the replicants (slaves) occurring to a user |
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100 | selected algorithm. The default algorithm is random weighted. |
101 | |
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102 | =head1 NOTES |
103 | |
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104 | The consistency between master and replicants is database specific. The Pool |
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105 | gives you a method to validate its replicants, removing and replacing them |
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106 | when they fail/pass predefined criteria. Please make careful use of the ways |
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107 | to force a query to run against Master when needed. |
108 | |
109 | =head1 REQUIREMENTS |
110 | |
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111 | Replicated Storage has additional requirements not currently part of |
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112 | L<DBIx::Class>. See L<DBIx::Class::Optional::Dependencies> for more details. |
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113 | |
114 | =head1 ATTRIBUTES |
115 | |
116 | This class defines the following attributes. |
117 | |
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118 | =head2 schema |
119 | |
120 | The underlying L<DBIx::Class::Schema> object this storage is attaching |
121 | |
122 | =cut |
123 | |
124 | has 'schema' => ( |
125 | is=>'rw', |
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126 | isa=>DBICSchema, |
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127 | weak_ref=>1, |
128 | required=>1, |
129 | ); |
130 | |
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131 | =head2 pool_type |
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132 | |
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133 | Contains the classname which will instantiate the L</pool> object. Defaults |
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134 | to: L<DBIx::Class::Storage::DBI::Replicated::Pool>. |
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135 | |
136 | =cut |
137 | |
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138 | has 'pool_type' => ( |
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139 | is=>'rw', |
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140 | isa=>ClassName, |
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141 | default=>'DBIx::Class::Storage::DBI::Replicated::Pool', |
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142 | handles=>{ |
143 | 'create_pool' => 'new', |
144 | }, |
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145 | ); |
146 | |
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147 | =head2 pool_args |
148 | |
149 | Contains a hashref of initialized information to pass to the Balancer object. |
212cc5c2 |
150 | See L<DBIx::Class::Storage::DBI::Replicated::Pool> for available arguments. |
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151 | |
152 | =cut |
153 | |
154 | has 'pool_args' => ( |
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155 | is=>'rw', |
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156 | isa=>HashRef, |
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157 | lazy=>1, |
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158 | default=>sub { {} }, |
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159 | ); |
160 | |
161 | |
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162 | =head2 balancer_type |
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163 | |
164 | The replication pool requires a balance class to provider the methods for |
165 | choose how to spread the query load across each replicant in the pool. |
166 | |
167 | =cut |
168 | |
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169 | has 'balancer_type' => ( |
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170 | is=>'rw', |
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171 | isa=>BalancerClassNamePart, |
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172 | coerce=>1, |
173 | required=>1, |
174 | default=> 'DBIx::Class::Storage::DBI::Replicated::Balancer::First', |
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175 | handles=>{ |
176 | 'create_balancer' => 'new', |
177 | }, |
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178 | ); |
179 | |
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180 | =head2 balancer_args |
181 | |
182 | Contains a hashref of initialized information to pass to the Balancer object. |
212cc5c2 |
183 | See L<DBIx::Class::Storage::DBI::Replicated::Balancer> for available arguments. |
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184 | |
185 | =cut |
186 | |
187 | has 'balancer_args' => ( |
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188 | is=>'rw', |
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189 | isa=>HashRef, |
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190 | lazy=>1, |
191 | required=>1, |
192 | default=>sub { {} }, |
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193 | ); |
194 | |
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195 | =head2 pool |
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196 | |
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197 | Is a L<DBIx::Class::Storage::DBI::Replicated::Pool> or derived class. This is a |
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198 | container class for one or more replicated databases. |
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199 | |
200 | =cut |
201 | |
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202 | has 'pool' => ( |
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203 | is=>'ro', |
204 | isa=>'DBIx::Class::Storage::DBI::Replicated::Pool', |
205 | lazy_build=>1, |
206 | handles=>[qw/ |
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207 | connect_replicants |
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208 | replicants |
209 | has_replicants |
210 | /], |
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211 | ); |
212 | |
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213 | =head2 balancer |
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214 | |
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215 | Is a L<DBIx::Class::Storage::DBI::Replicated::Balancer> or derived class. This |
216 | is a class that takes a pool (L<DBIx::Class::Storage::DBI::Replicated::Pool>) |
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217 | |
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218 | =cut |
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219 | |
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220 | has 'balancer' => ( |
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221 | is=>'rw', |
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222 | isa=>'DBIx::Class::Storage::DBI::Replicated::Balancer', |
223 | lazy_build=>1, |
224 | handles=>[qw/auto_validate_every/], |
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225 | ); |
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226 | |
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227 | =head2 master |
228 | |
229 | The master defines the canonical state for a pool of connected databases. All |
230 | the replicants are expected to match this databases state. Thus, in a classic |
231 | Master / Slaves distributed system, all the slaves are expected to replicate |
232 | the Master's state as quick as possible. This is the only database in the |
233 | pool of databases that is allowed to handle write traffic. |
234 | |
235 | =cut |
236 | |
237 | has 'master' => ( |
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238 | is=> 'ro', |
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239 | isa=>DBICStorageDBI, |
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240 | lazy_build=>1, |
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241 | ); |
242 | |
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243 | =head1 ATTRIBUTES IMPLEMENTING THE DBIx::Storage::DBI INTERFACE |
244 | |
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245 | The following methods are delegated all the methods required for the |
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246 | L<DBIx::Class::Storage::DBI> interface. |
247 | |
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248 | =cut |
249 | |
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250 | my $method_dispatch = { |
251 | writer => [qw/ |
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252 | on_connect_do |
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253 | on_disconnect_do |
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254 | on_connect_call |
255 | on_disconnect_call |
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256 | connect_info |
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257 | _connect_info |
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258 | throw_exception |
259 | sql_maker |
260 | sqlt_type |
261 | create_ddl_dir |
262 | deployment_statements |
263 | datetime_parser |
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264 | datetime_parser_type |
265 | build_datetime_parser |
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266 | last_insert_id |
267 | insert |
268 | insert_bulk |
269 | update |
270 | delete |
271 | dbh |
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272 | txn_begin |
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273 | txn_do |
274 | txn_commit |
275 | txn_rollback |
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276 | txn_scope_guard |
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277 | _exec_txn_rollback |
278 | _exec_txn_begin |
279 | _exec_txn_commit |
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280 | deploy |
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281 | with_deferred_fk_checks |
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282 | dbh_do |
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283 | _prep_for_execute |
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284 | is_datatype_numeric |
285 | _count_select |
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286 | svp_rollback |
287 | svp_begin |
288 | svp_release |
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289 | relname_to_table_alias |
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290 | _dbh_last_insert_id |
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291 | _default_dbi_connect_attributes |
292 | _dbi_connect_info |
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293 | _dbic_connect_attributes |
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294 | auto_savepoint |
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295 | _query_start |
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296 | _query_end |
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297 | _format_for_trace |
298 | _dbi_attrs_for_bind |
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299 | bind_attribute_by_data_type |
300 | transaction_depth |
301 | _dbh |
302 | _select_args |
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303 | _dbh_execute_for_fetch |
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304 | _sql_maker |
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305 | _dbh_execute_inserts_with_no_binds |
306 | _select_args_to_query |
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307 | _gen_sql_bind |
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308 | _svp_generate_name |
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309 | _normalize_connect_info |
310 | _parse_connect_do |
3244fdcc |
311 | savepoints |
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312 | _sql_maker_opts |
313 | _conn_pid |
3244fdcc |
314 | _dbh_autocommit |
315 | _native_data_type |
316 | _get_dbh |
317 | sql_maker_class |
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318 | _execute |
319 | _do_query |
402ac1c9 |
320 | _sth |
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321 | _dbh_sth |
322 | _dbh_execute |
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323 | /, Class::MOP::Class->initialize('DBIx::Class::Storage::DBIHacks')->get_method_list ], |
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324 | reader => [qw/ |
325 | select |
326 | select_single |
327 | columns_info_for |
328 | _dbh_columns_info_for |
329 | _select |
330 | /], |
331 | unimplemented => [qw/ |
332 | _arm_global_destructor |
333 | _verify_pid |
334 | |
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335 | source_bind_attributes |
336 | |
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337 | get_use_dbms_capability |
338 | set_use_dbms_capability |
339 | get_dbms_capability |
340 | set_dbms_capability |
341 | _dbh_details |
342 | _dbh_get_info |
343 | |
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344 | _determine_connector_driver |
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 |
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353 | _perform_autoinc_retrieval |
354 | _autoinc_supplied_for_op |
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355 | |
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356 | _resolve_bindattrs |
357 | |
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358 | _max_column_bytesize |
359 | _is_lob_type |
360 | _is_binary_lob_type |
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361 | _is_binary_type |
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362 | _is_text_lob_type |
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363 | |
364 | sth |
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365 | /,( |
366 | # the capability framework |
367 | # not sure if CMOP->initialize does evil things to DBIC::S::DBI, fix if a problem |
368 | grep |
369 | { $_ =~ /^ _ (?: use | supports | determine_supports ) _ /x } |
370 | ( Class::MOP::Class->initialize('DBIx::Class::Storage::DBI')->get_all_method_names ) |
371 | )], |
372 | }; |
373 | |
374 | if (DBIx::Class::_ENV_::DBICTEST) { |
375 | |
376 | my $seen; |
377 | for my $type (keys %$method_dispatch) { |
378 | for (@{$method_dispatch->{$type}}) { |
379 | push @{$seen->{$_}}, $type; |
380 | } |
381 | } |
cb6ec758 |
382 | |
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383 | if (my @dupes = grep { @{$seen->{$_}} > 1 } keys %$seen) { |
384 | die(join "\n", '', |
385 | 'The following methods show up multiple times in ::Storage::DBI::Replicated handlers:', |
386 | (map { "$_: " . (join ', ', @{$seen->{$_}}) } sort @dupes), |
387 | '', |
388 | ); |
389 | } |
bbdda281 |
390 | |
4bea1fe7 |
391 | if (my @cant = grep { ! DBIx::Class::Storage::DBI->can($_) } keys %$seen) { |
392 | die(join "\n", '', |
393 | '::Storage::DBI::Replicated specifies handling of the following *NON EXISTING* ::Storage::DBI methods:', |
394 | @cant, |
395 | '', |
396 | ); |
397 | } |
398 | } |
bbdda281 |
399 | |
4bea1fe7 |
400 | for my $method (@{$method_dispatch->{unimplemented}}) { |
401 | __PACKAGE__->meta->add_method($method, sub { |
70c28808 |
402 | my $self = shift; |
403 | $self->throw_exception("$method must not be called on ".(blessed $self).' objects'); |
4bea1fe7 |
404 | }); |
405 | } |
31a8aaaf |
406 | |
4bea1fe7 |
407 | =head2 read_handler |
584ea6e4 |
408 | |
4bea1fe7 |
409 | Defines an object that implements the read side of L<BIx::Class::Storage::DBI>. |
584ea6e4 |
410 | |
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411 | =cut |
412 | |
413 | has 'read_handler' => ( |
414 | is=>'rw', |
415 | isa=>Object, |
416 | lazy_build=>1, |
417 | handles=>$method_dispatch->{reader}, |
e471ab87 |
418 | ); |
419 | |
4bea1fe7 |
420 | =head2 write_handler |
421 | |
422 | Defines an object that implements the write side of L<BIx::Class::Storage::DBI>, |
423 | as well as methods that don't write or read that can be called on only one |
424 | storage, methods that return a C<$dbh>, and any methods that don't make sense to |
425 | run on a replicant. |
426 | |
427 | =cut |
428 | |
429 | has 'write_handler' => ( |
430 | is=>'ro', |
431 | isa=>Object, |
432 | lazy_build=>1, |
433 | handles=>$method_dispatch->{writer}, |
7f4433eb |
434 | ); |
435 | |
4bea1fe7 |
436 | |
6d766626 |
437 | |
b2e4d522 |
438 | has _master_connect_info_opts => |
439 | (is => 'rw', isa => HashRef, default => sub { {} }); |
440 | |
441 | =head2 around: connect_info |
442 | |
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443 | Preserves master's C<connect_info> options (for merging with replicants.) |
444 | Also sets any Replicated-related options from connect_info, such as |
dcdf7b2c |
445 | C<pool_type>, C<pool_args>, C<balancer_type> and C<balancer_args>. |
b2e4d522 |
446 | |
447 | =cut |
448 | |
449 | around connect_info => sub { |
450 | my ($next, $self, $info, @extra) = @_; |
451 | |
282a9a4f |
452 | my $merge = Hash::Merge->new('LEFT_PRECEDENT'); |
e666c5fd |
453 | |
b2e4d522 |
454 | my %opts; |
455 | for my $arg (@$info) { |
456 | next unless (reftype($arg)||'') eq 'HASH'; |
e666c5fd |
457 | %opts = %{ $merge->merge($arg, \%opts) }; |
b2e4d522 |
458 | } |
b2e4d522 |
459 | delete $opts{dsn}; |
460 | |
dcdf7b2c |
461 | if (@opts{qw/pool_type pool_args/}) { |
462 | $self->pool_type(delete $opts{pool_type}) |
463 | if $opts{pool_type}; |
464 | |
b88b85e7 |
465 | $self->pool_args( |
e666c5fd |
466 | $merge->merge((delete $opts{pool_args} || {}), $self->pool_args) |
b88b85e7 |
467 | ); |
dcdf7b2c |
468 | |
64ae1667 |
469 | ## Since we possibly changed the pool_args, we need to clear the current |
470 | ## pool object so that next time it is used it will be rebuilt. |
471 | $self->clear_pool; |
dcdf7b2c |
472 | } |
473 | |
474 | if (@opts{qw/balancer_type balancer_args/}) { |
475 | $self->balancer_type(delete $opts{balancer_type}) |
476 | if $opts{balancer_type}; |
477 | |
b88b85e7 |
478 | $self->balancer_args( |
e666c5fd |
479 | $merge->merge((delete $opts{balancer_args} || {}), $self->balancer_args) |
b88b85e7 |
480 | ); |
dcdf7b2c |
481 | |
67c43863 |
482 | $self->balancer($self->_build_balancer) |
6f7344b8 |
483 | if $self->balancer; |
dcdf7b2c |
484 | } |
485 | |
b2e4d522 |
486 | $self->_master_connect_info_opts(\%opts); |
487 | |
1abccf54 |
488 | return preserve_context { |
489 | $self->$next($info, @extra); |
490 | } after => sub { |
491 | # Make sure master is blessed into the correct class and apply role to it. |
492 | my $master = $self->master; |
493 | $master->_determine_driver; |
494 | Moose::Meta::Class->initialize(ref $master); |
cea43436 |
495 | |
1abccf54 |
496 | DBIx::Class::Storage::DBI::Replicated::WithDSN->meta->apply($master); |
0ce2d0d5 |
497 | |
1abccf54 |
498 | # link pool back to master |
499 | $self->pool->master($master); |
500 | }; |
b2e4d522 |
501 | }; |
502 | |
26ab719a |
503 | =head1 METHODS |
2bf79155 |
504 | |
26ab719a |
505 | This class defines the following methods. |
2bf79155 |
506 | |
c354902c |
507 | =head2 BUILDARGS |
2bf79155 |
508 | |
faaba25f |
509 | L<DBIx::Class::Schema> when instantiating its storage passed itself as the |
2ce6e9a6 |
510 | first argument. So we need to massage the arguments a bit so that all the |
511 | bits get put into the correct places. |
2bf79155 |
512 | |
513 | =cut |
514 | |
c354902c |
515 | sub BUILDARGS { |
fd323bf1 |
516 | my ($class, $schema, $storage_type_args, @args) = @_; |
d4daee7b |
517 | |
c354902c |
518 | return { |
6f7344b8 |
519 | schema=>$schema, |
520 | %$storage_type_args, |
521 | @args |
c354902c |
522 | } |
523 | } |
2bf79155 |
524 | |
cb6ec758 |
525 | =head2 _build_master |
2bf79155 |
526 | |
cb6ec758 |
527 | Lazy builder for the L</master> attribute. |
2bf79155 |
528 | |
529 | =cut |
530 | |
cb6ec758 |
531 | sub _build_master { |
2ce6e9a6 |
532 | my $self = shift @_; |
ee356d00 |
533 | my $master = DBIx::Class::Storage::DBI->new($self->schema); |
ee356d00 |
534 | $master |
106d5f3b |
535 | } |
536 | |
26ab719a |
537 | =head2 _build_pool |
2bf79155 |
538 | |
26ab719a |
539 | Lazy builder for the L</pool> attribute. |
2bf79155 |
540 | |
541 | =cut |
542 | |
26ab719a |
543 | sub _build_pool { |
64cdad22 |
544 | my $self = shift @_; |
545 | $self->create_pool(%{$self->pool_args}); |
2bf79155 |
546 | } |
547 | |
26ab719a |
548 | =head2 _build_balancer |
2bf79155 |
549 | |
cb6ec758 |
550 | Lazy builder for the L</balancer> attribute. This takes a Pool object so that |
551 | the balancer knows which pool it's balancing. |
2bf79155 |
552 | |
553 | =cut |
554 | |
26ab719a |
555 | sub _build_balancer { |
64cdad22 |
556 | my $self = shift @_; |
557 | $self->create_balancer( |
6f7344b8 |
558 | pool=>$self->pool, |
64cdad22 |
559 | master=>$self->master, |
560 | %{$self->balancer_args}, |
561 | ); |
2bf79155 |
562 | } |
563 | |
cb6ec758 |
564 | =head2 _build_write_handler |
2bf79155 |
565 | |
cb6ec758 |
566 | Lazy builder for the L</write_handler> attribute. The default is to set this to |
567 | the L</master>. |
50336325 |
568 | |
569 | =cut |
570 | |
cb6ec758 |
571 | sub _build_write_handler { |
64cdad22 |
572 | return shift->master; |
cb6ec758 |
573 | } |
50336325 |
574 | |
cb6ec758 |
575 | =head2 _build_read_handler |
2bf79155 |
576 | |
cb6ec758 |
577 | Lazy builder for the L</read_handler> attribute. The default is to set this to |
578 | the L</balancer>. |
2bf79155 |
579 | |
580 | =cut |
581 | |
cb6ec758 |
582 | sub _build_read_handler { |
64cdad22 |
583 | return shift->balancer; |
cb6ec758 |
584 | } |
50336325 |
585 | |
cb6ec758 |
586 | =head2 around: connect_replicants |
2bf79155 |
587 | |
cb6ec758 |
588 | All calls to connect_replicants needs to have an existing $schema tacked onto |
b2e4d522 |
589 | top of the args, since L<DBIx::Storage::DBI> needs it, and any C<connect_info> |
590 | options merged with the master, with replicant opts having higher priority. |
955a6df6 |
591 | |
cb6ec758 |
592 | =cut |
955a6df6 |
593 | |
b2e4d522 |
594 | around connect_replicants => sub { |
595 | my ($next, $self, @args) = @_; |
596 | |
597 | for my $r (@args) { |
598 | $r = [ $r ] unless reftype $r eq 'ARRAY'; |
599 | |
1a58752c |
600 | $self->throw_exception('coderef replicant connect_info not supported') |
b2e4d522 |
601 | if ref $r->[0] && reftype $r->[0] eq 'CODE'; |
602 | |
603 | # any connect_info options? |
604 | my $i = 0; |
605 | $i++ while $i < @$r && (reftype($r->[$i])||'') ne 'HASH'; |
606 | |
6f7344b8 |
607 | # make one if none |
b2e4d522 |
608 | $r->[$i] = {} unless $r->[$i]; |
609 | |
610 | # merge if two hashes |
b88b85e7 |
611 | my @hashes = @$r[$i .. $#{$r}]; |
612 | |
1a58752c |
613 | $self->throw_exception('invalid connect_info options') |
b88b85e7 |
614 | if (grep { reftype($_) eq 'HASH' } @hashes) != @hashes; |
615 | |
1a58752c |
616 | $self->throw_exception('too many hashrefs in connect_info') |
b88b85e7 |
617 | if @hashes > 2; |
618 | |
282a9a4f |
619 | my $merge = Hash::Merge->new('LEFT_PRECEDENT'); |
e666c5fd |
620 | my %opts = %{ $merge->merge(reverse @hashes) }; |
b88b85e7 |
621 | |
622 | # delete them |
b2e4d522 |
623 | splice @$r, $i+1, ($#{$r} - $i), (); |
624 | |
0bd8e058 |
625 | # make sure master/replicants opts don't clash |
626 | my %master_opts = %{ $self->_master_connect_info_opts }; |
627 | if (exists $opts{dbh_maker}) { |
628 | delete @master_opts{qw/dsn user password/}; |
629 | } |
630 | delete $master_opts{dbh_maker}; |
631 | |
b2e4d522 |
632 | # merge with master |
e666c5fd |
633 | %opts = %{ $merge->merge(\%opts, \%master_opts) }; |
b2e4d522 |
634 | |
635 | # update |
636 | $r->[$i] = \%opts; |
637 | } |
638 | |
639 | $self->$next($self->schema, @args); |
955a6df6 |
640 | }; |
2bf79155 |
641 | |
2bf79155 |
642 | =head2 all_storages |
643 | |
644 | Returns an array of of all the connected storage backends. The first element |
645 | in the returned array is the master, and the remainings are each of the |
646 | replicants. |
647 | |
648 | =cut |
649 | |
650 | sub all_storages { |
64cdad22 |
651 | my $self = shift @_; |
652 | return grep {defined $_ && blessed $_} ( |
653 | $self->master, |
6412a592 |
654 | values %{ $self->replicants }, |
64cdad22 |
655 | ); |
2bf79155 |
656 | } |
657 | |
c4d3fae2 |
658 | =head2 execute_reliably ($coderef, ?@args) |
659 | |
660 | Given a coderef, saves the current state of the L</read_handler>, forces it to |
48580715 |
661 | use reliable storage (e.g. sets it to the master), executes a coderef and then |
c4d3fae2 |
662 | restores the original state. |
663 | |
664 | Example: |
665 | |
64cdad22 |
666 | my $reliably = sub { |
667 | my $name = shift @_; |
668 | $schema->resultset('User')->create({name=>$name}); |
fd323bf1 |
669 | my $user_rs = $schema->resultset('User')->find({name=>$name}); |
64cdad22 |
670 | return $user_rs; |
671 | }; |
c4d3fae2 |
672 | |
64cdad22 |
673 | my $user_rs = $schema->storage->execute_reliably($reliably, 'John'); |
c4d3fae2 |
674 | |
675 | Use this when you must be certain of your database state, such as when you just |
676 | inserted something and need to get a resultset including it, etc. |
677 | |
678 | =cut |
679 | |
680 | sub execute_reliably { |
1abccf54 |
681 | my $self = shift; |
682 | my $coderef = shift; |
d4daee7b |
683 | |
64cdad22 |
684 | unless( ref $coderef eq 'CODE') { |
685 | $self->throw_exception('Second argument must be a coderef'); |
686 | } |
d4daee7b |
687 | |
1abccf54 |
688 | ## replace the current read handler for the remainder of the scope |
689 | local $self->{read_handler} = $self->master; |
d4daee7b |
690 | |
1abccf54 |
691 | my $args = \@_; |
692 | return try { |
693 | $coderef->(@$args); |
ed7ab0f4 |
694 | } catch { |
695 | $self->throw_exception("coderef returned an error: $_"); |
64cdad22 |
696 | }; |
c4d3fae2 |
697 | } |
698 | |
cb6ec758 |
699 | =head2 set_reliable_storage |
700 | |
701 | Sets the current $schema to be 'reliable', that is all queries, both read and |
702 | write are sent to the master |
d4daee7b |
703 | |
cb6ec758 |
704 | =cut |
705 | |
706 | sub set_reliable_storage { |
64cdad22 |
707 | my $self = shift @_; |
708 | my $schema = $self->schema; |
709 | my $write_handler = $self->schema->storage->write_handler; |
d4daee7b |
710 | |
64cdad22 |
711 | $schema->storage->read_handler($write_handler); |
cb6ec758 |
712 | } |
713 | |
714 | =head2 set_balanced_storage |
715 | |
716 | Sets the current $schema to be use the </balancer> for all reads, while all |
48580715 |
717 | writes are sent to the master only |
d4daee7b |
718 | |
cb6ec758 |
719 | =cut |
720 | |
721 | sub set_balanced_storage { |
64cdad22 |
722 | my $self = shift @_; |
723 | my $schema = $self->schema; |
bd5da369 |
724 | my $balanced_handler = $self->schema->storage->balancer; |
d4daee7b |
725 | |
bd5da369 |
726 | $schema->storage->read_handler($balanced_handler); |
cb6ec758 |
727 | } |
2bf79155 |
728 | |
729 | =head2 connected |
730 | |
731 | Check that the master and at least one of the replicants is connected. |
732 | |
733 | =cut |
734 | |
735 | sub connected { |
64cdad22 |
736 | my $self = shift @_; |
737 | return |
738 | $self->master->connected && |
739 | $self->pool->connected_replicants; |
2bf79155 |
740 | } |
741 | |
2bf79155 |
742 | =head2 ensure_connected |
743 | |
744 | Make sure all the storages are connected. |
745 | |
746 | =cut |
747 | |
748 | sub ensure_connected { |
64cdad22 |
749 | my $self = shift @_; |
750 | foreach my $source ($self->all_storages) { |
751 | $source->ensure_connected(@_); |
752 | } |
2bf79155 |
753 | } |
754 | |
2bf79155 |
755 | =head2 limit_dialect |
756 | |
757 | Set the limit_dialect for all existing storages |
758 | |
759 | =cut |
760 | |
761 | sub limit_dialect { |
64cdad22 |
762 | my $self = shift @_; |
763 | foreach my $source ($self->all_storages) { |
764 | $source->limit_dialect(@_); |
765 | } |
f3e9f010 |
766 | return $self->master->limit_dialect; |
2bf79155 |
767 | } |
768 | |
2bf79155 |
769 | =head2 quote_char |
770 | |
771 | Set the quote_char for all existing storages |
772 | |
773 | =cut |
774 | |
775 | sub quote_char { |
64cdad22 |
776 | my $self = shift @_; |
777 | foreach my $source ($self->all_storages) { |
778 | $source->quote_char(@_); |
779 | } |
3fbe08e3 |
780 | return $self->master->quote_char; |
2bf79155 |
781 | } |
782 | |
2bf79155 |
783 | =head2 name_sep |
784 | |
785 | Set the name_sep for all existing storages |
786 | |
787 | =cut |
788 | |
789 | sub name_sep { |
64cdad22 |
790 | my $self = shift @_; |
791 | foreach my $source ($self->all_storages) { |
792 | $source->name_sep(@_); |
793 | } |
3fbe08e3 |
794 | return $self->master->name_sep; |
2bf79155 |
795 | } |
796 | |
2bf79155 |
797 | =head2 set_schema |
798 | |
799 | Set the schema object for all existing storages |
800 | |
801 | =cut |
802 | |
803 | sub set_schema { |
64cdad22 |
804 | my $self = shift @_; |
805 | foreach my $source ($self->all_storages) { |
806 | $source->set_schema(@_); |
807 | } |
2bf79155 |
808 | } |
809 | |
2bf79155 |
810 | =head2 debug |
811 | |
812 | set a debug flag across all storages |
813 | |
814 | =cut |
815 | |
816 | sub debug { |
64cdad22 |
817 | my $self = shift @_; |
3fbe08e3 |
818 | if(@_) { |
819 | foreach my $source ($self->all_storages) { |
820 | $source->debug(@_); |
6f7344b8 |
821 | } |
64cdad22 |
822 | } |
3fbe08e3 |
823 | return $self->master->debug; |
2bf79155 |
824 | } |
825 | |
2bf79155 |
826 | =head2 debugobj |
827 | |
cea43436 |
828 | set a debug object |
2bf79155 |
829 | |
830 | =cut |
831 | |
832 | sub debugobj { |
64cdad22 |
833 | my $self = shift @_; |
cea43436 |
834 | return $self->master->debugobj(@_); |
2bf79155 |
835 | } |
836 | |
2bf79155 |
837 | =head2 debugfh |
838 | |
cea43436 |
839 | set a debugfh object |
2bf79155 |
840 | |
841 | =cut |
842 | |
843 | sub debugfh { |
64cdad22 |
844 | my $self = shift @_; |
cea43436 |
845 | return $self->master->debugfh(@_); |
2bf79155 |
846 | } |
847 | |
2bf79155 |
848 | =head2 debugcb |
849 | |
cea43436 |
850 | set a debug callback |
2bf79155 |
851 | |
852 | =cut |
853 | |
854 | sub debugcb { |
64cdad22 |
855 | my $self = shift @_; |
cea43436 |
856 | return $self->master->debugcb(@_); |
2bf79155 |
857 | } |
858 | |
2bf79155 |
859 | =head2 disconnect |
860 | |
861 | disconnect everything |
862 | |
863 | =cut |
864 | |
865 | sub disconnect { |
64cdad22 |
866 | my $self = shift @_; |
867 | foreach my $source ($self->all_storages) { |
868 | $source->disconnect(@_); |
869 | } |
2bf79155 |
870 | } |
871 | |
b2e4d522 |
872 | =head2 cursor_class |
873 | |
874 | set cursor class on all storages, or return master's |
875 | |
876 | =cut |
877 | |
878 | sub cursor_class { |
879 | my ($self, $cursor_class) = @_; |
880 | |
881 | if ($cursor_class) { |
882 | $_->cursor_class($cursor_class) for $self->all_storages; |
883 | } |
884 | $self->master->cursor_class; |
885 | } |
d4daee7b |
886 | |
3244fdcc |
887 | =head2 cursor |
888 | |
889 | set cursor class on all storages, or return master's, alias for L</cursor_class> |
890 | above. |
891 | |
892 | =cut |
893 | |
894 | sub cursor { |
895 | my ($self, $cursor_class) = @_; |
896 | |
897 | if ($cursor_class) { |
898 | $_->cursor($cursor_class) for $self->all_storages; |
899 | } |
900 | $self->master->cursor; |
901 | } |
902 | |
903 | =head2 unsafe |
904 | |
905 | sets the L<DBIx::Class::Storage::DBI/unsafe> option on all storages or returns |
906 | master's current setting |
907 | |
908 | =cut |
909 | |
910 | sub unsafe { |
911 | my $self = shift; |
912 | |
913 | if (@_) { |
914 | $_->unsafe(@_) for $self->all_storages; |
915 | } |
916 | |
917 | return $self->master->unsafe; |
918 | } |
919 | |
920 | =head2 disable_sth_caching |
921 | |
922 | sets the L<DBIx::Class::Storage::DBI/disable_sth_caching> option on all storages |
923 | or returns master's current setting |
924 | |
925 | =cut |
926 | |
927 | sub disable_sth_caching { |
928 | my $self = shift; |
929 | |
930 | if (@_) { |
931 | $_->disable_sth_caching(@_) for $self->all_storages; |
932 | } |
933 | |
934 | return $self->master->disable_sth_caching; |
935 | } |
936 | |
937 | =head2 lag_behind_master |
938 | |
939 | returns the highest Replicant L<DBIx::Class::Storage::DBI/lag_behind_master> |
940 | setting |
941 | |
942 | =cut |
943 | |
944 | sub lag_behind_master { |
945 | my $self = shift; |
946 | |
947 | return max map $_->lag_behind_master, $self->replicants; |
fd323bf1 |
948 | } |
3244fdcc |
949 | |
950 | =head2 is_replicating |
951 | |
952 | returns true if all replicants return true for |
953 | L<DBIx::Class::Storage::DBI/is_replicating> |
954 | |
955 | =cut |
956 | |
957 | sub is_replicating { |
958 | my $self = shift; |
959 | |
960 | return (grep $_->is_replicating, $self->replicants) == ($self->replicants); |
961 | } |
962 | |
963 | =head2 connect_call_datetime_setup |
964 | |
965 | calls L<DBIx::Class::Storage::DBI/connect_call_datetime_setup> for all storages |
966 | |
967 | =cut |
968 | |
969 | sub connect_call_datetime_setup { |
970 | my $self = shift; |
971 | $_->connect_call_datetime_setup for $self->all_storages; |
972 | } |
973 | |
974 | sub _populate_dbh { |
975 | my $self = shift; |
976 | $_->_populate_dbh for $self->all_storages; |
977 | } |
978 | |
979 | sub _connect { |
980 | my $self = shift; |
981 | $_->_connect for $self->all_storages; |
982 | } |
983 | |
984 | sub _rebless { |
985 | my $self = shift; |
986 | $_->_rebless for $self->all_storages; |
987 | } |
988 | |
989 | sub _determine_driver { |
990 | my $self = shift; |
991 | $_->_determine_driver for $self->all_storages; |
992 | } |
993 | |
994 | sub _driver_determined { |
995 | my $self = shift; |
fd323bf1 |
996 | |
3244fdcc |
997 | if (@_) { |
998 | $_->_driver_determined(@_) for $self->all_storages; |
999 | } |
1000 | |
1001 | return $self->master->_driver_determined; |
1002 | } |
1003 | |
1004 | sub _init { |
1005 | my $self = shift; |
fd323bf1 |
1006 | |
3244fdcc |
1007 | $_->_init for $self->all_storages; |
1008 | } |
1009 | |
1010 | sub _run_connection_actions { |
1011 | my $self = shift; |
fd323bf1 |
1012 | |
3244fdcc |
1013 | $_->_run_connection_actions for $self->all_storages; |
1014 | } |
1015 | |
1016 | sub _do_connection_actions { |
1017 | my $self = shift; |
fd323bf1 |
1018 | |
3244fdcc |
1019 | if (@_) { |
1020 | $_->_do_connection_actions(@_) for $self->all_storages; |
1021 | } |
1022 | } |
1023 | |
1024 | sub connect_call_do_sql { |
1025 | my $self = shift; |
1026 | $_->connect_call_do_sql(@_) for $self->all_storages; |
1027 | } |
1028 | |
1029 | sub disconnect_call_do_sql { |
1030 | my $self = shift; |
1031 | $_->disconnect_call_do_sql(@_) for $self->all_storages; |
1032 | } |
1033 | |
1034 | sub _seems_connected { |
1035 | my $self = shift; |
1036 | |
1037 | return min map $_->_seems_connected, $self->all_storages; |
1038 | } |
1039 | |
1040 | sub _ping { |
1041 | my $self = shift; |
1042 | |
1043 | return min map $_->_ping, $self->all_storages; |
1044 | } |
1045 | |
bbdda281 |
1046 | # not using the normalized_version, because we want to preserve |
1047 | # version numbers much longer than the conventional xxx.yyyzzz |
7da56142 |
1048 | my $numify_ver = sub { |
1049 | my $ver = shift; |
1050 | my @numparts = split /\D+/, $ver; |
bbdda281 |
1051 | my $format = '%d.' . (join '', ('%06d') x (@numparts - 1)); |
7da56142 |
1052 | |
1053 | return sprintf $format, @numparts; |
1054 | }; |
fecb38cb |
1055 | sub _server_info { |
1056 | my $self = shift; |
1057 | |
bbdda281 |
1058 | if (not $self->_dbh_details->{info}) { |
1059 | $self->_dbh_details->{info} = ( |
fd323bf1 |
1060 | reduce { $a->[0] < $b->[0] ? $a : $b } |
7da56142 |
1061 | map [ $numify_ver->($_->{dbms_version}), $_ ], |
1062 | map $_->_server_info, $self->all_storages |
1063 | )->[1]; |
fecb38cb |
1064 | } |
1065 | |
bbdda281 |
1066 | return $self->next::method; |
fecb38cb |
1067 | } |
1068 | |
1069 | sub _get_server_version { |
1070 | my $self = shift; |
1071 | |
1072 | return $self->_server_info->{dbms_version}; |
1073 | } |
1074 | |
7e38d850 |
1075 | =head1 GOTCHAS |
1076 | |
1077 | Due to the fact that replicants can lag behind a master, you must take care to |
1078 | make sure you use one of the methods to force read queries to a master should |
1079 | you need realtime data integrity. For example, if you insert a row, and then |
1080 | immediately re-read it from the database (say, by doing $row->discard_changes) |
1081 | or you insert a row and then immediately build a query that expects that row |
1082 | to be an item, you should force the master to handle reads. Otherwise, due to |
1083 | the lag, there is no certainty your data will be in the expected state. |
1084 | |
1085 | For data integrity, all transactions automatically use the master storage for |
1086 | all read and write queries. Using a transaction is the preferred and recommended |
1087 | method to force the master to handle all read queries. |
1088 | |
1089 | Otherwise, you can force a single query to use the master with the 'force_pool' |
1090 | attribute: |
1091 | |
1092 | my $row = $resultset->search(undef, {force_pool=>'master'})->find($pk); |
1093 | |
1094 | This attribute will safely be ignore by non replicated storages, so you can use |
1095 | the same code for both types of systems. |
1096 | |
1097 | Lastly, you can use the L</execute_reliably> method, which works very much like |
1098 | a transaction. |
1099 | |
1100 | For debugging, you can turn replication on/off with the methods L</set_reliable_storage> |
1101 | and L</set_balanced_storage>, however this operates at a global level and is not |
1102 | suitable if you have a shared Schema object being used by multiple processes, |
1103 | such as on a web application server. You can get around this limitation by |
1104 | using the Schema clone method. |
1105 | |
1106 | my $new_schema = $schema->clone; |
1107 | $new_schema->set_reliable_storage; |
d4daee7b |
1108 | |
7e38d850 |
1109 | ## $new_schema will use only the Master storage for all reads/writes while |
1110 | ## the $schema object will use replicated storage. |
1111 | |
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1112 | =head1 AUTHOR |
1113 | |
64cdad22 |
1114 | John Napiorkowski <john.napiorkowski@takkle.com> |
f5d3a5de |
1115 | |
c4d3fae2 |
1116 | Based on code originated by: |
f5d3a5de |
1117 | |
64cdad22 |
1118 | Norbert Csongrádi <bert@cpan.org> |
1119 | Peter Siklósi <einon@einon.hu> |
2156bbdd |
1120 | |
f5d3a5de |
1121 | =head1 LICENSE |
1122 | |
1123 | You may distribute this code under the same terms as Perl itself. |
1124 | |
1125 | =cut |
1126 | |
c354902c |
1127 | __PACKAGE__->meta->make_immutable; |
1128 | |
f5d3a5de |
1129 | 1; |