1DBIx::Class::Storage::DUBsIe:r:RCeoDpnBltIirxci:ab:tuCetldea:ds:sBP:ae:lrSaltnocDreoarcg(ue3m:)e:nDtBaIt:i:oRneplicated::Balancer(3)
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6 DBIx::Class::Storage::DBI::Replicated::Balancer - A Software Load
7 Balancer
8
10 This role is used internally by DBIx::Class::Storage::DBI::Replicated.
11
13 Given a pool (DBIx::Class::Storage::DBI::Replicated::Pool) of
14 replicated database's
15 (DBIx::Class::Storage::DBI::Replicated::Replicant), defines a method by
16 which query load can be spread out across each replicant in the pool.
17
19 This class defines the following attributes.
20 auto_validate_every ($seconds)
22 If auto_validate has some sort of value, run "validate_replicants" in
23 DBIx::Class::Storage::DBI::Replicated::Pool every $seconds. Be careful
24 with this, because if you set it to 0 you will end up validating every
25 query.
26 master
28 The DBIx::Class::Storage::DBI object that is the master database all
29 the replicants are trying to follow. The balancer needs to know it
30 since it's the ultimate fallback.
31 pool
33 The DBIx::Class::Storage::DBI::Replicated::Pool object that we are
34 trying to balance.
35 current_replicant
37 Replicant storages (slaves) handle all read only traffic. The
38 assumption is that your database will become readbound well before it
39 becomes write bound and that being able to spread your read only
40 traffic around to multiple databases is going to help you to scale
41 traffic.
42 This attribute returns the next slave to handle a read request. Your
44 "pool" attribute has methods to help you shuffle through all the
45 available replicants via its balancer object.
46
48 This class defines the following methods.
49 _build_current_replicant
51 Lazy builder for the "current_replicant" attribute.
52 next_storage
54 This method should be defined in the class which consumes this role.
55 Given a pool object, return the next replicant that will serve queries.
57 The default behavior is to grab the first replicant it finds but you
58 can write your own subclasses of
59 DBIx::Class::Storage::DBI::Replicated::Balancer to support other
60 balance systems.
61 This returns from the pool of active replicants. If there are no
63 active replicants, then you should have it return the master as an
64 ultimate fallback.
65 around: next_storage
67 Advice on next storage to add the autovalidation. We have this broken
68 out so that it's easier to break out the auto validation into a role.
69 This also returns the master in the case that none of the replicants
71 are active or just forgot to create them :)
72 increment_storage
74 Rolls the Storage to whatever is next in the queue, as defined by the
75 Balancer.
76 around: select
78 Advice on the select attribute. Each time we use a replicant we need
79 to change it via the storage pool algorithm. That way we are spreading
80 the load evenly (hopefully) across existing capacity.
81 around: select_single
83 Advice on the select_single attribute. Each time we use a replicant we
84 need to change it via the storage pool algorithm. That way we are
85 spreading the load evenly (hopefully) across existing capacity.
86 before: columns_info_for
88 Advice on the current_replicant_storage attribute. Each time we use a
89 replicant we need to change it via the storage pool algorithm. That
90 way we are spreading the load evenly (hopefully) across existing
91 capacity.
92 _get_forced_pool ($name)
94 Given an identifier, find the most correct storage object to handle the
95 query.
96
98 Check the list of additional DBIC resources.
99
101 This module is free software copyright by the DBIx::Class (DBIC)
102 authors. You can redistribute it and/or modify it under the same terms
103 as the DBIx::Class library.
104perl v5.32.1 DBIx::2C0l2a1s-s0:1:-S2t7orage::DBI::Replicated::Balancer(3)