Module Sequel::Postgres::StaticCacheUpdater
In: lib/sequel/extensions/pg_static_cache_updater.rb

Methods

Public Instance methods

Add the static cache update function to the PostgreSQL database. This must be added before any triggers using this function are added.

Options:

:channel_name :Override the channel name to use.
:function_name :Override the function name to use.

[Source]

    # File lib/sequel/extensions/pg_static_cache_updater.rb, line 80
80:       def create_static_cache_update_function(opts=OPTS)
81:         create_function(opts[:function_name]||default_static_cache_update_name, "BEGIN\n  PERFORM pg_notify(\#{literal((opts[:channel_name]||default_static_cache_update_name).to_s)}, TG_RELID::text);\n  RETURN NULL;\nEND\n", :returns=>:trigger, :language=>:plpgsql)
82:       end

Add a trigger to the given table that calls the function which will notify about table changes.

Options:

:function_name :Override the function name to use.
:trigger_name :Override the trigger name to use.

[Source]

    # File lib/sequel/extensions/pg_static_cache_updater.rb, line 96
96:       def create_static_cache_update_trigger(table, opts=OPTS)
97:         create_trigger(table, opts[:trigger_name]||default_static_cache_update_name, opts[:function_name]||default_static_cache_update_name, :after=>true)
98:       end

The default name for the function, trigger, and notification channel for this extension.

[Source]

     # File lib/sequel/extensions/pg_static_cache_updater.rb, line 102
102:       def default_static_cache_update_name
103:         :sequel_static_cache_update
104:       end

Listen on the notification channel for changes to any of tables for the models given in a new thread. If notified about a change to one of the tables, reload the cache for the related model. Options given are also passed to Database#listen.

Note that this implementation does not currently support multiple models that use the same underlying table.

Options:

:channel_name :Override the channel name to use.
:before_thread_exit :An object that responds to call that is called before the the created thread exits.

[Source]

     # File lib/sequel/extensions/pg_static_cache_updater.rb, line 118
118:       def listen_for_static_cache_updates(models, opts=OPTS)
119:         raise Error, "this database object does not respond to listen, use the postgres adapter with the pg driver" unless respond_to?(:listen)
120:         models = [models] unless models.is_a?(Array)
121:         raise Error, "array of models to listen for changes cannot be empty" if models.empty?
122: 
123:         oid_map = {}
124:         models.each do |model|
125:           raise Error, "#{model.inspect} does not use the static_cache plugin" unless model.respond_to?(:load_cache, true)
126:           oid_map[get(regclass_oid(model.dataset.first_source_table))] = model
127:         end
128: 
129:         Thread.new do
130:           begin
131:             listen(opts[:channel_name]||default_static_cache_update_name, {:loop=>true}.merge!(opts)) do |_, _, oid|
132:               if model = oid_map[oid.to_i]
133:                 model.send(:load_cache)
134:               end
135:             end
136:           ensure
137:             opts[:before_thread_exit].call if opts[:before_thread_exit]
138:           end
139:         end
140:       end

[Validate]