| description |
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Configure offline message store. |
In the vanilla VerneMQ(1.11.0) on netsplit, the broker state had to be cleared before restoration which led to loss of offline messages stored in leveldb using vmq_generic_message_store plugin. Since this kind of persistence is actually not useful so no-op engine was introduced which bypass this persistence step and helped in quick recovery of broker as there was no message state to be loaded in memory.
Using offline message store, only offline messages are persisted for the offline clients. In order to use offline message store, message store plugin needs to be explicitly configured.
message_store_plugin = vmq_generic_offline_msg_store
Currently two offline store engines are available, postgres and redis sentinel.
Specify the engine to be used for storage.
offline_message_store_engine = vmq_offline_storage_engine_redis
For redis sentinel engine, all the hosts(master and slaves) can be specified in a list format, ["host1", "host2"]
offline_message_store_opts.host = localhost
Specify the port on which the offline store is listening.
offline_message_store_opts.port = 6379
Specify the name of the database to be used as offline store.
offline_message_store_opts.database = 2
Specify the connect timeout (in milliseconds).
offline_message_store_opts.connect_timeout = 4000
Specify the query timeout (in milliseconds).
offline_message_store_opts.query_timeout = 2000