| --- |
| layout: doc_page |
| --- |
| Broker Node Configuration |
| ========================= |
| For general Broker Node information, see [here](Broker.html). |
| |
| Runtime Configuration |
| --------------------- |
| |
| The broker module uses several of the default modules in [Configuration](Configuration.html) and has the following set of configurations as well: |
| |
| |Property|Possible Values|Description|Default| |
| |--------|---------------|-----------|-------| |
| |`druid.broker.cache.type`|`local`, `memcached`|The type of cache to use for queries.|`local`| |
| |`druid.broker.balancer.type`|`random`, `connectionCount`|Determines how the broker balances connections to historical nodes. `random` choose randomly, `connectionCount` picks the node with the fewest number of active connections to|`random`| |
| |
| #### Local Cache |
| |
| |Property|Description|Default| |
| |--------|-----------|-------| |
| |`druid.broker.cache.sizeInBytes`|Maximum cache size in bytes. Zero disables caching.|0| |
| |`druid.broker.cache.initialSize`|Initial size of the hashtable backing the cache.|500000| |
| |`druid.broker.cache.logEvictionCount`|If non-zero, log cache eviction every `logEvictionCount` items.|0| |
| |
| #### Memcache |
| |
| |Property|Description|Default| |
| |--------|-----------|-------| |
| |`druid.broker.cache.expiration`|Memcached [expiration time](https://code.google.com/p/memcached/wiki/NewCommands#Standard_Protocol).|2592000 (30 days)| |
| |`druid.broker.cache.timeout`|Maximum time in milliseconds to wait for a response from Memcached.|500| |
| |`druid.broker.cache.hosts`|Command separated list of Memcached hosts `<host:port>`.|none| |
| |`druid.broker.cache.maxObjectSize`|Maximum object size in bytes for a Memcached object.|52428800 (50 MB)| |
| |`druid.broker.cache.memcachedPrefix`|Key prefix for all keys in Memcached.|druid| |
