For general Broker Node information, see here.
The broker module uses several of the default modules in Configuration and has the following set of configurations as well:
| Property | Possible Values | Description | Default |
|---|---|---|---|
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 |
druid.broker.select.tier | highestPriority, lowestPriority, custom | If segments are cross-replicated across tiers in a cluster, you can tell the broker to prefer to select segments in a tier with a certain priority. | highestPriority |
druid.broker.select.tier.custom.priorities | An array of integer priorities. | Select servers in tiers with a custom priority list. | None |
druid.broker.cache.type | local, memcached | The type of cache to use for queries. | local |
druid.broker.cache.unCacheable | All druid query types | All query types to not cache. | [“groupBy”, “select”] |
| 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 |
| Property | Description | Default |
|---|---|---|
druid.broker.cache.expiration | Memcached expiration time. | 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 |