druid/docs/content/querying/query-context.md

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Query Context

The query context is used for various query configuration parameters.

property default description
timeout 0 (no timeout) Query timeout in milliseconds, beyond which unfinished queries will be cancelled.
priority 0 Query Priority. Queries with higher priority get precedence for computational resources.
queryId auto-generated Unique identifier given to this query. If a query ID is set or known, this can be used to cancel the query
useCache true Flag indicating whether to leverage the query cache for this query. This may be overridden in the broker or historical node configuration
populateCache true Flag indicating whether to save the results of the query to the query cache. Primarily used for debugging. This may be overriden in the broker or historical node configuration
bySegment false Return "by segment" results. Primarily used for debugging, setting it to true returns results associated with the data segment they came from
finalize true Flag indicating whether to "finalize" aggregation results. Primarily used for debugging. For instance, the hyperUnique aggregator will return the full HyperLogLog sketch instead of the estimated cardinality when this flag is set to false
chunkPeriod 0 (off) At the broker node level, long interval queries (of any type) may be broken into shorter interval queries, reducing the impact on resources. Use ISO 8601 periods. For example, if this property is set to P1M (one month), then a query covering a year would be broken into 12 smaller queries. All the query chunks will be processed asynchronously inside query processing executor service. Make sure "druid.processing.numThreads" is configured appropriately on the broker.
minTopNThreshold 1000 The top minTopNThreshold local results from each segment are returned for merging to determine the global topN.
maxResults 500000 Maximum number of results groupBy query can process. Default value used can be changed by druid.query.groupBy.maxResults in druid configuration at broker and historical nodes. At query time you can only lower the value.
maxIntermediateRows 50000 Maximum number of intermediate rows while processing single segment for groupBy query. Default value used can be changed by druid.query.groupBy.maxIntermediateRows in druid configuration at broker and historical nodes. At query time you can only lower the value.
groupByIsSingleThreaded false Whether to run single threaded group By queries. Default value used can be changed by druid.query.groupBy.singleThreaded in druid configuration at historical nodes.