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query cancellation/timeout docs + missing items

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Xavier Léauté 2014-08-01 09:47:12 -07:00
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docs/content/Querying.md
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@ -108,21 +108,52 @@ Query Operators
The following table summarizes query properties.
|query types|property|description|required?|
|-----------|--------|-----------|---------|
|timeseries, groupBy, search, timeBoundary|dataSource|query is applied to this data source|yes|
|timeseries, groupBy, search|intervals|range of time series to include in query|yes|
|timeseries, groupBy, search, timeBoundary|context|This is a key-value map that can allow the query to alter some of the behavior of a query. It is primarily used for debugging, for example if you include `"bySegment":true` in the map, you will get results associated with the data segment they came from.|no|
|timeseries, groupBy, search|filter|Specifies the filter (the "WHERE" clause in SQL) for the query. See [Filters](Filters.html)|no|
|timeseries, groupBy, search|granularity|the timestamp granularity to bucket results into (i.e. "hour"). See [Granularities](Granularities.html) for more information.|no|
Properties shared by all query types
|property |description|required?|
|----------|-----------|---------|
|dataSource|query is applied to this data source|yes|
|intervals |range of time series to include in query|yes|
|context |This is a key-value map used to alter some of the behavior of a query. See [Query Context](#query-context) below|no|
|query type|property |description|required?|
|----------|----------|-----------|---------|
|timeseries, topN, groupBy, search|filter|Specifies the filter (the "WHERE" clause in SQL) for the query. See [Filters](Filters.html)|no|
|timeseries, topN, groupBy, search|granularity|the timestamp granularity to bucket results into (i.e. "hour"). See [Granularities](Granularities.html) for more information.|no|
|timeseries, topN, groupBy|aggregations|aggregations that combine values in a bucket. See [Aggregations](Aggregations.html).|yes|
|timeseries, topN, groupBy|postAggregations|aggregations of aggregations. See [Post Aggregations](Post Aggregations.html).|yes|
|groupBy|dimensions|constrains the groupings; if empty, then one value per time granularity bucket|yes|
|timeseries, groupBy|aggregations|aggregations that combine values in a bucket. See [Aggregations](Aggregations.html).|yes|
|timeseries, groupBy|postAggregations|aggregations of aggregations. See [Post Aggregations](Post Aggregations.html).|yes|
|search|limit|maximum number of results (default is 1000), a system-level maximum can also be set via `com.metamx.query.search.maxSearchLimit`|no|
|search|searchDimensions|Dimensions to apply the search query to. If not specified, it will search through all dimensions.|no|
|search|query|The query portion of the search query. This is essentially a predicate that specifies if something matches.|yes|
Additional Information about Query Types
----------------------------------------
Query Context
-------------
[TimeseriesQuery](TimeseriesQuery.html)
|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 overriden 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. Pimarily 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` |
Query Cancellation
------------------
Queries can be cancelled explicitely using their unique identifier. If the
query identifier is set at the time of query, or is known, the following
endpoint can be used on the broker or router to cancel the query.
```sh
DELETE /druid/v2/{queryId}
```
For example, if the query ID is `abc123`, the query can be cancelled as follows:
```sh
curl -X DELETE "http://host:port/druid/v2/abc123"
```