Query consistency policy
Applies to: ✅ Microsoft Fabric ✅ Azure Data Explorer
A workload group's query consistency policy allows specifying options that control the consistency mode of queries.
The policy object
Each option consists of:
- A typed
Value
- the value of the limit. IsRelaxable
- a boolean value that defines if the option can be relaxed by the caller, as part of the request's request properties. Default istrue
.
The following limits are configurable:
Name | Type | Description | Supported values | Default value | Matching client request property |
---|---|---|---|---|---|
QueryConsistency | QueryConsistency |
The consistency mode to use. | Strong , Weak , or WeakAffinitizedByQuery , WeakAffinitizedByDatabase |
Strong |
queryconsistency |
CachedResultsMaxAge | timespan |
The maximum age of cached query results that can be returned. | A non-negative timespan |
null |
query_results_cache_max_age |
Note
The default value applies in the following cases:
- The policy isn't defined, and the client request option isn't set.
- The policy is defined, the option isn't defined, and the client request option isn't set.
- The policy is defined, the option is defined with
null
as itsValue
, and the client request option isn't set.
Example
"QueryConsistencyPolicy": {
"QueryConsistency": {
"IsRelaxable": true,
"Value": "Weak"
},
"CachedResultsMaxAge": {
"IsRelaxable": true,
"Value": "05:00:00"
}
}
Monitoring
You can monitor the latency of the metadata snapshot age on nodes serving as weak consistency service heads by using the Weak consistency latency
metric. For more information, see Query metrics.