consul/.changelog/12110.txt

```release-note:improvement
rpc: improve blocking queries for items that do not exist, by continuing to block until they exist (or the timeout).
```
Make blockingQuery efficient with 'not found' results. By using the query results as state. Blocking queries are efficient when the query matches some results, because the ModifyIndex of those results, returned as queryMeta.Mindex, will never change unless the items themselves change. Blocking queries for non-existent items are not efficient because the queryMeta.Index can (and often does) change when other entities are written. This commit reduces the churn of these queries by using a different comparison for "has changed". Instead of using the modified index, we use the existence of the results. If the previous result was "not found" and the new result is still "not found", we know we can ignore the modified index and continue to block. This is done by setting the minQueryIndex to the returned queryMeta.Index, which prevents the query from returning before a state change is observed. 2022-01-13 00:44:09 +00:00			```release-note:improvement
			`rpc: improve blocking queries for items that do not exist, by continuing to block until they exist (or the timeout).`
			```