如果你说的是set的cardinality，那么cardinality就是集合中元素的个数。那么，你可能会问：直接叫count不...
Cardinality estimation (CE) in SQL Server is derived primarily from histograms that are created when indexes or statistics are created, either manually or automatically. Sometimes, SQL Server also uses constraint information and logical rewrites of queries to determine cardinality....
Subsequent updates started with SQL Server 2014 (12.x), meaning compatibility levels 120 and above. The CE updates for levels 120 and above incorporate updated assumptions and algorithms that work well on modern data warehousing and on OLTP workloads. From the CE 70 assumptions, the following ...
The bigger the table, the larger the data size - at a certain point, the saving in the dictionary no longer replaces the saving in data size. There is a point where the optimization is actually worsening the situation also in data size. It seems you are at the sweet point, mean...
Cardinality estimation (CE) in SQL Server is derived primarily from histograms that are created when indexes or statistics are created, either manually or automatically. Sometimes, SQL Server also uses constraint information and logical rewrites of queries to determine cardinality....
* This code executes registered procedures stored in the * operator relation, by calling the function manager. * * See clause_selectivity() for the meaning of the additional parameters. */Selectivityrestriction_selectivity(PlannerInfo *root,
Only after filtering for people living in, say, Quebec on one side and filtering for people who speak French on the other would you have a kind of implied relationship. (Many people who live in Quebec speak French). There is no inherent relationship of meaning between t...
“Overall, the introduction of InfluxDB 3.0 represents the beginning of a new chapter for the InfluxDB platform, giving users the ability to create time series on the fly from raw, high-precision data, meaning it powers expanded use cases across observability, real-...
Using the TreeLSTM model, we can better capture the meaning and relationships of join operations in SQL queries, allowing us to better handle complex query statements and Boolean operators (conjunction or disjunction) between predicates. Specifically, we model the “WHERE” clause of the query ...
/// Adds a tag to be included in any metric or Sentry error emitted from this point in the /// request lifecycle onwards. Tags **must** have low cardinality, meaning that the number of /// distinct possible values associated with a given tag must be small. fn add_tag(&self, key:...