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How do I create a query selective in Salesforce?
Example:
- Get the SOQL query and replace the list of fields with the count() operator:
- Check the number of active records in the table:
- The only filter in the WHERE clause with an index is CreatedDate, so we will only consider the filter on this field.
- Let’s check though if the filter on Status__c is selective:
What is indexing in Salesforce?
In the modern cloud application with a large data set like Salesforce, indexing is very important to allow an application to search and return results to users at a minimum time and cost. Indexing will also be used by query optimizer to gather the statistics of each index.
How is query optimization done in SQL Server?
Query optimization in SQL Server is backed up by in-built tools. SQL Server Profiler is a tool bundled with MS SQL Server package. It helps us to trace queries received by the server. This allows us to see the text of the query and check the execution time.
How is execution plan used to optimize SQL?
Execution plan also can show you missing indexes that could improve performance and thus optimize SQL query. It would look like this: Apart from showing the index that needs to be added, plan also shows what kind of effect we will get from it. In this case, it will increase performance on 38%.
Why are some SQL queries slower than others?
Hence, developers get a quick response to the queries they write. But the problem starts when the project goes live and enormous data starts flooding the database. Such instances slow down SQL queries response drastically and create performance issues.
How are statistics used in a query optimizer?
Statistics are an important part of the entire process as they help the query optimizer to make the best guesses when accessing data. These statistics include information about columns like: estimated number of rows, the density of pages on disk, available indexes to use, etc. that the query optimizer uses to generate query plans.