What happens when a SELECT query is blocked?
As soon as the select query completes, it will release locks and the insert will complete. A timeout due to blocking (or poorly performing query) may occur if the client CommandTimeout property is set to a value other than zero (30 seconds is the default with most APIs).
Can you select rows that are not present in another table?
Select rows which are not present in other table. You can use a Unique Index for preventing duplicated rows. But if you want to insert rows filtering it to not insert duplicated rows, you can do this. Create a unique index on that column and be done with it. No need to check.
When to insert a row into a table?
For each individual row proposed for insertion, either the insertion proceeds, or, if an arbiter constraint or index specified by conflict_target is violated, the alternative conflict_action is taken. ON CONFLICT DO NOTHING simply avoids inserting a row as its alternative action. Bold emphasis mine.
How does SELECT query work in Stack Overflow?
That means that your SELECT queries will block UPDATE and INSERT queries and vice versa. A SELECT query will place a temporary shared lock when it reads a block of values from the table, and remove it when it done reading. For the time the lock exists, you will not be able to do anything with the data in the locked area.
Is it possible to execute SELECT statement in SQL Server?
For versions below 12c, the plain answer is NO, at least not in the manner it is being done is SQL Server. but you cannot execute SELECT statement, without doing something with the results. You need to use Native dynamic SQL.
When to use shared lock in SELECT query?
A SELECT query will place a temporary shared lock when it reads a block of values from the table, and remove it when it done reading. For the time the lock exists, you will not be able to do anything with the data in the locked area.