PostgreSQL Database Administration Quiz Questions and Answers
Answer :
A transaction that re-executes a query, returning a set of rows that satisfy a search condition and then finds that the set of rows that have been satisfying the condition has changed due to another recently-committed transaction.
Explanation :
A transaction that re-executes a query, returning a set of rows that satisfy a search condition and then finds that the set of rows that have been satisfying the condition has changed due to another recently-committed transaction.
A transaction that re-reads the data that it has previously read and then finds that data has already been modified by another transaction (that committed since the initial read).
Explanation :
A transaction that re-reads the data that it has previously read and then finds that data has already been modified by another transaction (that committed since the initial read)