Oracle Magazine, March/April 2019
Database Developer and DBA ETL straight into utilizing these tuning tools without stepping back and asking a few key questions about the SQL statement first What is the business functional requirement being served by the SQL Is the SQL correct Can this SQL ever run fast enough to meet the requirements Even without diving into low level tools it is easy to forget these questions I frequently visit clients to assist with performance tuning issues and upon my arrival often the first thing presented to me is a single SQL statement with no context or explanation surrounding it and this plea This is the problem Please solve it It may seem counterintuitive but the first step of SQL tuning is to forget about the SQL THE BUSINESS REQUIREMENT No organization Im aware of has ever had a business model of Lets make sure SQL runs fast unless that business was a SQL tuning consultancy SQL statements the applications that run them and the IT departments that build and support those applications exist to meet a suite of business functional requirements Those requirements may be created by the business as part of its desire to thrive commercially or they may be imposed on the business by regulatory bodies In either case satisfying business requirements must be kept uppermost in a developers mindset when it comes to tuning SQL because it drives the very decisions made by developers in creating the database design and the SQL that runs on it Ignoring the underlying business requirements is a catalyst for poorly performing SQL Ill demonstrate that with a real example of my experience with a client that requested some SQL tuning assistance For the sake of anonymity the descriptions and the SQL code are obfuscated but other than that this is a reasonably accurate ORACLE MAGAZINE MARCH APRIL 2019 100
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