SQL Databases

Top 10 Performance Tuning Mistakes of SQL Databases

in Technology on June 11, 2020

Several companies own SQL databases; however, not all can perform their databases to the optimal extent. Note, performance tuning engages the process of homogenizing the design of system files to the environment of the database. You must ensure that you assign the task to experts with experience and knowledge in the above to get the best results. In case your organization is not using performance tuning for the database, you could end up with a slow database. This will affect both the internal and external functions of the organizations. The end-user will be satisfied, and your business will suffer tremendously in terms of growth and customer satisfaction.

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How are SQL databases different from the rest?

If you carefully examine most of the programming languages popular today, you will find them specially designed for skilled developers with sound knowledge of data structure and algorithms. However, the SQL language is quite different. It is deployed by product managers, data scientists, designers, analysts, and others. All of these professionals have access to the database; however, they might not have an understanding of the intuition to create efficient SQL Queries. This is why if you have an SQL database in the organization, you must ensure that your IT team is well-versed with SQL queries so that performance tuning issues can be identified and corrected promptly.

How can you create better SQL queries?

Every developer has the goal to create better SQL; however, most of the time, they commit general mistakes. Given below are the general performance mistakes taken from code reviews that lead to missed opportunities in SQL optimization-

1. Management of bad connection – SQL Databases

Developers create the configuration code for connecting the database to the application or for running queries for fetching data from the system. After this data has been fetched and nothing else is needed, this code must close the connection to the system. However, this might not take place, resulting in an increased volume of inactive sessions. These inactive sessions in the system utilize valuable resources that could have been deployed for other connections in the database that are presently active.

2. Shared pool and cursors have been used badly

Developers generally have cursors in their arsenal kits that mostly remain utilized. Oracle faces typically a tough time when it comes to parsing a code each time it is run without a cursor. This mostly adversely impacts SQL query performance that runs repeatedly. An experienced and skilled DBA can recognize this issue by checking the AWR report section in the database.

3. Bad SQL

The performance of the SQL database depends upon the quality of its query. The way it is written will affect the performance of the system, and this also covers join conditions for fetching the data post-execution. For big tables, do not use a full table scan. After you have written the SQL, you should incorporate an explain plan for the SQL query to comprehend the costs of running it in the system. You should increase its efficiency with bind variables, indexes, and cursors.

4. Using sub-standard initialization parameters

DBAs should optimize the recommended parameters for initialization. The use of these parameters will enhance the performance of the database. Check the Oracle Service Request for suggestions in case you are not sure.

5. Wrong I/O database

A good DBA will choose the right hardware for the system so that it is easily distributed over several disks to boost speed. The professional should discuss the subject with the rest of the network team. The speed at which the data should travel in the system should be considered and discussed. The speed of the routers, as well as the network switches, should be taken into account so that performance mistakes and other bottlenecks in the system are averted.

6. Redo the log-setup issues

It is essential for you to redo the logs as they store data from the redo buffer for Oracle to redo transactions in the event of a server crash. If the size of the redo log is not sufficient, multiple switches will occur in the system leading to performance issues. This makes the load heavy for the archive generation to handle.

7. Buffer cache and serialization of data blocks

This takes place due to the deficiency of undo segments of free list sets. This scenario is typical for large databases with multiple active users having lesser undo segments that lead to many issues in performance.

8. Full table scans

Look out for full table scans in SQL queries. This can be done by running explain plans. Experienced DBAs from reliable database management and administration company in the USA, Remote.DBA.com states that queries that reflect bad SQL designs can be rectified with the use of indexes. This can be done by narrowing the data needed. In some cases, the full table scans are helpful for small tables.

9. Recursive SQL – SQL Databases

This can be a boon to database developers if they are used correctly; however, you must be careful. They are like a double-edged sword. If you can get them right, the efficiency of the database output increases, affecting the performance of the database positively.

10. In-disk sorting – SQL Databases

This is a very costly task for a database. It means the SQL design is poor and has been poorly optimized. The issue can be quickly identified in AWR reports that deal with activity statistics.

Therefore, in conclusion, it can be said that experienced and skilled DBAs should consider different arenas of performance tuning that begin with application and database design. Databases, as well as apps created with the goal of performance tuning, are better when it comes to scalability and functionality.

Every professional dealing with performance tuning in the SQL should keep themselves informed and updated with the latest technologies. Besides, the 10 issues listed here, it is prudent to be aware so that other mistakes can be rectified quickly without hampering the performance of the SQL database to boost speed and functionality to its best possible limits.

Author Bio:

Karen is a Business Tech Analyst. She loves to share her knowledge with friends.

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