The prior article finished the discussion on hard parsing. This article will take a look at some of the explain plan content then wrap up with what to look for when you have poorly performing SQL. Up to now, we have been discussing how Oracle processes SQL, the hard and soft parse processes, and how […]
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The prior article in this series finished the discussion on hard parsing. This article will take a look at the explain plan and discuss the order of processing and what the steps actually mean. Please be sure to read these articles in the proper order as they each build on the prior article! Let’s review […]
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The prior article started a discussion on the hard parsing process. It left off with the query transformation step. Please read these articles in the proper order as they each build on the prior article. The next step in the hard parse process is the permutations, as shown in the Figure below, taken from the […]
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In a previous article, I discussed the PLAN_TABLE and its role in SQL tuning for Oracle. This article will discuss using this PLAN_TABLE to display SQL execution plans, or explain plans. Technically, the Oracle Hard Parse process produces an execution plan. The explain plan is the visualization of this execution plan. I use the terms synonymously. […]
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How many times you have heard this question: “Why is SQL Server consuming so much memory?” If you ask a DBA who knows the functionality of SQL Server, the answer would be, “That is an expected behavior! Limit max server memory of SQL Server if you are concerned.” One might then wonder why SQL Server doesn’t release […]
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SQL Server 2014 introduced the new database engine enhancement called In-Memory OLTP. This feature uses new data structures which are optimized for in-memory access of table. People normally call it In-Memory database. In reality, we would like to call it partially in-memory database because SQL Server allows us to have few hot tables in-memory and […]
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If you’re database professional, you continuously face the challenge of improving database performance. Throwing hardware at the problem is a common solution to slow performance. And this approach often focuses on procuring SSD storage, servers, or CPU. But is ‘throwing hardware at the problem’ the right solution or is it just a big gamble? We […]
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This article will discuss the importance of the PLAN_TABLE and how to make sure you are using the correct one. The PLAN_TABLE, shown below, is used to produce SQL Explain Plans. When SQL is submitted to Oracle and processed (details to follow in other articles), an execution plan is created and used to process the […]
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The inventor of the relational model, Dr. Edgar Codd, was of the opinion that “[r]equesting data by its properties is far more natural than devising a particular algorithm or sequence of operations for its retrieval. Thus, a calculus-oriented language provides a good target language for a more user-oriented source language” (“Relational Completeness of Data Base […]
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Performance troubleshooting is one of the unique challenges every developer and DBA has to face. One of the major complaints about performance troubleshooting is utilization of resources. Few organizations resort to putting muscle power to scale up the system without analyzing the root cause of the performance problem. For example, a typical scenario might involve a SQL Server instance with memory […]
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Recently, I heard a story that was quite compelling. A retired naval officer used to get to the top of a bridge and keep waving his hand everyday around 8 PM. The passer-by used to think the elderly man had gone nuts and, after awhile, ignored his actions. One fine day, a stranger saw this and was […]
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Lately, the big IT buzzword is cloud solutions. In fact, if you believe all of the hype, most companies are moving en masse from on-premise solutions to cloud-based architectures. On the surface, the cloud-based solution certainly seems to be a more affordable solution that not only reduces the complexities of on-premise build-outs and maintenance, but […]
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