Articles tagged

09 February 2017
09 February 2017

Oracle Partitioned Index Efficiency

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PartitionedIndexEfficiency Although it is generally true that rebuilding an index represents a waste of time and resources, there nevertheless exist situations where degenerated indexes might benefit from reorganisation. When you think you are in such a situation, instead of shooting in the dark and rebuilding all indexes, you are better off finding and rebuilding only those indexes occupying more spac… Read more
03 February 2017
03 February 2017

Understanding SQL Query Parsing: Part 4 – Understanding Bind Variable Peeking

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In the 3rd part of this series, I introduced you to the concept of the bind variables. We also learned their importance in regard to cursors, i.e. how with the presence of bind variables, cursor reparsing can be reduced significantly. But as is famously said in the world of performance tuning, there is nothing black or white: it’s all grey… Read more
09 January 2017
09 January 2017

Investigating Indexes – 2

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In an earlier article on investigating indexes I described some methods for looking at the internal structure of an index to get an idea of its current state of health. Although this type of knowledge helps you to make informed decisions about which indexes might need special treatment (like being permanently dropped, perhaps) it doesn’t immediately answer questions like: “what’s… Read more
16 June 2016
16 June 2016

Defragmentation Can Degrade Query Performance

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As data in tables is updated and / or deleted, pockets of empty space can be created, leading to fragmented free space. This free space is wasted space as it is insufficient to hold new data. Moreover, it can impact performance of the database as a higher number of sparsely-populated blocks need to be visited. Oracle 11g introduced online segment… Read more
and 10 September 2014
and 10 September 2014

SQL Server Performance Troubleshooting with SQL Monitor 5

Any SQL Server monitoring tool must gather the metrics that will allow a DBA to diagnose CPU, memory or I/O issues on their SQL Servers. It should also provide a set of accurate, reliable, configurable alerts that will inform the DBA of any abnormal or undesirable conditions and properties, as well as specific errors, on any of the monitored servers. This article provides an in-depth guide to the monitoring and alerting functionality available in one such tool, Redgate SQL Monitor. It focuses on the latest edition (5.0), which includes several key new features, such as performance diagnosis using wait statistics, the ability to compare to baselines, and more.… Read more