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PostgreSQL 10 High Performance

You're reading from   PostgreSQL 10 High Performance Expert techniques for query optimization, high availability, and efficient database maintenance

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Product type Paperback
Published in Apr 2018
Publisher Packt
ISBN-13 9781788474481
Length 508 pages
Edition 3rd Edition
Languages
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Author (1):
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Enrico Pirozzi Enrico Pirozzi
Author Profile Icon Enrico Pirozzi
Enrico Pirozzi
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Table of Contents (18) Chapters Close

Preface 1. PostgreSQL Versions FREE CHAPTER 2. Database Hardware 3. Database Hardware Benchmarking 4. Disk Setup 5. Memory for Database Caching 6. Server Configuration Tuning 7. Routine Maintenance 8. Database Benchmarking 9. Database Indexing 10. Query Optimization 11. Database Activity and Statistics 12. Monitoring and Trending 13. Pooling and Caching 14. Scaling with Replication 15. Partitioning Data 16. Avoiding Common Problems 17. Other Books You May Enjoy

Sources of bad results and variation

There are many ways to get bad results from pgbench, ones that don't mean anything valid. And there are even more ways to get results that vary so much from one pgbench run to another that they don't mean what you would imagine them to. Normally you should run any pgbench test at least three times and observe the average and variation before presuming that test is valid. Taking the middle of three results is a common median technique for filtering those results into a single one for comparison.

You must let the test run for a while to get useful results. As a general rule of thumb, if you haven't executed a minute's worth of runtime, you're unlikely to have gotten useful results at all. The main exception is the SELECT only test, which can give useful results in a small number of seconds. Generally, if you've seen...

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