In this video, discover how to use explain and analyze commands.
- Now, I'm starting where I left off … in the last video. … You'll notice, I have some create table statements, … and insert commands, in my query window. … So, I'm going to leave those, … and I'm just going to create another query window, … so I'll have a clear window to start with. … Now, one of the first steps, … in optimizing queries, … is understanding how they're executing. … Remember, SEQUEL is declarative. … So, for example, … here is a simple declarative query. … We'll type "SELECT * FROM staff". … Now a query is a declarative statement … that must be mapped into … a procedural execution plan. … So we want to understand what that plan looks like, … and from there we can do a variety of things … to our data model, and query to try … and make it more efficient. … So let's just take a look at the results … of this select statement. … We'll notice here that there are … a thousand rows that are returned, … and if we take a look here … we can see the nine columns, … that we saw on the previous video, …
Author
Released
4/1/2019- How SQL executes queries
- Working with PostgreSQL tools for tuning
- Bitmap and hash indexes
- Using different types of indexes to improve performance
- Challenges with joining tables
- When to use partitioning to improve performance
- Collecting statistics about data in tables
Skill Level Advanced
Duration
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Introduction
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1. How SQL Executes a Query
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Scanning tables and indexes3m 12s
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Joining tables2m 24s
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Partitioning data2m 23s
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2. PostgreSQL Tools for Tuning
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Installing PostgreSQL2m 41s
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Overview of pgAdmin3m 21s
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Explain and analyze3m 37s
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Indexes3m 7s
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3. Types of Indexes
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Indexing3m 1s
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B-tree indexes2m 2s
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B-tree index example plan2m 18s
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Bitmap indexes1m 46s
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Bitmap index example plan2m 39s
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Hash indexes1m 19s
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Hash index example plan1m 32s
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PostgreSQL-specific indexes1m 17s
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4. Tuning Joins
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Nested loops3m 19s
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Nested loop example plan3m 55s
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Hash joins1m 25s
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Hash join example plan1m 57s
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Merge joins2m 17s
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Merge join example3m 16s
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Subqueries vs. joins1m 11s
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5. Partitioning Data
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Partition by range2m 6s
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Partition by list1m 37s
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Partition by list example4m 55s
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Partition by hash2m 12s
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Partition by hash example4m 51s
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6. Materialized Views
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Materialized views1m 41s
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7. Other Optimization Techniques
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Hints to the query optimizer2m 13s
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Parallel query execution2m 3s
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Miscellaneous tips1m 47s
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Conclusion
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Next steps41s
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Video: Explain and analyze