In this video, see a hash index in a query plan.
- [Instructor] Okay, let's see how to create a hash index. … I'm going to use the email column of the staff table … as my example. … Now, the email column is a good candidate … since the email should be unique to each person, … and it's likely we want to be able … to look up a person's staff data by their email. … Also, it's not likely that we'd want to perform … a range query on the email addresses. … So let's create a hash index. … We use the create index command, and we give it a name, … we specify the term ON followed by the table name. … Now, instead of just specifying the column name here, … I'm going to specify USING HASH and then … specify the column name. … And let's execute that. … So we've created a hash index. … Now let's see if it actually gets used. … And to do that, we're going to use as our example … SELECT * FROM staff WHERE email is equal to … and we'll use bphillips and let's just execute that, … make sure I got it correct. … Bphillips, oh excuse me, it's bphillips5 I believe. …
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
Views
Related Courses
-
Advanced SQL for Data Scientists
with Dan Sullivan1h 24m Advanced -
Introduction to Spark SQL and DataFrames
with Dan Sullivan1h 53m Intermediate
-
Introduction
-
1. How SQL Executes a Query
-
Scanning tables and indexes3m 12s
-
Joining tables2m 24s
-
Partitioning data2m 23s
-
2. PostgreSQL Tools for Tuning
-
Installing PostgreSQL2m 41s
-
Overview of pgAdmin3m 21s
-
Explain and analyze3m 37s
-
Indexes3m 7s
-
-
3. Types of Indexes
-
Indexing3m 1s
-
B-tree indexes2m 2s
-
B-tree index example plan2m 18s
-
Bitmap indexes1m 46s
-
Bitmap index example plan2m 39s
-
Hash indexes1m 19s
-
Hash index example plan1m 32s
-
PostgreSQL-specific indexes1m 17s
-
-
4. Tuning Joins
-
Nested loops3m 19s
-
Nested loop example plan3m 55s
-
Hash joins1m 25s
-
Hash join example plan1m 57s
-
Merge joins2m 17s
-
Merge join example3m 16s
-
Subqueries vs. joins1m 11s
-
5. Partitioning Data
-
Partition by range2m 6s
-
Partition by list1m 37s
-
Partition by list example4m 55s
-
Partition by hash2m 12s
-
Partition by hash example4m 51s
-
6. Materialized Views
-
Materialized views1m 41s
-
-
7. Other Optimization Techniques
-
Hints to the query optimizer2m 13s
-
Parallel query execution2m 3s
-
Miscellaneous tips1m 47s
-
Conclusion
-
Next steps41s
-
- Mark as unwatched
- Mark all as unwatched
Are you sure you want to mark all the videos in this course as unwatched?
This will not affect your course history, your reports, or your certificates of completion for this course.
CancelTake notes with your new membership!
Type in the entry box, then click Enter to save your note.
1:30Press on any video thumbnail to jump immediately to the timecode shown.
Notes are saved with you account but can also be exported as plain text, MS Word, PDF, Google Doc, or Evernote.
Share this video
Embed this video
Video: Hash index example plan