Amazon-DEA-C01 Exam - Topic 4 Question 5 Discussion

Actual exam question for Amazon's Amazon-DEA-C01 exam

Question #: 5
Topic #: 4

A data engineer maintains a materialized view that is based on an Amazon Redshift database. The view has a column named load_date that stores the date when each row was loaded.

The data engineer needs to reclaim database storage space by deleting all the rows from the materialized view.

Which command will reclaim the MOST database storage space?

AOption A

BOption B

COption C

DOption D

Show Suggested Answer

Suggested Answer: A

To reclaim the most storage space from a materialized view in Amazon Redshift, you should use a DELETE operation that removes all rows from the view. The most efficient way to remove all rows is to use a condition that always evaluates to true, such as 1=1. This will delete all rows without needing to evaluate each row individually based on specific column values like load_date.

Option A: DELETE FROM materialized_view_name WHERE 1=1; This statement will delete all rows in the materialized view and free up the space. Since materialized views in Redshift store precomputed data, performing a DELETE operation will remove all stored rows.

Other options either involve inappropriate SQL statements (e.g., VACUUM in option C is used for reclaiming storage space in tables, not materialized views), or they don't remove data effectively in the context of a materialized view (e.g., TRUNCATE cannot be used directly on a materialized view).

Amazon Redshift Materialized Views Documentation

Deleting Data from Redshift

by Goldie at Oct 23, 2024, 03:10 PM

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Lynelle

3 months ago

I’m not so sure about that, I’d double-check the options.

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Leandro

3 months ago

Totally agree with Armando, B is the way to go!

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Gearldine

3 months ago

Wait, can you really delete rows from a materialized view like that?

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Chantell

4 months ago

I think Option D might actually work better.

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Armando

4 months ago

Option B is the best choice for reclaiming space.

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William

4 months ago

I vaguely recall that `DROP` is the most effective way to free up space, but I wonder if there are any implications for the underlying data.

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Delmy

4 months ago

I’m a bit confused about the difference between `TRUNCATE` and `DELETE`. I think `TRUNCATE` is supposed to be more efficient for reclaiming space, but I’m not positive.

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Alonso

4 months ago

I feel like we practiced a similar question where we had to delete rows from a view. I think `DELETE` could work, but it might not reclaim as much space as `DROP`.

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Joana

5 months ago

I remember we discussed how materialized views can be tricky with storage. I think the `DROP` command might be the best option here, but I'm not entirely sure.

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Mona

5 months ago

I think the key here is understanding how materialized views work in Redshift. I'll draw on my knowledge of database concepts to determine the most efficient way to reclaim the storage space.

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Darnell

5 months ago

Option D looks promising - deleting the entire materialized view would definitely reclaim the most storage space. I'll double-check the other options, but that's my initial thought.

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