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Databricks Certified Data Engineer Professional Exam - Topic 2 Question 24 Discussion

Actual exam question for Databricks's Databricks Certified Data Engineer Professional exam
Question #: 24
Topic #: 2
[All Databricks Certified Data Engineer Professional Questions]

A Delta Lake table representing metadata about content from user has the following schema:

user_id LONG, post_text STRING, post_id STRING, longitude FLOAT, latitude FLOAT, post_time TIMESTAMP, date DATE

Based on the above schema, which column is a good candidate for partitioning the Delta Table?

Show Suggested Answer Hide Answer
Suggested Answer: A

Partitioning a Delta Lake table improves query performance by organizing data into partitions based on the values of a column. In the given schema, the date column is a good candidate for partitioning for several reasons:

Time-Based Queries: If queries frequently filter or group by date, partitioning by the date column can significantly improve performance by limiting the amount of data scanned.

Granularity: The date column likely has a granularity that leads to a reasonable number of partitions (not too many and not too few). This balance is important for optimizing both read and write performance.

Data Skew: Other columns like post_id or user_id might lead to uneven partition sizes (data skew), which can negatively impact performance.

Partitioning by post_time could also be considered, but typically date is preferred due to its more manageable granularity.


Delta Lake Documentation on Table Partitioning: Optimizing Layout with Partitioning

by Rosalia at Sep 17, 2024, 12:54 AM

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Jackie
3 months ago
Really? I thought Post_id would be better for uniqueness.
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Georgene
3 months ago
Agreed, Date is the best for time-based queries.
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Maia
3 months ago
Wait, why not User_id? Seems like a good option!
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Marva
4 months ago
I think Post_time could work too, but not as efficient.
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Dick
4 months ago
Date is definitely a solid choice for partitioning.
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Sonia
4 months ago
I lean towards date as well, but I wonder if there are cases where post_id could be useful for partitioning, especially if posts are grouped by content type.
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Yoko
4 months ago
I practiced a similar question, and I think user_id might not be ideal for partitioning since it could lead to uneven data distribution.
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Lang
4 months ago
I'm not entirely sure, but I feel like post_time could also be a candidate since it captures the exact moment of the post.
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Germaine
5 months ago
I remember we discussed partitioning strategies, and I think date is often a good choice for time-series data.
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Dyan
5 months ago
I'm a little confused on the best approach here. I'll need to review the concepts of partitioning and how it can optimize queries on this type of data. Maybe I'll jot down a few notes and come back to this question.
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Melissia
5 months ago
Partitioning by User_id could be useful if we need to frequently query data for specific users. But Date seems like the most logical choice based on the question.
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Graciela
5 months ago
This seems like a straightforward question. I'd go with option A, Date, since that's a good way to partition the data and improve query performance.
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Candra
5 months ago
Hmm, I'm a bit unsure here. I'm thinking maybe Post_time could also be a good candidate for partitioning, since that's related to the content timeline. I'll have to think this through a bit more.
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Deane
5 months ago
Okay, let's break this down. The key is understanding how Magento stores the IDs of updated products for reindexing in "Update on Schedule" mode. I think option B sounds the most plausible.
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Gerald
1 year ago
Date is the best choice here. I mean, who doesn't love a good old-fashioned date partition? It's a classic for a reason.
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Kasandra
1 year ago
Partitioning by post_time is the way to go. It'll make your queries fly, especially if you're doing a lot of time-series analysis.
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Ayesha
1 year ago
Wait, why would anyone partition by post_id? That's just the unique identifier for each post, not a useful dimension.
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Mohammad
1 year ago
While post_time and date are good options, I think user_id could also be a good candidate for partitioning. Queries often focus on a specific user's data.
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Ashlyn
1 year ago
User4: Post_id could also be a good candidate for partitioning.
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Karan
1 year ago
User3: User_id might be a good choice too, since queries often focus on specific users.
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James
1 year ago
User2: Post_time could also work well for partitioning.
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Joaquin
1 year ago
User1: I think Date is the best option for partitioning.
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Jerlene
1 year ago
I would go with post_time. Partitioning by the timestamp of the post would allow for efficient queries based on time periods.
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Raul
1 year ago
The date column seems like the obvious choice for partitioning the Delta table. It's a common way to partition data based on time.
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Loreta
1 year ago
D) Post_time
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Jesusita
1 year ago
C) User_id
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Samira
1 year ago
B) Post_id
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Roslyn
1 year ago
A) Date
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Kiera
1 year ago
Date for sure! Unless you're a time traveler, in which case Post_time might be the way to go.
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Keneth
1 year ago
Hmm, I'm not sure. Maybe User_id would be a good choice if you want to analyze the data by individual users.
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Terrilyn
1 year ago
User3: Post_time might be a good option for organizing data by time.
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Denny
1 year ago
User2: User_id could work well for analyzing data by individual users.
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Marvel
1 year ago
User1: I think Date would be a good choice for partitioning.
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Marylyn
1 year ago
I think Post_id could also be a good candidate for partitioning to group related posts together.
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Kasandra
1 year ago
I agree with Tish, Date would be a good choice for partitioning to optimize queries based on time.
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Nettie
1 year ago
I'd go with Post_time. Partitioning by the timestamp of the post seems more relevant than just the date.
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Tish
1 year ago
I think Date is a good candidate for partitioning because it can help with time-based queries.
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Dottie
1 year ago
I think the best column for partitioning would be Date. It's a common way to partition tables and makes sense for this use case.
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Carissa
1 year ago
Post_time could also work well for partitioning, depending on the query patterns.
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Gilbert
1 year ago
D) Post_time
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Rozella
1 year ago
I agree, Date would be a good choice for partitioning in this case.
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Kami
1 year ago
A) Date
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