The answer is that the FULLTEXT index creation failed because the column's length exceeds the maximum allowed limit. In RDS MySQL, FULLTEXT indexes have a strict column length limitation: 1000 bytes for InnoDB tables and 1000 characters for MyISAM tables. When a column like 'description' stores long text that surpasses this threshold, the database engine cannot build the index, resulting in an error. On the AWS Certified Database Specialty DBS-C01 exam, this question tests your understanding of MySQL storage engine constraints and how they interact with RDS configurations. A common trap is assuming the failure is due to permissions, table locks, or character set issues, but the error log pointing to a creation failure without other configuration problems strongly signals a length violation. Remember the memory tip: "Fulltext fails at a thousand" — for InnoDB, think bytes; for MyISAM, think characters.
DBS-C01 Workload-Specific Database Design Practice Question
This DBS-C01 practice question tests your understanding of workload-specific database design. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Exhibit
Refer to the exhibit.
=== Amazon RDS MySQL Error Log ===
2023-03-15 10:45:12 123456 [ERROR] [MY-013142] [Server] InnoDB: Table 'mydb.orders' has a FULLTEXT index on column 'description'. The maximum column length for FULLTEXT index is 4294967295. However, the column length is 4294967295 which may cause performance issues.
2023-03-15 10:45:12 123456 [ERROR] [MY-010067] [Server] Cannot create FULLTEXT index on column 'description' because the column is too long.
A developer is trying to create a FULLTEXT index on a column in an RDS MySQL instance. The error log shows the index creation failed. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Refer to the exhibit.
=== Amazon RDS MySQL Error Log ===
2023-03-15 10:45:12 123456 [ERROR] [MY-013142] [Server] InnoDB: Table 'mydb.orders' has a FULLTEXT index on column 'description'. The maximum column length for FULLTEXT index is 4294967295. However, the column length is 4294967295 which may cause performance issues.
2023-03-15 10:45:12 123456 [ERROR] [MY-010067] [Server] Cannot create FULLTEXT index on column 'description' because the column is too long.
A
The column 'description' has a length that exceeds the maximum allowed for FULLTEXT index.
The error states the column length is 4294967295, which is too large.
B
The table size is too large for a FULLTEXT index to be created.
Why wrong: Table size is not the issue; it's the column length.
C
The table uses a character set that is not compatible with FULLTEXT indexes.
Why wrong: No character set incompatibility is mentioned.
D
The InnoDB engine does not support FULLTEXT indexes.
Why wrong: InnoDB supports FULLTEXT indexes since MySQL 5.6.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The column 'description' has a length that exceeds the maximum allowed for FULLTEXT index.
In RDS MySQL, FULLTEXT indexes have a maximum column length limit of 1000 bytes for InnoDB and 1000 characters for MyISAM. If the 'description' column exceeds this limit, the index creation will fail. This is the most likely cause because the error log indicates a failure without other configuration issues.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
The column 'description' has a length that exceeds the maximum allowed for FULLTEXT index.
Why this is correct
The error states the column length is 4294967295, which is too large.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The table size is too large for a FULLTEXT index to be created.
Why it's wrong here
Table size is not the issue; it's the column length.
✗
The table uses a character set that is not compatible with FULLTEXT indexes.
Why it's wrong here
No character set incompatibility is mentioned.
✗
The InnoDB engine does not support FULLTEXT indexes.
Why it's wrong here
InnoDB supports FULLTEXT indexes since MySQL 5.6.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume InnoDB does not support FULLTEXT indexes (a common misconception from older MySQL versions) or that table size is the issue, but the actual constraint is the column length limit.
Detailed technical explanation
How to think about this question
The 1000-byte limit for InnoDB FULLTEXT indexes stems from the internal storage of the inverted index, where each word's position and document ID are stored in a fixed-size structure. In practice, if you need to index a longer text column, you can use a separate column with a VARCHAR(1000) or TEXT column and apply the FULLTEXT index on a prefix or use a workaround like splitting the text into multiple indexed columns.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Workload-Specific Database Design — This question tests Workload-Specific Database Design — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The column 'description' has a length that exceeds the maximum allowed for FULLTEXT index. — In RDS MySQL, FULLTEXT indexes have a maximum column length limit of 1000 bytes for InnoDB and 1000 characters for MyISAM. If the 'description' column exceeds this limit, the index creation will fail. This is the most likely cause because the error log indicates a failure without other configuration issues.
What should I do if I get this DBS-C01 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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