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Exam AWS Certified Database - Specialty topic 1 question 100 discussion

Exam question from Amazon's AWS Certified Database - Specialty
Question #: 100
Topic #: 1
[All AWS Certified Database - Specialty Questions]

A company is using Amazon Aurora PostgreSQL for the backend of its application. The system users are complaining that the responses are slow. A database specialist has determined that the queries to Aurora take longer during peak times. With the Amazon RDS Performance Insights dashboard, the load in the chart for average active sessions is often above the line that denotes maximum CPU usage and the wait state shows that most wait events are IO:XactSync.
What should the company do to resolve these performance issues?

  • A. Add an Aurora Replica to scale the read traffic.
  • B. Scale up the DB instance class.
  • C. Modify applications to commit transactions in batches.
  • D. Modify applications to avoid conflicts by taking locks.
Show Suggested Answer Hide Answer
Suggested Answer: B 🗳️
by std2021 at April 1, 2021, 9:04 p.m.
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Huy
Highly Voted 3 years, 6 months ago
C is answer. https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/AuroraPostgreSQL.Reference.html. Check frank's link.
upvoted 12 times
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frankzeng
Highly Voted 3 years, 6 months ago
C https://blog.dbi-services.com/aws-aurora-xactsync-batch-commit/
upvoted 11 times
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Hisayuki
Most Recent 1 year, 3 months ago
Selected Answer: B
IO:XactSync with high CPU wait - means DB load exceed allocated vCPUs, so you should reduce those workloads or scale up to higher CPUs But if the IO:XactSync is due to high commit, then you should modify your application to commit transactions in batches
upvoted 1 times
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jitesh_k
1 year, 4 months ago
Answer seems C since IO:Xactsync is about commit/rollback. https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/apg-waits.xactsync.html Batch commit seems to be the answer.
upvoted 1 times
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jitesh_k
1 year, 4 months ago
Why not A? Add Aurora replica.
upvoted 3 times
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Pranava_GCP
1 year, 8 months ago
Selected Answer: B
B. Scale up the DB instance class. https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/apg-waits.xactsync.html#apg-waits.xactsync.actions.scalecpu
upvoted 1 times
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IhorK
1 year, 8 months ago
According to https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/apg-waits.xactsync.html we should - Scale up the CPU; - Reduce the number of commits. There are 2 correct answers: B and C. I don't know who to give preference to :(
upvoted 2 times
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[Removed]
1 year, 10 months ago
Selected Answer: B
Hard choice between B&C, but i select B. AWS recommends in documentation ( https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/apg-waits.xactsync.html ) to Scale up the CPU or Reduce the number of commits. Modify application will require some time -> therefore Scaling up will help to resolve current issues with CPU
upvoted 1 times
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Zdujgfr567783ff
1 year, 10 months ago
Selected Answer: C
By default in PostgreSQL, single-row inserts auto-commit for each row. This means that the database must wait for durability (write to storage) for every insert. To improve performance, PostgreSQL supports multi-row inserts and disabling auto-commit.
upvoted 1 times
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Zdujgfr567783ff
1 year, 10 months ago
C By default in PostgreSQL, single-row inserts auto-commit for each row. This means that the database must wait for durability (write to storage) for every insert. To improve performance, PostgreSQL supports multi-row inserts and disabling auto-commit.
upvoted 1 times
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Pankaj24hrs
1 year, 11 months ago
B If CPU would not be an issue then definitely C, since a high CPU then it effects writing to the Storage layer as well. CPU pressure A heavy workload might be preventing the Aurora storage daemon from getting sufficient CPU time. To address CPU starvation issues, consider changing to an instance type with more CPU capacity
upvoted 1 times
Zdujgfr567783ff
1 year, 10 months ago
why CPU? IO:XactSync. PDF RSS. The IO:XactSync event occurs when the database is waiting for the Aurora storage subsystem to acknowledge the commit of a regular transaction, or the commit or rollback of a prepared transaction.
upvoted 1 times
Zdujgfr567783ff
1 year, 10 months ago
By default in PostgreSQL, single-row inserts auto-commit for each row. This means that the database must wait for durability (write to storage) for every insert. To improve performance, PostgreSQL supports multi-row inserts and disabling auto-commit.
upvoted 1 times
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guau
2 years, 2 months ago
Selected Answer: C
After reading the comments C is the right answer
upvoted 2 times
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anantarb
2 years, 2 months ago
Selected Answer: C
https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/apg-waits.xactsync.html#apg-waits.xactsync.actions.commits
upvoted 3 times
Mintwater
2 years, 1 month ago
vote for you! C
upvoted 2 times
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tucobbad
2 years, 4 months ago
Selected Answer: B
(with typos fixed) My answer is B. Despite we know that CPU is related to it as well as COMMIT frequency is high, tell me honestly what would be the fastest/easiest approach here to resolve the issue? Scale up the instance (B) or Modify an application to commit in batches (C). Second, this post by Franck Pachot has plenty info which basically leds to CPU issue: https://www.dbi-services.com/blog/aws-aurora-xactsync-batch-commit/
upvoted 3 times
Sathish_dbs
2 years, 3 months ago
There is no ask about fastest/easiest approach here. so as a company the best approach to be taken here which is fixing the performance issue in the code. you can't keep increasing the hardware forever without fixing the code first!
upvoted 2 times
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tucobbad
2 years, 4 months ago
Selected Answer: B
My answer is B. Despite we know that CPU is related to it as well as COMMIT frequency is high, tell me honestly what would be the fastest/easiest approach here to resolve the issue? Scale up the instance (B) or Modify an application to commit in batches (C). Second, this post by Frank Pachot has planty info which basically leds to CPU issue: https://www.dbi-services.com/blog/aws-aurora-xactsync-batch-commit/
upvoted 1 times
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bikash7758
2 years, 5 months ago
C IS CORRECT
upvoted 2 times
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rags1482
2 years, 6 months ago
Answer : C
upvoted 2 times
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