Practice Test 2 | Google Cloud Certified Professional Data Engineer | Dumps | Mock Test
The development team decided to use BigTable to write thousands of incoming stream data. Their choice was based on BigTable’s high performance and high throughput and low latency. However, the team is facing less than expected performance from the cluster. You are asked for advice on the reason for BigTable’s instance performance issue.
Which of the following can be a reason for the performance issue of BigTable cluster?
Choose 2 Options.
A. Row key used is increased monotonically.
B. Rows are less than 10MB of size.
C. HDD disk is used in the BigTable cluster.
D. Cluster is launched in a region different than where users reside.
Answer: A & C.
The most common issue for time series in Cloud Bigtable is hotspotting. This issue can affect any type of row key that contains a monotonically increasing value. In brief, when a row key for a time series includes a timestamp, all of your writes will target a single node; fill that node; and then move onto the next node in the cluster, resulting in hotspotting. Because Cloud Bigtable stores adjacent row keys on the same server node, all writes will focus only on one node until that node is full, at which point writes will move to the next node in the cluster.
BigTable instances are best performed with big size of data and SSD.
URN: https://cloud.google.com/bigtable/docs/performance#testing
Answer B is incorrect: You can read and write larger amounts of data per row, but increasing the amount of data per row will also reduce the number of rows per second. So, having rows with small size is better.
Answer D is incorrect: While selecting a region has an impact on network performance, it doesn’t affect BigTable’s performance when reading and writing data. It impacts the replication of data in the region
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URN: https://cloud.google.com/bigtable/docs/performance#performance-replication
When you use multi-cluster routing, replication for Bigtable is eventually consistent. As a general rule, it takes longer to replicate data across a greater distance. Replicated clusters in different regions will typically have higher replication latency than replicated clusters in the same region.
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Source(s):
Understanding BigTable Performance:
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