CCB-400 Online Practice Questions and Answers
You have one primary HMaster and one standby. Your primary HMaster Falls fails and your client application needs to make a metadata change. Which of the following is the effect on your client application?
A. The client will queryZooKeepertofind the location of the new HMaster and complete the metadata change.
B. The client will make the metadata change regardless of the slate of the HMaster.
C. The new HMaster will notify the client and complete the metadata change.
D. Theclientapplication will fail with a runtime error.
Under default settings, which feature of HBase ensures that data won't be lost in the event of a RegionServer failure?
A. AllHBase activity is written to the WAL, which is stored in HDFS
B. All operations are logged on theHMaster.
C. HBase is ACID compliant, which guarantees that itis Durable.
D. Data is stored on the local filesystem of the RegionServer.
You need to free up disk space on your HBase cluster. You delete all versions of your data that is older than one week. You notice your delete has had minimal impact on your storage availability. This is because:
A. You have large store file indexes
B. HBase has not flushed the MemStore
C. HBasehas not run a minor compaction
D. HBase has notrun a major compaction
Given the following HBase table schema:
Row Key, colFam_A:a, colFam_A:b, colFamB:2, colFam_B:10
A table scan will return the column data in which of the following sorted orders:
A. Row Key, colFam_A:a, colFam__A:b, colFam_B:10, colFam_B:2
B. Row Key, colFam_A:a, colFam__A:b,colFam_B:2, colFam_B:10
C. Row Key, colFam_A:a, colFam__B:2, colFam_A:b, colFam_B:10
D. Row Key, colFam_A:a, colFam__B:10, colFam_A:b, colFam_B:2
Your HBase cluster has hit a performance wall and doesn't seem to be getting faster as you add
RegionServers. Adding an additional HMaster will:
A. Have no effect on performance.
B. Improve the performance of region writes but decreasethe performance of metadata changes.
C. Improve the performance of metadata chancier, but decrease the performance of region writes.
D. Make theperformance problem even worse, as operations will have to be replicated to multiplemasters.
You have a total of three tables stored in HBase. Exchanging catalog regions, how many regions will your RegionServers have?
A. Exactly three
B. Exactly one
C. At least one
D. Atleastthree
Yon are storing page view data for a large number of Web sites, each of which has many subdomains (www.example.com, archive.example.com, beta.example.com, etc.) Your reporting tool needs to retrieve the total number of page views for a given subdomain of a Web site. Which of the following rowkeys should you use?
A. The reverse domain name (e.g., com.example.beta)
B. The domain name followed by the URL
C. The URL
D. The URL followed by the reverse domain name
Your client is writing to a region when the RegionServer crashes. At what point in the write is your data secure?
A. From the moment the RegionServer wrote to the WAL (write-ahead log)
B. From the moment the RegionServer returned the call
C. From the moment the RegionServer received the call
D. From the moment the RegionServer wrote to the MemStore
You want to do mostly full table scans on your data. In order to improve performance you increase your block size. Why does this improve your scan performance?
A. It does not. Increasing block size does not improve scan performance.
B. It does not. Increasing block size means that fewer blocks fit into your block cache. This requires HBase to read each block from disk rather than cache for each scan, thereby decreasing scan performance.
C. Increasing block size requires HBase to readfrom disk fewer times, thereby increasing scan performance.
D. Increasing block size means fewer block indexes that need to be read from disk, therebyincreasing scan performance.
Your client application needs to write a row to a region that has, recently split. Where will the row be written?
A. One of the daughter regions
B. The original region
C. The .META. table
D. The HMaster