Performance Analysis

Question 1

Which of the following traces is active after the SAP HANA installation is complete

Answer 1

Database

Question 2

You are logged onto a customer’s Hana DB through the studio during a service and even simple operations become slower and slower. You begin to check the system to see if there is an issue. Which of the following makes sense to analyze in this situation

Answer 2

1. You check the threads tab to see if there are are any long running threads
2. You check the threads tab to see if there are any blocked threads
3. You check the load graph to see if there are any CPU spikes

Question 3

what is one of the main differences between the load graph in the HANA studio and the load graph in the HANA cockpit?

Answer 3

In the cockpit load graph you can select the show jobs option to highlight jobs that correlate with a resource spike

Question 4

A customer sets a statement memory limit on their HANA DB of 100GB. They observe occasions where queries are terminating at times of low overall memory usage and enquire about a method that allows queries to continue when memory usage is below a defined percentage. What is recommended they apply to achieve this

Answer 4

Apply the parameter “statement_memory_limit_threshold”

Question 5

You analyze a system with a CPU spike at a specific time. You use the thread sampling SQL scripts to obtain thread information during this spike which of the following metrics may be useful in determining root cause from the results returned

Answer 5

1. Number of samples
2. Thread details
3. Statement Hash

Question 6

There are 2 lock types for application transaction in HANA. What are they

Answer 6

1. Object

2. Record

Question 7

Analysis is required on a HANA database where the memory usage of the SQL plan cache is quite high and there are thousands of evictions per hour. You analyse the cache and see that a majority of the queries are to one table in particular and the WHERE clause has literal values. What may you recommend to the customer as a permanent solution for this issue

Answer 7

Use BIND variables in the where clause

Question 8

During a Going Live Service you analyse the SQL cache. You see that there are in excess of 1500 cache evictions per hour on all the hosts and each of them have a percentage of 99. Each cache is 2GB and hit ratios are all above 95%. What is your understanding of cache evictions in this context

Answer 8

The cache may be too small due to a large variety of statements and evictions occur to make space for new plans

Question 9

You want to track all queries that exceed a defined threshold. What trace do you activate on the HANA database

Answer 9

Expensive statement trace

Question 10

A query is taking 2 minutes longer to execute than pervious executions. You decide that a graphical representation of this queries execution would be helpful for analysis. What do you perform to achieve this

Answer 10

Plan Visualiser

Question 11

The diagnosis files contain trace files that are continuously filled with information about system operations. In a scale out system with 1 master and 2 slave nodes. Which of the following statements are true

Answer 11

Each service on each host has its own set of trace files

Each service also has its own alert trace file for high priority messages

Question 12

Which 2 of the following conditions should be met in order for a row store reorganization to be carried out when a row store has become fragmented

Answer 12

Row store size greater than 10GB

Free space ratio is greater than 30%