Snowflake DEA-C01 Practice Test - Questions Answers, Page 10
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Question 91

Data Engineer wants to analyze query performance & looking out for profiling information, He went to Query/Operator Details also called Profile Overview of Query Profile Interface & searching for statistics attributes around I/O. Which of the following information he can't get from there?
Explanation:
To help you analyze query performance, Query/Operator Details panel also called Profile overview panel provides two classes of profiling information:
· Execution time, broken down into categories
· Detailed statistics
Apart from Option à Bytes sent over the wireframe — amount of data sent over the wireframe , Rest of the Statistics Information provided by Query/Operator details in the Query Profile Inter-face.
To Know More about the Query/Operator Details options , please refer the link:
https://docs.snowflake.com/en/user-guide/ui-query-profile#query-operator-details
Question 92

What are Common Query Problems a Data Engineer can identified using Query Profiler?
Explanation:
"Exploding" Joins
One of the common mistakes SQL users make is joining tables without providing a join condition (resulting in a "Cartesian product"), or providing a condition where records from one table match multiple records from another table. For such queries, the Join operator produces significantly (often by orders of magnitude) more tuples than it consumes.
This can be observed by looking at the number of records produced by a Join operator in the profile interface, and typically is also reflected in Join operator consuming a lot of time.
Queries Too Large to Fit in Memory
For some operations (e.g. duplicate elimination for a huge data set), the amount of memory available for the compute resources used to execute the operation might not be sufficient to hold intermediate results. As a result, the query processing engine will start spilling the data to local disk.
If the local disk space is not sufficient, the spilled data is then saved to remote disks.
This spilling can have a profound effect on query performance (especially if remote disk is used for spilling).
Spilling statistics can be checked in Query Profile Interface.
Inefficient Pruning
Snowflake collects rich statistics on data allowing it not to read unnecessary parts of a table based on the query filters. However, for this to have an effect, the data storage order needs to be correlat-ed with the query filter attributes.
The efficiency of pruning can be observed by comparing Partitions scanned and Partitions total statistics in the TableScan operators. If the former is a small fraction of the latter, pruning is efficient. If not, the pruning did not have an effect.
Of course, pruning can only help for queries that actually filter out a significant amount of data. If the pruning statistics do not show data reduction, but there is a Filter operator above TableScan which filters out a number of records, this might signal that a different data organization might be beneficial for this query.
Question 93

Michael, a Data Engineer Running a Data query to achieve Union of Data sets coming from Multi-ple data sources, later he figured out that Data processing query is taking more time than expected. He started analyzing the Query performance using query profile interface. He discovered & realized that he used UNION when the UNION ALL semantics was sufficient.
Which Extra Data Processing Operator Michael figured out while doing query profile analysis in this case which helps him to identify this performance bottlenecks?
Explanation:
In SQL, it is possible to combine two sets of data with either UNION or UNION ALL constructs. The difference between them is that UNION ALL simply concatenates inputs, while UNION does the same, but also performs duplicate elimination.
A common mistake is to use UNION when the UNION ALL semantics are sufficient. These que-ries show in Query Profile as a UnionAll operator with an extra Aggregate operator on top (which performs duplicate elimination).
To Know more about Data Processing Operators, please do refer:
https://docs.snowflake.com/en/user-guide/ui-query-profile#operator-types
Question 94

Jonas, a Lead Performance Engineer,identifed that some of the operation of his query which functionally remove the duplicates from huge data set is spilling the data to remote disk. How can he alleviate spilling to a remote disk for better query performance?
Explanation:
For some operations (e.g. duplicate elimination for a huge data set), the amount of memory available for the compute resources used to execute the operation might not be sufficient to hold intermediate results. As a result, the query processing engine will start spilling the data to local disk.
If the local disk space is not sufficient, the spilled data is then saved to remote disks.
This spilling can have a profound effect on query performance (especially if remote disk is used for spilling). To alleviate this, It is recommend that:
· Using a larger warehouse (effectively increasing the available memory/local disk space for the operation), and/or Processing data in smaller batches.
Question 95

You as Data engineer might want to consider disabling auto-suspend for a warehouse if?
Explanation:
Automating Warehouse Suspension
Data Engineer might want to consider disabling auto-suspend for a warehouse if:
He/She have a heavy, steady workload for the warehouse.
He/She require the warehouse to be available with no delay or lag time. Warehouse provisioning is generally very fast (e.g. 1 or 2 seconds); however, depending on the size of the warehouse and the availability of compute resources to provision, it can take longer.
If he/she chose to disable auto-suspend, He/she must carefully consider the costs associated with running a warehouse continually, even when the warehouse is not processing queries. The costs can be significant, especially for larger warehouses (X-Large, 2X-Large, etc.).
To disable auto-suspend, Engineer must explicitly select Never in the web interface, or specify 0 or NULL in SQL.
Question 96

Harry using Snowflake Enterprise Edition & decided to scale in/out the Cluster in automatic mode.
He needs to configure some warehouses as multi cluster mode and some among them in Standard mode as per needs.
If Harry is using Snowflake Enterprise Edition (or a higher edition), all his warehouses should be configured as multi-cluster warehouses only.
Explanation:
If you are using Snowflake Enterprise Edition (or a higher edition), all your warehouses should be configured as multi-cluster warehouses.
Question 97

Ryan, a Data Engineer, wants to improve the performance of large, complex queries against large data sets. He decided to Scale up underlying warehouse/cluster. What is correct Snowflake consideration while scaling up so that he can achieve better performance results? [Select all that apply]
Question 98

While working with Multi Cluster Warehouses, Select the incorrect understanding of Data Engineer about its usage?
Question 99

Select the incorrect statement while working with warehouses?
Question 100

Ira a Data Engineer with TESLA IT systems, looking out to Compare Traditional Partitioning vs Snowflake micro-partitions for one of the Snowflake Project implementations. Which one of the following is incorrect understanding of Ira about Micro Partitioning?
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