1z0-915-1 Practice Exam Questions with Answers MySQL HeatWave Implementation Associate Rel 1 Certification

To deploy a high-availability MySQL DB system in a region with multiple availability domains, the following types of subnets provide maximum redundancy:

A private regional subnet(Answer B): This type of subnet spans all availability domains in the region, ensuring high availability and fault tolerance.

A public regional subnet(Answer C): Similar to the private regional subnet, a public regional subnet spans all availability domains, providing maximum redundancy and accessibility.

References:

OCI Networking Documentation

MySQL High Availability Documentation

B.ENGINE=csv SECONDARY_ENGINE=lakehouse ENGINE_ATTRIBUTE=’{"file": [{"region": "us-ashburn-1", "namespace": "mytenant", "bucket": "bucket01", "name": "airport.csv"}] }’: This table option defines a Lakehouse external table based on a CSV file. It specifies thecsvengine for the table and uses thelakehouseas the secondary engine, along with the file's location details in OCI Object Storage.

To use the point-in-time recovery feature in a DB system,automatic backupsmust be enabled (Answer B).

Point-in-Time Recovery: This feature allows you to restore your database to a specific point in time, which is crucial for recovering from accidental data loss or corruption.

Automatic Backups: These provide the necessary backup data that can be used to restore the database to the desired point in time.

References:

OCI MySQL Database Service Point-in-Time Recovery

Automatic Backups Documentation

The following are true about the read replica load balancer:

It distributes connections among the source DB system and all read replicas(Answer B): The load balancer distributes incoming read traffic across all read replicas and the source DB system to balance the load and improve performance.

It distributes connections among read replicas(Answer E): The load balancer ensures that read traffic is evenly distributed among all available read replicas, providing high availability and scalability for read operations.

References:

OCI MySQL Database Service Read Replicas Documentation

When creating a Bastion service to connect to a MySQL DB system, the following are true:

The Bastion CIDR block allowlist must include the IP address of all valid client machines(Answer C): This ensures that only the IP addresses specified in the allowlist can access the Bastion service, enhancing security by restricting access to known clients.

The Bastion subnet must have an ingress rule to allow stateful connections on the MySQL DB system port number(Answer E): This allows the Bastion service to communicate with the MySQL DB system by permitting traffic through the necessary ports.

References:

OCI Bastion Service Documentation

Setting Up Bastion with MySQL DB System

Based on the provided SQL statements, the following two are true:

The data placement key of the airport table is airport_id(Answer A): The primary keyairport_idis used as the data placement key in theairporttable. This means that the data in the table is organized based on theairport_idvalues.

The data of the airport table is loaded into the MySQL DB system(Answer D): TheALTER TABLE airport SECONDARY_LOAD;statement successfully loads the data from the specified object storage file into the MySQL DB system.

References:

MySQL HeatWave Documentation

MySQL Engine Attributes

To offload the second query to the HeatWave cluster for execution, you can use the following methods:

SET use_secondary_engine=FORCED(Answer A): This forces the use of the HeatWave secondary engine for query execution, regardless of the estimated cost.

SET secondary_engine_cost_threshold=1000(Answer B): This lowers the cost threshold for queries to be offloaded to the HeatWave cluster, allowing queries with lower estimated costs to be offloaded.

Steps:

Before running the second query, executeSET use_secondary_engine=FORCED;to force the offloading of queries to HeatWave.

Alternatively, executeSET secondary_engine_cost_threshold=1000;to adjust the cost threshold, making the second query eligible for offloading.

When changing the storage size of a DB system,you cannot decrease the DB system's storage size(Answer B). This restriction ensures data integrity and prevents potential data loss that could occur if the storage size were reduced.

You can only increase the storage size of the DB system.

The storage increase is done online without shutting down the DB system, allowing for uninterrupted operations.

References:

OCI MySQL DB System Scaling Documentation

To speed up the data load into a DB system usingMySQL Shell util.loadDump(), you can use thedeferTableIndexes: alloption (Answer D). This option defers the creation of indexes until after the data has been loaded, which can significantly improve the speed of the loading process.

Steps:

Export your data using MySQL Shell dump utility.

Useutil.loadDump()to import the data and specify thedeferTableIndexes: alloption.

The data is loaded without building indexes initially, reducing the time required for the import.

After the data load is complete, indexes are created in a batch process, which is more efficient than creating them during the data load.

References:

MySQL Shell Dump & Load Documentation

To determine whether a query is offloaded to the HeatWave cluster for execution,check the value of therapid_query_offload_countglobal status variable(Answer B).

rapid_query_offload_count: This variable indicates the number of queries that have been offloaded to the HeatWave cluster. By checking its value before and after running the query, you can determine if the query was offloaded.

Steps:

Connect to the MySQL DB system.

RunSHOW GLOBAL STATUS LIKE 'rapid_query_offload_count';before and after executing the query to see if the count increases, indicating offloading.

References:

MySQL HeatWave Documentation

Monitoring HeatWave Status Variables

Initialization variables(Answer A) cannot be modified in MySQL custom configurations. These variables are set at the start of the MySQL service and are not changeable without restarting the service.

Initialization variables are parameters that define how the MySQL server initializes.

Changes to these variables require restarting the MySQL server to take effect.

Examples include variables likeinnodb_buffer_pool_size, which determine memory allocation settings on startup.

References:

MySQL Configuration Variables Documentation

The statementsCALL sys.ML_TRAIN(‘ml_data.iris’, ‘class’, NULL, @model);andSELECT @model;are used to create and retrieve a machine learning model in MySQL HeatWave AutoML. The following are true:

The generated model handle is shown in the output(Answer B): After training the model, the handle (identifier) for the model is stored in the@modelvariable and can be retrieved with theSELECT @model;statement.

The statements create a classification model(Answer C): TheML_TRAINprocedure is used to create a classification model since the target column (class) indicates a classification problem.

The target column is class(Answer E): The second argument in theML_TRAINcall specifies the target column for the machine learning model, which isclassin this case.

References:

MySQL HeatWave AutoML Documentation

ML_TRAIN Procedure Documentation

The commandmysqlsh john@10.0.1.122 --auth-method=authentication_oci_clientdoes not require a password because it uses the OCI (Oracle Cloud Infrastructure) client authentication method. This method relies on the correct API key-pair specified in the~/.oci/configfile. This file contains the necessary credentials (user OCID, tenancy OCID, API keys, etc.) to authenticate with the OCI environment without needing a password for each connection.

When creating a new MySQL DB system in the OCI Console, you have the following options:

High availability(Answer A): This option allows you to create a DB system that can automatically fail over to a standby instance in case of hardware or software failure, ensuring minimal downtime.

Standalone server(Answer C): This option lets you create a DB system with a single instance, suitable for workloads that do not require high availability or read replicas.

References:

OCI MySQL Database Service Documentation

MySQL High Availability