1z0-915-1 Questions and Answers

When creating a channel for replication in MySQL, the following must be provided:

Channel name(Answer A): The unique identifier for the replication channel.

Source connection SSL mode(Answer B): Specifies the SSL mode for the connection to the source server.

Source connection password(Answer D): The password for the source server connection.

Steps:

UseCHANGE MASTER TOcommand to set up the replication channel.

Provide the channel name, SSL mode, and connection password as part of the configuration.

References:

MySQL Replication Documentation

Setting Up Replication Channels

When performing a node estimate while adding a HeatWave cluster to a DB system in OCI Console, the process undertakes the following tasks:

Estimate the number of OCPUs required to process selected user tables(Answer B): The node estimation process calculates the necessary OCPUs based on the size and complexity of the tables selected by the user. This ensures that the cluster has adequate processing power for efficient performance.

Estimate the memory required for each user table(Answer C): This task involves determining the memory requirements for each table that will be loaded into the HeatWave cluster. This ensures that there is sufficient memory to handle the data and execute queries efficiently.

References:

OCI Console Documentation on HeatWave

MySQL HeatWave User Guide

To connect to a MySQL DB system using MySQL Shell, you can use several command-line formats. Here, we will analyze the provided options:

A.mysqlsh -h 10.0.1.221 -u admin -p MySQL8.0

Incorrect format. The password should not be directly placed after the-pflag without a space or equals sign.

B.mysqlsh mysql://MySQL8.0:admin@10.0.1.221

Incorrect format. The username should come before the password in the URL.

C.mysqlsh mysql://admin:MySQL8.0@10.0.1.221

Correct format. This is a valid way to connect using a URL-like format whereadminis the username,MySQL8.0is the password, and10.0.1.221is the host.

D.mysqlsh -h10.0.1.221 -uadmin -pMySQL8.0

Correct format. This is a valid way to connect using flags, with no spaces between the flags and their values.

E.mysqlsh -host 10.0.1.221 -user admin -password MySQL8.0

Incorrect format. MySQL Shell uses-h,-u, and-pfor specifying host, username, and password respectively.

You can determine the uptime of a DB system bychecking the DB system details in the OCI Web console(Answer B). The console provides information on the system status, including the uptime since the last start.

Steps:

Log in to the OCI Web console.

Navigate to the MySQL DB system.

View the details page of the DB system, where the uptime information is displayed.

References:

OCI Console Documentation

Monitoring DB System Uptime

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 train a model that predicts sales, the appropriate machine learning task would be regression, as it involves predicting a continuous value (sales) based on the given data. The command to train such a model is:

D.CALL sys.ML_TRAIN('ml_data.sales', 'Sales', JSON_OBJECT('task', 'regression'), @model);

This command calls theML_TRAINprocedure on theml_data.salestable, withSalesas the target variable, specifying the task as regression.

Given the SSH command sets up port forwarding from the local port3311to the remote MySQL DB system port3306, the correct command to connect to the MySQL DB system from the client machine is:

C.mysqlsh mysql://admin@127.0.0.1:3311

This command connects to the local machine's port3311, which forwards the connection to the MySQL DB system at10.10.1.187:3306.

To connect to a MySQL DB system from an OCI Cloud Shell session when the VCN is not configured with VCN peering, VPN access, or FastConnect, the following must be true:

A.You must attach the Cloud Shell session to a VCN subnet that can connect to the MySQL DB system: The Cloud Shell must be in the same network or have a route to the network containing the MySQL DB system. C.The MySQL DB system subnet must be in theCloud Shell tenancy home region: Cloud Shell sessions operate within the OCI home region, so the target MySQL DB system must be accessible from within the same region.

In a high-availability DB system, the placement of primary and secondary instances should ensure redundancy across different availability domains (ADs) and fault domains (FDs) to minimize downtime and data loss. The placement mentioned in option D is not valid because itplaces the primary and secondary instances in the same availability domain and fault domain, which does not provide high availability.

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

A.Reduce query latency: By distributing read queries across multiple replicas, the load on the primary instance is reduced, which can decrease query latency. D.Scale read queries: Read replicas allow scaling of read operations by providing additional instances to handle read queries, improving overall performance and throughput.

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.

The MySQL HeatWave AutoML routine that evaluates a model isML_SCORE. This routine scores a trained machine learning model on a new dataset and evaluates its performance.

For a MySQL DB system with five active read replicas and a workload consisting mostly of reads, the fastest query response time is achieved by:

C.Connect to the read replica load balancer to perform read-only operations: The read replica load balancer distributes the read workload across all replicas, optimizing performance and response time.