1z0-915-1 Sample Questions Answers

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

Before enabling a MySQL HeatWave cluster,you must create a DB system with a HeatWave shape(Answer D). The HeatWave shape includes the necessary resources and configuration to support the HeatWave in-memory query accelerator.

Steps:

Create a MySQL DB system in OCI Console.

Choose a HeatWave shape during the DB system creation process.

Once the DB system is created, you can enable and configure the HeatWave cluster.

References:

MySQL HeatWave Documentation

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.

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

When creating a custom configuration for the MySQL DB system in OCI Console, you can set the following:

A.Shape: This defines the compute resources (CPU, memory) allocated to the DB system. B.VCN (Virtual Cloud Network): This defines the network in which your DB system will be placed. E.Compartment: This is an OCI resource management feature that allows you to organize and isolate your cloud resources.

If you cannot connect directly to the MySQL DB system endpoint from your workstation connected to the Internet, the reason is thatMySQL DB system endpoint does not have a public IP address(Answer B).

Private Subnet: The MySQL DB system is provisioned in a private subnet, which means it is not directly accessible from the Internet.

Network Accessibility: To access the DB system, you need to establish a secure connection via a VPN, FastConnect, or SSH tunnel.

References:

Connecting to a MySQL DB System

OCI Networking Documentation

To create a connection in Database Tools to use the SQL Worksheet feature, the following steps are required:

Create an OCI password(Answer A): This password is necessary for authentication when connecting to the MySQL DB system.

Create an OCI secret(Answer D): Secrets are used to store sensitive information like passwords securely. The secret will contain the database credentials.

Import an X.509 certificate into the OCI vault(Answer E): This certificate is required for secure connections to the database, ensuring encrypted communication.

References:

OCI Database Tools Documentation

Using OCI Secrets

X.509 Certificates 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

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.

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.

The error message indicates that the source has purged required binary logs, making it impossible to replicate the missing transactions. This happens when the administrator manually deletes binary log files from the source DB system, or the binary log expiration period is too short, causing automatic purging before the replica can fetch the transactions.

A query may not be offloaded to the HeatWave cluster for execution due to the following reasons:

A.Theuse_secondary_enginesession variable is OFF: This setting controls whether queries should be offloaded to the secondary engine (HeatWave). B.The client is connected to the DB system instead of the HeatWave cluster: For queries to be offloaded, the client must be connected to the HeatWave cluster. E.A required column is excluded from the RAPID secondary engine: If a necessary column is not available in the HeatWave (RAPID) secondary engine, the query cannot be offloaded.

Creating a new DB system with data import provides the benefit of faster import with minimal logging. This process is optimized to import large datasets efficiently and quickly, reducing the amount of logging overhead and ensuring a rapid setup of the new DB system.

To enable high availability for a stand-alone DB system, the following conditions are required:

The DB system must be active(Answer D): The DB system needs to be in an active state to enable high availability features.

The DB system automatic backup must be enabled(Answer E): Automatic backups must be enabled to ensure data protection and facilitate failover operations.

Steps:

Ensure the DB system is running and operational.

Enable automatic backups through the OCI Console or API.

References:

MySQL High Availability Documentation

Automatic Backups Documentation

To minimize DB system downtime caused by automatic maintenance operations, you should enable high availability. High availability ensures that there are multiple instances of your database running in different fault domains or availability domains, reducing the impact of maintenance on the system's availability.

To replicate data from an on-premises MySQL server to a MySQL DB system running in Oracle Cloud Infrastructure (OCI), where the DB system is connected to a private subnet of a Virtual Cloud Network (VCN), you need to enable the DB system to communicate with the Internet securely. The correct configuration is tocreate a NAT gateway in the VCN and configure the DB system subnet to route Internet-bound traffic to the NAT gateway(Answer D).

NAT Gateway: A Network Address Translation (NAT) gateway enables instances in a private subnet to initiate outbound traffic to the Internet, but it prevents the Internet from initiating connections to those instances.

Route Table Configuration: You need to update the route table for the private subnet to direct traffic destined for the Internet to the NAT gateway.

Steps:

Create a NAT gateway in the OCI Console.

Update the route table associated with the private subnet to include a route rule that directs all Internet-bound traffic (0.0.0.0/0) to the NAT gateway.

References:

OCI NAT Gateway Documentation

Configuring Routing for Private Subnets