PCD Practice Test 3 — 10 Questions

Question 1

A company wants to migrate an on-premises MySQL database to Cloud SQL with minimal downtime. Which two steps should they take? (Choose two.)

Accepted Answer

Use Database Migration Service to create a continuous replication job. Option A is correct because Database Migration Service (DMS) supports continuous replication from an on-premises MySQL source to Cloud SQL, keeping the target in sync so the cutover can happen with minimal downtime. Option D is correct because DMS continuous replication relies on the source MySQL binary log (binlog) to capture ongoing changes; binary logging must be enabled (with a suitable binlog_format such as ROW) for replication to work. Options B, C, and E are not required: the Cloud SQL Auth Proxy is used by clients to connect securely to Cloud SQL, not on the source database; a full backup/restore is part of the initial snapshot that DMS handles automatically, not a separate required step; and disabling foreign key checks on the source is neither necessary nor advisable for a migration.

Answer

Set up a Cloud SQL proxy on the source database

Answer

Take a full backup and restore it to Cloud SQL before replication

Answer

Disable foreign key checks on the source database

Question 2

An organization is migrating from Oracle to Cloud SQL for PostgreSQL. They need to convert Oracle packages (which use PL/SQL) into PostgreSQL equivalents. Which TWO approaches are correct for handling Oracle packages?

Accepted Answer

Rewrite PL/SQL code into PL/pgSQL syntax.. Option A is correct because Oracle packages contain PL/SQL code, and Cloud SQL for PostgreSQL executes procedural logic in PL/pgSQL, so the package bodies must be manually rewritten into PL/pgSQL syntax (including converting constructs like %TYPE, %ROWTYPE, and Oracle-specific built-ins). Option D is correct because PostgreSQL has no native package object; the standard migration pattern is to map each Oracle package to a dedicated PostgreSQL schema that groups the equivalent functions and procedures, preserving the package's namespace and encapsulation. Option B is wrong because pgAgent is only a job scheduler for PostgreSQL and does not translate or execute Oracle PL/SQL packages. Option C is wrong because PostgreSQL (and Cloud SQL for PostgreSQL) does not provide an Oracle compatibility mode that runs PL/SQL packages natively. Option E is wrong because the Orafce extension supplies Oracle-compatible functions and operators (e.g., NVL, DECODE, TO_DATE behaviors) but does not provide a PL/SQL package engine or convert package code.

Answer

Use pgAgent to schedule package execution.

Answer

Use Oracle compatibility mode in PostgreSQL.

Answer

Install the Orafce extension for Oracle compatibility.

Question 3

Refer to the exhibit. A developer configured a Pub/Sub push subscription to a Cloud Run service. Messages are not being delivered to the Cloud Run service. The developer verified that the service is running and the IAM permissions are correct. What is the most likely issue?

Accepted Answer

The OIDC token audience does not match the Cloud Run service's URL. For Pub/Sub push subscriptions to Cloud Run, the push endpoint must include an OIDC token whose audience matches the Cloud Run service's URL. If the audience does not match, Cloud Run rejects the request with a 401 or 403 error, and messages are not delivered. This is the most likely issue when the service is running and IAM permissions are correct.

Answer

The service account does not have the pubsub.publisher role

Answer

The push endpoint URL is not a valid HTTPS endpoint

Answer

The ackDeadlineSeconds is too short for the Cloud Run service to process messages

Question 4

A developer wants to store secrets (e.g., API keys) for use in Cloud Functions without exposing them in the source code. Which Google Cloud service should they use?

Accepted Answer

Use Secret Manager to store secrets and reference them via secret environment variables. Secret Manager is the dedicated Google Cloud service for storing sensitive data like API keys, passwords, and certificates. It provides built-in versioning, access control via IAM, and native integration with Cloud Functions through secret environment variables, ensuring secrets are never exposed in source code or configuration files.

Answer

Store secrets in a Cloud Storage bucket with encrypted objects and load them at runtime

Answer

Use Firestore to store secrets in a secure document and access it via the Firestore SDK

Answer

Use Cloud Key Management Service (Cloud KMS) to create and manage secrets

Question 5

A DevOps team is troubleshooting high latency in a Cloud Bigtable instance. They notice that the row keys are lexicographically sorted timestamps. Which TWO actions will MOST improve performance? (Select 2 answers)

Accepted Answer

Use salt (hash prefix) in the row key. Option D is correct because Bigtable stores rows in lexicographic order and distributes them across tablets by key range; timestamp-only keys cause all new writes to land on the last tablet, creating a hotspot, so adding a salt (hash prefix) spreads writes across many tablets and improves throughput/latency. Option E is correct because prepending a high-cardinality field such as user ID before the timestamp also distributes writes across the key space while still allowing efficient prefix scans per user, eliminating the sequential-write hotspot. Option A is not correct because adding nodes increases capacity but cannot fix a hot tablet caused by a monotonically increasing key, since a single tablet cannot be split to parallelize that hotspot. Option B is not correct because more column families do not change row-key distribution and can even add overhead. Option C is not correct because compression reduces storage and some I/O, but it does not address the write hotspot from lexicographically sorted timestamp keys.

Answer

Add more Bigtable nodes

Answer

Increase the number of column families

Answer

Enable compression on column families

Question 6

A company is running a global application on Cloud Spanner. They notice high write latency on a specific table because a frequently updated row is being accessed by many clients simultaneously. Which design pattern should they implement to distribute writes across multiple nodes and reduce contention?

Accepted Answer

Add a hash suffix to the primary key of the hot row to split it into multiple rows.. Adding a hash suffix to the primary key of the hot row splits the single heavily contended row into multiple logical rows, each with a different primary key. This distributes the write load across multiple Cloud Spanner splits and nodes, reducing lock contention and write latency. Cloud Spanner uses a distributed, synchronous replication architecture where a single row is managed by a single split; splitting the hot row into multiple rows allows parallel writes to different splits.

Answer

Increase the number of nodes in the Cloud Spanner instance.

Answer

Use interleaved tables to co-locate related data.

Answer

Migrate the table to Cloud Bigtable which handles hotspots better.

Question 7

A company is migrating a MySQL 5.7 database to Cloud SQL for MySQL 8.0. They use MyISAM tables and utf8 charset. What changes must they make during migration?

Accepted Answer

Convert MyISAM tables to InnoDB and change charset from utf8 to utf8mb4.. Cloud SQL for MySQL 8.0 does not support the MyISAM storage engine, so tables must be converted to InnoDB. Additionally, MySQL 8.0 defaults to utf8mb4 and deprecates the legacy utf8 (which is actually utf8mb3, limited to 3 bytes), so the charset must be migrated to utf8mb4 to support full Unicode including emoji and supplementary characters. Both changes are mandatory.

Answer

Convert MyISAM to InnoDB only; utf8 is fine in MySQL 8.0.

Answer

No changes needed; Cloud SQL automatically converts MyISAM to InnoDB and utf8 to utf8mb4.

Answer

Change charset to utf8mb4 only; MyISAM is supported in Cloud SQL.

Question 8

A company is migrating an on-premises MySQL 5.7 database to Cloud SQL for MySQL 8.0. The database includes MyISAM tables. What is the required action for these tables?

Accepted Answer

Convert MyISAM tables to InnoDB. Cloud SQL for MySQL 8.0 does not support the MyISAM storage engine; it only supports InnoDB. Therefore, before migrating, MyISAM tables must be converted to InnoDB. This conversion is required for compatibility and to leverage Cloud SQL's features such as automated backups, replication, and point-in-time recovery.

Answer

Use a MySQL 5.7 compatible Cloud SQL instance

Answer

Keep MyISAM tables as is

Answer

Migrate to Cloud Spanner instead

Question 9

Drag and drop the steps to configure a Cloud CDN with a Cloud Load Balancer in the correct order.

Accepted Answer

Create a Cloud Storage bucket, then create an external HTTP(S) load balancer with the bucket as a backend, then enable Cloud CDN on the backend bucket, then update DNS records to point to the load balancer's IP.. Cloud CDN is enabled on a backend bucket of a load balancer, then DNS is configured.

Answer

Create a Cloud Storage bucket, then enable Cloud CDN on the bucket, then create an external HTTP(S) load balancer with the bucket as a backend, then update DNS records.

Answer

Create an external HTTP(S) load balancer, then create a Cloud Storage bucket, then enable Cloud CDN on the bucket, then update DNS records.

Answer

Enable Cloud CDN on a bucket, then create an external HTTP(S) load balancer, then add the bucket as a backend, then update DNS records.

Question 10

Which three are valid ways to authenticate a service account when using the Google Cloud client libraries? (Choose three.)

Accepted Answer

Attaching a service account to a Compute Engine instance and letting the metadata server provide credentials.. Options A, B, and D are correct. These are standard methods for Application Default Credentials (ADC). Attaching a service account to a Compute Engine instance allows the metadata server to provide credentials (A). Setting the GOOGLE_APPLICATION_CREDENTIALS environment variable to point to a service account key file is another valid method (B). Using the gcloud CLI default application credentials is also a valid approach (D). Option C is incorrect because OAuth 2.0 client IDs for web applications are used for user authentication, not service account authentication. Option E is incorrect because API keys are not used for service account authentication; they are used for simple API access without a service account.

Answer

Using OAuth 2.0 client IDs for web applications.

Answer

Using an API key in the client library initialization.