PCDE Practice Test 32 — 15 Questions

Question 1

You have a Memorystore for Redis instance that serves as a session store for a web application. The instance is running low on memory and is approaching the maxmemory limit. You want to ensure that the least recently used keys are evicted first when memory is full. Which eviction policy should you configure?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

volatile-lru. The volatile-lru policy evicts keys with an expire set (TTL) using the LRU algorithm. For a session store, sessions typically have a TTL, so volatile-lru is appropriate. allkeys-lru would evict any key regardless of TTL, which might remove important keys. noeviction would cause write errors when memory is full. volatile-ttl evicts based on TTL, not LRU.

Answer

allkeys-lru

Answer

noeviction

Answer

volatile-ttl

Question 2

A company is using Cloud SQL for MySQL and wants to perform disaster recovery testing by promoting a read replica to a standalone instance. Which TWO actions are required? (Choose 2)

Accepted Answer

Stop replication on the replica using the Cloud Console or gcloud.. To promote a read replica to a standalone instance, you must stop replication on the replica and then promote it. The promotion process converts the replica into an independent primary instance.

Answer

Delete the replica and recreate it as a primary instance.

Answer

Enable point-in-time recovery on the replica.

Answer

Disable binary logging on the replica.

Question 3

You are responsible for a Cloud Spanner instance that serves a global user base. A new feature requires adding an index on a column of an existing table that contains millions of rows. The table is actively used by production traffic. What is the recommended approach to add the index with minimal impact?

Accepted Answer

Use the gcloud command 'gcloud spanner databases ddl update' with a CREATE INDEX statement. The operation will be non-blocking and will not impact production traffic.. Cloud Spanner supports online, non-blocking index creation. The CREATE INDEX statement processes the index in the background and does not block reads or writes on the table. This is the most efficient and least impactful method. Using a backup/restore or export/import is unnecessarily complex and disruptive.

Answer

Create a second table with the index already defined, then copy the data using batch writes and switch traffic. This avoids any impact to the original table.

Answer

Take a full database backup to Cloud Storage, restore it to a new instance, create the index on the restored instance, and then fail over to the new instance.

Answer

Use the gcloud command 'gcloud spanner databases ddl update' with an ALTER TABLE statement to add the index. This will lock the table briefly but is acceptable.

Question 4

A team wants to implement policy-as-code to check Terraform plans for compliance before deployment. They prefer an open-source tool that works with any CI/CD pipeline and can evaluate policies expressed in Rego. Which tool should they use?

Accepted Answer

Conftest. Conftest is a CLI tool that uses OPA/Rego to evaluate configuration files and Terraform plans. It is open-source and can be integrated into CI/CD. Sentinel is proprietary to Terraform Cloud. Cloud Build is not a policy engine.

Answer

Cloud Deployment Manager

Answer

Sentinel

Answer

Cloud Build

Question 5

A Cloud SQL for PostgreSQL instance is experiencing a surge in read traffic. The team wants to offload read queries without affecting write latency. What should they do?

Accepted Answer

Create a same-region read replica. Creating read replicas allows distributing read traffic, reducing load on the primary instance for writes. Read replicas are the standard solution for scaling read workloads.

Answer

Enable automated backups

Answer

Create a cross-region read replica

Answer

Increase the CPU of the primary instance

Question 6

You need to set up disaster recovery for a Cloud SQL for PostgreSQL instance. The primary instance is in us-central1, and you want a standby in us-west1 that can be promoted to a standalone instance during a regional outage. The solution must minimize data loss and recovery time. Which approach should you take?

Accepted Answer

Create a cross-region read replica in us-west1. During a disaster, promote the replica to a standalone instance.. Cross-region read replicas in Cloud SQL for PostgreSQL use synchronous replication (for regional replicas, it's asynchronous across regions, but still the best option for DR). Creating a cross-region read replica in us-west1 allows it to be promoted to a standalone instance in DR scenarios. Cross-region backups are point-in-time backups, not a live standby. External replication is not managed by Cloud SQL.

Answer

Configure cross-region automated backups with a retention of 7 days. In the event of a disaster, restore the latest backup to a new instance in us-west1.

Answer

Set up an on-premise PostgreSQL instance and configure streaming replication from Cloud SQL to the on-premise instance.

Answer

Use gcloud sql instances create with a backup configuration pointing to us-west1, but this does not create a live standby.

Question 7

A Cloud SQL for MySQL instance is running low on disk space. You have enabled automatic storage increase, but you also want to be proactively alerted when disk usage exceeds 80%. Which steps should you take?

Accepted Answer

Create a Cloud Monitoring alert on the metric 'disk/utilization' with a threshold of 80%.. Cloud Monitoring allows you to create alerting policies based on metrics. The disk usage metric for Cloud SQL is available, and you can set a threshold of 80%. Automatic storage increase is a separate setting that automatically increases storage when needed.

Answer

Set the storage size to a fixed large value to avoid alerts.

Answer

Create a Cloud Logging sink for disk usage logs and set up a Pub/Sub notification.

Answer

Use Cloud SQL's built-in email notifications for disk usage.

Question 8

A company is using Cloud Spanner and wants to back up a database to Cloud Storage for long-term retention. They also need to restore the database to a specific point in time within the last 7 days. Which two features should they use? (Choose TWO.)

Accepted Answer

Use Spanner's point-in-time recovery feature to restore to a specific timestamp. Spanner supports creating backups and restoring from them. Backups can be stored in Cloud Storage (as part of the backup process) and can be used for point-in-time recovery within a configurable retention period (up to 7 days by default).

Answer

Set up a cross-region replica for backup

Answer

Enable version management on the Spanner instance

Answer

Export the database using gcloud spanner databases export

Question 9

A data team is migrating an Oracle database to Cloud SQL for PostgreSQL. They have used Ora2Pg to convert the schema. After conversion, they notice several issues with data type mappings. Which THREE Oracle-to-PostgreSQL mappings are correct? (Choose 3)

Accepted Answer

NUMBER(10,2) -> NUMERIC(10,2). NUMBER(10) -> INTEGER, NUMBER(10,2) -> NUMERIC(10,2), DATE -> TIMESTAMP are correct. CLOB -> TEXT is also correct but only three needed.

Answer

VARCHAR2(10) -> TEXT

Answer

DATE -> DATE

Question 10

A team is migrating a MySQL database to Cloud SQL using DMS. They need to configure the source database for binary logging. Which TWO parameters must be set correctly?

Accepted Answer

binlog_format = ROW. For MySQL binary logging to work with DMS, log_bin must be ON and binlog_format must be ROW (or MIXED). ROW-level logging ensures all changes are captured.

Answer

expire_logs_days = 0

Answer

binlog_format = STATEMENT

Answer

server_id = 1

Question 11

A company is migrating a 10 TB Teradata data warehouse to BigQuery. They need to convert Teradata DDL and BTEQ scripts to BigQuery SQL. Which Google Cloud service should they use?

Accepted Answer

Schema Conversion Tool (SCTS). Schema Conversion Tool (SCTS) is designed to convert DDL and SQL scripts from sources like Teradata to BigQuery-compatible format.

Answer

BigQuery Data Transfer Service

Answer

Database Migration Service (DMS)

Answer

gcloud bigquery load

Question 12

A company uses Cloud Bigtable for real-time analytics. They need to implement disaster recovery across regions with a recovery point objective (RPO) of no more than 5 minutes and recovery time objective (RTO) under 10 minutes. Which approach should they take?

Accepted Answer

Configure Bigtable replication with a secondary cluster in a different region and use Cloud DNS health checks to update routing policy on failover.. Bigtable replication allows creating secondary clusters in different regions. Asynchronous replication has typical lag of a few seconds to minutes, meeting RPO of 5 minutes. For failover, the application's routing policy must be updated to point to the secondary cluster. Cloud DNS health checks can detect primary failure and automatically update routing policy. Backups have RPO equal to backup interval (hours) and RTO of hours. Exporting to Cloud Storage is manual and slow. Using Cloud Spanner is a different service.

Answer

Perform daily exports of Bigtable data to Cloud Storage and import into a new cluster in case of failure.

Answer

Migrate the workload to Cloud Spanner multi-region for built-in disaster recovery.

Answer

Use Cloud Scheduler to trigger a script that takes a Bigtable snapshot every hour.

Question 13

A company uses Cloud Spanner multi-region with the nam-eur-asia1 configuration. They experience a regional outage that affects two of the three regions. What is the expected behavior regarding read and write availability?

Accepted Answer

Read and write availability are unaffected because Spanner automatically fails over to remaining regions.. Spanner multi-region with 5+ regions (like nam-eur-asia1 which has 3 regions with multiple zones each) can tolerate the loss of up to two regions while maintaining read/write availability. The remaining region(s) will continue to serve reads and writes. However, if the leader region is lost, a new leader is elected from remaining regions, which may cause a brief write unavailability (RTO <1 min). Spanner guarantees 99.999% availability for multi-region instances.

Answer

Reads are available but writes are unavailable until the leader region recovers.

Answer

The entire instance becomes unavailable due to loss of quorum.

Answer

The instance becomes read-only until at least two regions recover.

Question 14

A company is migrating a MySQL database to Cloud SQL using Database Migration Service (DMS). The source database is on-premises with a public IP address. Which networking configuration is required on the source to allow DMS to connect?

Accepted Answer

Allowlist the DMS public IP addresses in the source database firewall.. For DMS to connect to a source with a public IP, the source must allowlist the IP addresses of the DMS instance to bypass firewall restrictions.

Answer

Create a VPC peering connection between the source and DMS.

Answer

Install the Cloud SQL Auth Proxy on the source database.

Answer

Configure a Cloud VPN tunnel between the on-premises network and Google Cloud.

Question 15

A financial services company runs a global trading application on Cloud Spanner. They need the highest availability with 99.999% SLA and automatic failover with zero data loss. Which Spanner configuration should they choose?

Accepted Answer

Multi-region configuration nam-eur-asia1 (US, Europe, Asia). Multi-region configurations provide 99.999% SLA. Among the options, nam-eur-asia1 spans three continents with read-write replicas in each continent, offering automatic failover with zero data loss (RPO=0). Regional configuration offers 99.99% SLA. Multi-region with only read-only replicas in some regions does not achieve the same failover capability.

Answer

Regional configuration in us-central1 with read replicas

Answer

Multi-region configuration nam6 (US, limited to North America)

Answer

Regional configuration with a cross-region standby using backup/restore