IBM A1000-051 Advanced Practice Exam: Hard Questions 2025

An enterprise runs IBM InfoSphere BigInsights on a shared Hadoop cluster. Data scientists complain that SQL queries in Big SQL intermittently fail with timeouts during peak ETL windows, while MapReduce and Spark jobs continue to run. Cluster metrics show YARN is healthy, but Big SQL query fragments stall and then cancel. Which architecture-level change most directly addresses the root cause while preserving multi-tenant isolation?

A BigInsights cluster uses HDFS Transparent Encryption (TDE) for a regulatory dataset. A new ingestion pipeline writes encrypted files successfully, but downstream Big SQL queries on those tables fail with permission errors when run by analysts who have HDFS read permissions. Hive/HCatalog metadata is correct. What is the most likely missing configuration to enable authorized users to read encrypted data via Big SQL?

A team runs a nightly workflow: ingest JSON -> stage raw -> transform to ORC -> serve via Big SQL. They observe that Big SQL performance degrades over weeks even though data volume increases only modestly. Investigation shows the ORC tables have an exploding number of small files and highly fragmented partitions. Which remediation provides the best long-term fix with minimal disruption to upstream ingestion?

A cluster uses Kerberos and Apache Ranger for HDFS and Hive/HCatalog authorization. Users can query tables in Hive, but Big SQL users intermittently see 'permission denied' errors when accessing the same data, especially right after policy updates. The Ranger Admin is healthy. What is the most probable cause and best corrective action?

A BigInsights environment must support both ad-hoc analytics (low latency) and heavy batch ETL (high throughput). During month-end, ad-hoc users complain that interactive queries become unusable. The cluster cannot be expanded immediately. Which design provides the best balance using existing resources while maintaining predictable SLAs?

A Spark job reading from HDFS and writing curated ORC data intermittently fails with executor OOM errors. The job processes a skewed key distribution; one partition contains far more records than others. Increasing executor memory helps temporarily but failures recur as data grows. What is the best long-term fix that addresses the root cause?

A security team requires that only masked values of PII columns are exposed to analysts, while a small compliance group can view full values. The same Hive/HCatalog tables are accessed by Big SQL and other engines. Which approach best satisfies centralized governance and consistent enforcement across access paths?

After a planned maintenance window, multiple services come up, but HDFS appears healthy while Hive Metastore-dependent tools (including Big SQL catalog operations) fail intermittently. Logs show timeouts and occasional 'too many connections' errors to the metastore database. What is the most likely root cause and the best remediation?

A BigInsights cluster experiences periodic performance cliffs: HDFS throughput drops and many tasks slow down simultaneously, but disk and network are not saturated. Investigations show frequent long JVM pauses on DataNodes and the NameNode during these events. Which action is most appropriate to mitigate the issue while keeping the system stable?

A team wants to accelerate Big SQL queries on a large fact table partitioned by date. Queries typically filter on date ranges and a few dimensions, but performance is inconsistent: some queries prune partitions correctly, others scan far more data than expected. The SQL is generated by a BI tool and often wraps predicates in functions (for example, applying DATE() or CAST() on the partition column). What is the best recommendation to stabilize partition pruning without changing the underlying data layout?