Скачать или смотреть 5 Advanced SQL Interview Questions on Scalability & Hybrid Data Solutions!

🚀 Boost your SQL expertise with these advanced interview questions that dive into scalability, performance, and modern data integration!

✅ 1. Columnstore Indexes:

Columnstore indexes store data column-wise rather than row-wise, significantly improving query performance for large-scale analytics and data warehousing.

Example (SQL Server):

CREATE NONCLUSTERED COLUMNSTORE INDEX idx_ColumnStore
ON SalesOrders(OrderDate, CustomerID, TotalAmount);
Use them when performing aggregations on large datasets.

✅ 2. In-Memory OLTP in SQL Server:

In-memory OLTP leverages memory-optimized tables and natively compiled stored procedures for drastically improved transaction performance and reduced latency.

Example:

CREATE TABLE InMemoryEmployees (
EmployeeID INT NOT NULL PRIMARY KEY NONCLUSTERED,
Name NVARCHAR(100),
DepartmentID INT
) WITH (MEMORY_OPTIMIZED = ON, DURABILITY = SCHEMA_AND_DATA);
This technology is ideal for high-throughput transactional systems.

✅ 3. Distributed Transactions:

Distributed transactions span multiple databases or servers, ensuring atomicity across different systems. They typically use protocols like two-phase commit (2PC) to maintain consistency.

Concept:

When an update spans two databases, the transaction manager coordinates commits to guarantee that either both succeed or both rollback, ensuring data integrity.

✅ 4. Dynamic Management Views (DMVs):

DMVs in SQL Server provide real-time insights into system performance, resource usage, and query execution.

Example Query:

SELECT TOP 10
qs.total_elapsed_time/1000 AS TotalTime_ms,
qt.text AS QueryText,
qs.execution_count
FROM sys.dm_exec_query_stats qs
CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) qt
ORDER BY qs.total_elapsed_time DESC;
This query helps identify long-running queries and optimize performance.

✅ 5. Integrating SQL with NoSQL Systems:

Modern data architectures often combine SQL and NoSQL for a hybrid solution. Techniques include using connectors, ETL processes, or polyglot persistence, enabling SQL to query NoSQL data or vice versa.

Concept:

For example, you might use Apache Spark to join data from a SQL database with data stored in a NoSQL system like MongoDB, providing flexibility and scalability for diverse workloads.

💡 Master these advanced concepts to stand out in your next interview!

💬 Have questions or need further clarifications? Drop your queries in the comments!

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