What are Foreign Data Wrappers (FDW) in PostgreSQL and what are their use cases?

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PostgreSQL Interview Questions

  1. [JUNIOR] What is PostgreSQL and how does it differ from other relational database systems?
  2. [JUNIOR] What are the key features of PostgreSQL?
  3. [JUNIOR] What are the ACID properties and how does PostgreSQL ensure them?
  4. [MID] What is MVCC (Multi-Version Concurrency Control) in PostgreSQL and why is it important?
  5. [MID] How would you optimize a slow-running query in PostgreSQL?
  6. [SENIOR] How does PostgreSQL's query planner and optimizer work and how can you influence its decisions?
  7. [JUNIOR] What is the difference between a primary key and a unique constraint in PostgreSQL?
  8. [JUNIOR] What is a foreign key in PostgreSQL and how is it used to enforce referential integrity?
  9. [JUNIOR] What are the different data types available in PostgreSQL?
  10. [JUNIOR] How do you create a new database and table in PostgreSQL?
  11. [MID] What is the EXPLAIN command and how do you use EXPLAIN ANALYZE for query tuning?
  12. [MID] What are the different types of indexes available in PostgreSQL and when would you use each?
  13. [MID] What is the VACUUM command and why is vacuuming necessary in PostgreSQL?
  14. [MID] What is a materialized view and how does it differ from a regular view?
  15. [SENIOR] How does WAL (Write-Ahead Logging) work in PostgreSQL and why is it critical for data integrity?
  16. [SENIOR] How would you configure and troubleshoot streaming replication in PostgreSQL?
  17. [SENIOR] How do you identify and resolve performance bottlenecks using pg_stat_statements and pg_stat_activity?
  18. [JUNIOR] What is the difference between TRUNCATE and DELETE commands in PostgreSQL?
  19. [JUNIOR] What are the different types of JOINs in PostgreSQL and when would you use each?
  20. [JUNIOR] What is a view in PostgreSQL and how do you create one?
  21. [JUNIOR] How do you create an index in PostgreSQL and why are indexes important?
  22. [JUNIOR] What is the difference between INNER JOIN and LEFT JOIN in PostgreSQL?
  23. [MID] What are CTEs (Common Table Expressions) in PostgreSQL and when should you use them?
  24. [MID] What are window functions in PostgreSQL and how are they used?
  25. [MID] How do you handle JSON and JSONB data in PostgreSQL and what are the differences between them?
  26. [MID] What are triggers in PostgreSQL and how do you create them?
  27. [MID] How do you perform backup and restore in PostgreSQL using pg_dump and pg_restore?
  28. [MID] What is the difference between synchronous and asynchronous replication in PostgreSQL?
  29. [SENIOR] How do you handle deadlocks in PostgreSQL and what strategies prevent them?
  30. [SENIOR] What are the different backup strategies in PostgreSQL and when would you use each?
  31. [SENIOR] How would you design a partitioning strategy for a table with billions of rows?
  32. [SENIOR] What is the role of the pg_stat_replication view and how do you monitor replication lag?
  33. [SENIOR] How would you implement row-level security in PostgreSQL?
  34. [EXPERT] How would you implement sharding in PostgreSQL and what are the trade-offs compared to partitioning?
  35. [JUNIOR] What is a schema in PostgreSQL and why are schemas useful?
  36. [JUNIOR] What is a transaction in PostgreSQL and how do you control transactions?
  37. [JUNIOR] How do you grant and revoke user permissions in PostgreSQL?
  38. [JUNIOR] What is the SERIAL data type and how is it used for auto-incrementing columns?
  39. [MID] What is the pg_hba.conf file and what is its purpose?
  40. [MID] How do you implement partitioning in PostgreSQL and when is it beneficial?
  41. [MID] What are stored procedures and functions in PostgreSQL and how do they differ?
  42. [MID] How does PostgreSQL handle concurrent transactions and what are the transaction isolation levels?
  43. [MID] What are sequences in PostgreSQL and how are they used?
  44. [MID] How do you implement full-text search in PostgreSQL?
  45. [SENIOR] How do you implement logical replication and what are its advantages over physical replication?
  46. [SENIOR] What are GIN and GiST indexes and when would you choose one over the other?
  47. [SENIOR] How would you migrate a large PostgreSQL database to a new server with minimal downtime?
  48. [SENIOR] How do you implement parallel query execution in PostgreSQL and when is it most beneficial?
  49. [SENIOR] How would you design a database schema to support multi-tenancy in PostgreSQL?
  50. [EXPERT] How does PostgreSQL's MVCC implementation handle transaction ID wraparound and what are the implications for long-running systems?
  51. [EXPERT] How would you design a disaster recovery strategy for PostgreSQL with near-zero RPO and minimal RTO?
  52. [JUNIOR] What is normalization and what are the different normal forms?
  53. [JUNIOR] What are constraints in PostgreSQL and what types are available?
  54. [JUNIOR] What is the difference between UNION and UNION ALL in PostgreSQL?
  55. [MID] What is the difference between a CTE and a subquery in terms of performance and readability?
  56. [MID] How do you handle exceptions in PL/pgSQL?
  57. [MID] What are PostgreSQL extensions and what are some commonly used ones?
  58. [MID] How does indexing affect insert and update performance in PostgreSQL?
  59. [MID] What is the difference between VACUUM and VACUUM FULL in PostgreSQL?
  60. [MID] How would you perform a bulk data insertion in PostgreSQL while minimizing performance impact?
  61. [SENIOR] What are Foreign Data Wrappers (FDW) in PostgreSQL and what are their use cases?
  62. [SENIOR] How do you implement data encryption at rest and in transit in PostgreSQL?
  63. [SENIOR] What is a partial index and when would you use one over a regular index?
  64. [SENIOR] How does PostgreSQL handle index-only scans and when are they beneficial?
  65. [EXPERT] How does the PostgreSQL buffer manager and shared buffer pool work and how do you tune it for high-throughput workloads?
  66. [EXPERT] How would you implement a custom PostgreSQL extension or plugin?
  67. [EXPERT] What are the internals of the PostgreSQL WAL and how does checkpoint tuning affect performance?
  68. [JUNIOR] What is pgAdmin and what purpose does it serve in PostgreSQL administration?
  69. [JUNIOR] How do you insert, update, and delete data in a PostgreSQL table?
  70. [MID] What is the concept of table inheritance in PostgreSQL and what are its use cases?
  71. [MID] What is the hstore data type and when would you use it?
  72. [MID] What are the differences between temporary tables and unlogged tables in PostgreSQL?
  73. [SENIOR] What are covering indexes in PostgreSQL and how can they improve query performance?
  74. [SENIOR] How do you use the pg_stat_activity view to monitor and troubleshoot active sessions?
  75. [SENIOR] What is the process for recovering from a crash in PostgreSQL?
  76. [EXPERT] How does PostgreSQL's cost-based optimizer estimate row counts and join costs and what happens when statistics are stale?
  77. [EXPERT] How would you design and implement a zero-downtime schema migration strategy for a high-traffic PostgreSQL database?
  78. [EXPERT] How does connection pooling with PgBouncer or Pgpool-II work and what are the performance implications of different pooling modes?
  79. [JUNIOR] What are the different operators available in PostgreSQL?
  80. [MID] What are the differences between SERIAL and BIGSERIAL data types?
  81. [MID] What is a tablespace in PostgreSQL and when would you use one?
  82. [SENIOR] How do you approach index maintenance and reindexing strategies in PostgreSQL?
  83. [EXPERT] What are the considerations for implementing PostgreSQL on Kubernetes with persistent storage and high availability?
  84. [EXPERT] How do you implement Event-Driven Architecture patterns using PostgreSQL LISTEN/NOTIFY?
  85. [EXPERT] How do callback functions work in PostgreSQL's internal architecture?