Web Server & Database Administration Flashcards

Which Apache module provides SSL/TLS support for HTTPS connections?

Answer: mod_ssl

mod_ssl is the Apache module that implements SSL/TLS using the OpenSSL library to enable HTTPS connections.

What does the MySQL EXPLAIN statement reveal?

Answer: The query execution plan chosen by the optimizer

EXPLAIN shows how MySQL's query optimizer plans to execute a SELECT statement, including index usage and row estimates.

In PostgreSQL, what does VACUUM do?

Answer: Reclaims storage occupied by dead tuples and updates visibility maps

VACUUM reclaims space from rows deleted or updated (dead tuples) and updates the visibility map to help autovacuum and query planning.

Which Nginx directive sets the maximum allowed size of the client request body?

Answer: client_max_body_size

client_max_body_size limits the size of the request body; exceeding it returns a 413 Request Entity Too Large error.

What is the purpose of Apache's mod_proxy_fcgi module?

Answer: Forwards requests to FastCGI backends such as PHP-FPM

mod_proxy_fcgi allows Apache to forward requests to FastCGI applications (like PHP-FPM) using the FastCGI protocol.

Which command in MySQL shows all currently running queries and their status?

Answer: SHOW FULL PROCESSLIST

SHOW FULL PROCESSLIST displays all active threads in the MySQL server including query text, state, and execution time.

In Nginx, which directive configures the path to the error log and its severity level?

Answer: error_log /var/log/nginx/error.log warn

The error_log directive sets the file path and minimum severity level (debug, info, notice, warn, error, crit, alert, emerg) for Nginx error logging.