Sample Exam Questions

From the objective of OSS-DB Exam Silver
- Operation and Management - configuration file (postgresql.conf)

Sample Question


Regarding postgresql.conf, choose the most appropriate description.

  1. After modifying the file, many parameters are reflected by execution of pg_ctl reload, but some of the parameters are effective immediately by file modification.
  2. Multiple parameters can be set on a single line by separating them with a semicolon (;). 
  3. When you end the line with a backslash (\), it becomes a continuation line, and parameters can be set across multiple lines.
  4. You can place # at the beginning of a line to make that line a comment line, or you can put # in the middle of a line and make a description on the right side of it as a comment.
  5. By executing ALTER SYSTEM, the contents are rewritten.

※This sample exam is different from those that appear in the actual OSS-DB Exam.

Answer and Explanation

postgresql.conf file contains  a variety of settings for the PostgreSQL database cluster. After changing the configuration file, there are parameters that become effective by reloading the file and parameters that require restarting the database.

The former, for example pg_ctl reload, the latter is enabled by, for example, pg_ctl restart. 

Parameters can be only one set per line. 

# is a symbol that is used to comment, than the right-hand side it becomes a comment. If you put the beginning of the line, the entire line is a comment line. 

But from version 9.4 ALTER SYSTEM command has been added, change of this is written to a file called, set the contents of the takes precedence over postgresql.conf. 

Therefore, the correct answer is D.