Postgres Quiz Archive

You have 200 seconds to answer 20 Random questions so think fast!

You will need to score 80% or over to pass!

Created by

Paul Sammy

PostgreSQL 14 Internals Chapter 1

A quiz to test the knowledge of those reading and learning from Postgres 14 Internals book by Egor Rogov, covering topics in Chapter 1.

1 / 20

1. To understand each other, a client and a server must use one and the same interfacing protocol?

True

False

2 / 20

2. What is the purpose of the public schema?

no such schema

restricted schema for postgres internal usage only

default schema for user objects

schema used for heterogeneous replication

3 / 20

3. System Catalog tables begin with which prefix?

dba_

pg_

sys_

cat_

4 / 20

4. If we create a new tablespace which directory will symbolic links be created from?

pg_tablespace

pg_symlinks

pg_tabspace

pg_tblspc

5 / 20

5. Each tablespaces can only be assigned for use by one database

True

False

6 / 20

6. Postgres by default has built in connection pooling abilities?

True

False

7 / 20

7. When PostgreSQL is running what can it be referred to as?

Choose 2 option

Aurora

Quorum

Instance

Postgres Server

8 / 20

8. What is the purpose of wal writer?

collects usage statistics for the instance.

flushes dirty pages to disk.

executes checkpoints

writes WAL entries to disk

9 / 20

9. TOAST tables reside in a seperate schema?

True

False

10 / 20

10. What is the name of the 2 default tablespaces created after initialization?

choose 2

pg_global

pg_tablespace

pg_temp

pg_default

11 / 20

11. Which of below are predefined schemas?

choose 2

pg_catalog

public

system

postgres

12 / 20

12. How many files or forks on disk will a 10Mb table with no index have?

13 / 20

13. The default Page size is 2k?

False

True

14 / 20

14. Each Database has its own System Catalog?

False

True

15 / 20

15. Which fork is specific for unlogged tables?

Main fork

Initialization fork

free space map

visiblilty map

16 / 20

16. What 3 files/forks as a minimum make up a table on disk?

Main fork

visiblilty map

free space map

table map

17 / 20

17. What is the purpose of autovacuum?

Removes stale data from tables and indexes

Rebuilds indexes with b level greater than 2

Performs a backup of WAL logs

Deletes old logs and traces on disk

18 / 20

18. Postgres uses a thread based process model?

True

False

19 / 20

19. Files are logically split into pages?

True

False

20 / 20

20. What column in system catalogs servers as the Primary Key

obj

oid

obj#

oid#

Your score is

Created by

Paul Sammy

PostgreSQL 14 Internals Chapter 2

A quiz to test the knowledge of those reading and learning from Postgres 14 Internals book by Egor Rogov, covering topics in Chapter 2.

1 / 10

1. Which of the below are valid Isolations Levels?

choose 2

Random Scatter

Read Committed

Serializable

Rollback Read

2 / 10

2. What is the default Isolation Level?

Read Uncommitted

Serializable

Repeatable Read

Read Committed

3 / 10

3. non-repeatable read anomaly occurs when?

A transaction reads one and the same row once and modifies this row and commits the change.

A transaction reads one and the same row twice, another transaction modifies this row between these reads and commits the change.

A transaction reads one and the same row twice, another transaction modifies this row between these reads issue a rollback.

A transaction reads one and the same row once, another transaction modifies this row between these reads and commits the change.

4 / 10

4. A phantom read anomaly occurs when?

The same transactions issues a commit, then a rollback to restore data to its original value

The same transaction executes two identical queries returning a set of rows that satisfy a particular condition, while another transaction also queries this same data.

The same transaction executes two identical queries returning a set of rows that satisfy a particular condition, while another transaction adds some other rows satisfying this condition and commits.

A transactions inserts a null value into a not null columns and commits

5 / 10

5. Lost updates are forbidden by the standard at all isolation levels?

True

False

6 / 10

6. What are some of database features we can use to avoid a non repeatable read?

Select more than 1 answer below:

Replace procedural code with declarative one.

Issues a rollback after the commit to satisfy repeatable read.

Apply explicit locks

Use a single SQL operator

7 / 10

7. Which of the below would best describe a dirty read?

reading data direct from memory using pg_dirt

a session being able to see commited data altered by another session

reading the data directly from file using a text editor such as vi or notepad

a session being able to see uncommited data altered by another session

8 / 10

8. which of the below statements will start a transaction as Read Repeatable?

BEGIN ISOLATION LEVEL REPEATABLE READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

CREATE EXTENSTION REPEATABLE_READ;

SET ISO=REPEATABLE_READ;

9 / 10

9. Which parameters sets the database default isolation level?

default_transaction_isolation

transaction_isolation_level

default_isolation_level

active_transaction_isolation

10 / 10

10. At any moment the database system can contain several versions of one and the same row?

False

True

Your score is

Created by

Paul Sammy

PostgreSQL 14 Internals Chapter 3

A quiz to test the knowledge of those reading and learning from Postgres 14 Internals book by Egor Rogov, covering topics in Chapter 3.

1 / 10

1. To identify different versions of one and the same row, PostgreSQL marks each of them with which two value?

xmin

xmas

xmax

xid

2 / 10

2. index row headers like table row headers contain xmin and xmax fields?

True

False

3 / 10

3. at any one time Postgres can have several versions of a row?

False

True

4 / 10

4. a transaction containing a savepoint is will still be considered as only a single transaction?

True

False

5 / 10

5. Rows of TOAST tables are handled in such a way that they are never update?

True

False

6 / 10

6. Page free space can often become fragmented?

False

True

7 / 10

7. Which 2 items does a Virtual XID consist of?

xmin

sequential number

checksum

backend process ID

8 / 10

8. What does an Item Pointer contain?

choose 3

tuple xid

tuple status

tuple offset from the start of the page

tuple length

9 / 10

9. The page Special Space is located at the start of the page with highest address

False

True

10 / 10

10. CLOG contains how many bits for each transaction?

Your score is

Cookie	Duration	Description
cookielawinfo-checkbox-analytics	11 months	This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Analytics".
cookielawinfo-checkbox-functional	11 months	The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional".
cookielawinfo-checkbox-necessary	11 months	This cookie is set by GDPR Cookie Consent plugin. The cookies is used to store the user consent for the cookies in the category "Necessary".
cookielawinfo-checkbox-others	11 months	This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Other.
cookielawinfo-checkbox-performance	11 months	This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Performance".
viewed_cookie_policy	11 months	The cookie is set by the GDPR Cookie Consent plugin and is used to store whether or not user has consented to the use of cookies. It does not store any personal data.