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

choose 2

pg_global

pg_default

pg_tablespace

pg_temp

2 / 20

2. What command is used to create the Postgres cluster?

Initialize

StartNewPG

CreateCluster

CreatePGC

3 / 20

3. To be able to restore data consistency, Postgres maintains

rollback segments (RBS)

undo segments (UNDO)

online redo logs (ORL)

write-ahead log (WAL)

4 / 20

4. How does Postgres know which schema to use if not specified?

Directory Path

Search Path

Access Path

Schema Path

5 / 20

5. Which of the below objects can be referred to as relations?

choose 3

sequences

indexes

tables

triggers

6 / 20

6. What is the purpose of autovacuum?

Performs a backup of WAL logs

Removes stale data from tables and indexes

Rebuilds indexes with b level greater than 2

Deletes old logs and traces on disk

7 / 20

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

free space map

visiblilty map

Main fork

table map

8 / 20

8. Which of below are predefined schemas?

choose 3

pg_schema

pg_temp

information_schema

pg_toast

9 / 20

9. The information_schema schema provides information on Postgres release notes?

True

False

10 / 20

10. A single Postgres Instance can server only one database?

True

False

11 / 20

11. The pg_default tablespace should never be used to create user tables?

True

False

12 / 20

12. Users should not modify the template0 database

True

False

13 / 20

13. It is the postmasters job to listener for incoming connections?

False

True

14 / 20

14. Files are logically split into pages?

False

True

15 / 20

15. System Catalog tables begin with which prefix?

cat_

sys_

pg_

dba_

16 / 20

16. How many rows in a page does Postgres aim to have before considering TOAST?

17 / 20

17. Which fork keeps track of available space within pages?

used space map

wal space map

vacuum space map

free space map

18 / 20

18. The default Page size is 2k?

True

False

19 / 20

19. What is the default standard size for a fork file?

5GB

1MB

5MB

1GB

20 / 20

20. Some System Catalog tables are common to all databases in the cluster?

False

True

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 parameters sets the database default isolation level?

active_transaction_isolation

default_transaction_isolation

default_isolation_level

transaction_isolation_level

2 / 10

2. non-repeatable read anomaly occurs when?

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 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 issue a rollback.

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

3 / 10

3. What is the default Isolation Level?

Repeatable Read

Read Committed

Read Uncommitted

Serializable

4 / 10

4. Which of the below are valid Isolations Levels?

choose 2

Read Committed

Serializable

Rollback Read

Random Scatter

5 / 10

5. Snapshot isolation is preferred but increases the number of required locks?

False

True

6 / 10

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

True

False

7 / 10

7. The SQL standard specifies three isolation levels?

False

True

8 / 10

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

Select more than 1 answer below:

Use a single SQL operator

Apply explicit locks

Issues a rollback after the commit to satisfy repeatable read.

Replace procedural code with declarative one.

9 / 10

9. Data Consistency is best handled at the application layer rather than at the database layer?

True

False

10 / 10

10. A phantom read anomaly occurs when?

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

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.

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.

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. Each page has a layer that usually consists of?

choose 2

undo segment

free space

page header

flashback block

2 / 10

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

xmin

backend process ID

sequential number

checksum

3 / 10

3. Tuples can also be referred to as columns?

True

False

4 / 10

4. Information about subtransactions is stored under?

PGDATA/pg_xid

PGDATA/pg_subtrans

PGDATA/subtrans

PGDATA/pg_min

5 / 10

5. CLOG contains how many bits for each transaction?

6 / 10

6. indexes do not use row versioning?

False

True

7 / 10

7. When a row is created, its xmin value is set to the transaction ID of which command?

INSERT

COMMIT

CREATE

DELETE

8 / 10

8. Page free space can often become fragmented?

False

True

9 / 10

9. Page header sizes can be easily displayed using the <choose from answers> extension

pageheadinfo

pagedetect

pagesize

pageinspect

10 / 10

10. CLOG Pages are never cached in memory?

False

True

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.