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 a schema?

A memory area used to cache data from LRU chains

The name used to refer to a super user account

This is the same as a user in Postgres

Namespace that store all objects of a database

2 / 20

2. What is the process first launched at server start?

pginit

init

postman

postgres

3 / 20

3. What is the name of the directory that contains the files related to the Postgres cluster?

PGCORE

PGDATA

PGTIPS

PGBASE

4 / 20

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

pg_tabspace

pg_tblspc

pg_tablespace

pg_symlinks

5 / 20

5. Which of below are predefined schemas?

choose 3

information_schema

pg_toast

pg_temp

pg_schema

6 / 20

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

choose 3

indexes

sequences

triggers

tables

7 / 20

7. Tablespaces can be used to segregate data based on performance needs?

False

True

8 / 20

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

9 / 20

9. Which fork contains the actual table data?

table map

Main fork

visiblilty map

free space map

10 / 20

10. What is another name for the postgres process?

masterprocess

postmaster

postmanager

aurora

11 / 20

11. What is the purpose of wal writer?

executes checkpoints

writes WAL entries to disk

collects usage statistics for the instance.

flushes dirty pages to disk.

12 / 20

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

rollback segments (RBS)

write-ahead log (WAL)

online redo logs (ORL)

undo segments (UNDO)

13 / 20

13. Which fork is specific for unlogged tables?

Main fork

visiblilty map

Initialization fork

free space map

14 / 20

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

True

False

15 / 20

15. What is the purpose of the template0 database?

No such database

Useful for Postgres support Services to debug issues

Useful for creating development schemas

Useful for restoring data from a logical backup or creating a database with a different encoding

16 / 20

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

choose 2

pg_temp

pg_default

pg_tablespace

pg_global

17 / 20

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

vacuum space map

free space map

used space map

wal space map

18 / 20

18. Files are logically split into pages?

True

False

19 / 20

19. What is the name of the mechanism used to store a row bigger than a page size?

TOAST

BAKE

GROW

BREAD

20 / 20

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

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

False

True

2 / 10

2. The SQL standard specifies three isolation levels?

False

True

3 / 10

3. 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, 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.

4 / 10

4. What is the default Isolation Level?

Serializable

Read Committed

Read Uncommitted

Repeatable Read

5 / 10

5. Which isolation level in theory could mean an application does not have to consider isolation anomalies?

Repeatable Read

Serializable

Read Committed

Read Uncommitted

6 / 10

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

BEGIN ISOLATION LEVEL REPEATABLE READ;

SET ISO=REPEATABLE_READ;

CREATE EXTENSTION REPEATABLE_READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

7 / 10

7. 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

8 / 10

8. Which parameters sets the database default isolation level?

active_transaction_isolation

default_isolation_level

transaction_isolation_level

default_transaction_isolation

9 / 10

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

Select more than 1 answer below:

Apply explicit locks

Use a single SQL operator

Replace procedural code with declarative one.

Issues a rollback after the commit to satisfy repeatable read.

10 / 10

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

True

False

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. The page header stores checksum and the sizes of the other parts of the page?

True

False

2 / 10

2. Postgres table physical data files are always cross compatible across platforms?

True

False

3 / 10

3. indexes do not use row versioning?

True

False

4 / 10

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

COMMIT

CREATE

DELETE

INSERT

5 / 10

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

False

True

6 / 10

6. virtual IDs exist only in PGDATA/pg_vxid when not cached?

True

False

7 / 10

7. The page header is located in the highest address?

True

False

8 / 10

8. status of a subtransaction is written into CLOG?

True

False

9 / 10

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

backend process ID

checksum

xmin

sequential number

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.