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_tablespace

pg_default

pg_global

pg_temp

2 / 20

2. What is the purpose of wal writer?

executes checkpoints

flushes dirty pages to disk.

writes WAL entries to disk

collects usage statistics for the instance.

3 / 20

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

False

True

4 / 20

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

False

True

5 / 20

5. System Catalog tables begin with which prefix?

pg_

sys_

dba_

cat_

6 / 20

6. Each Database has its own System Catalog?

False

True

7 / 20

7. Who is the Author of the Postgres 14 Internals book?

Dan Brown

Egor Rogov

Sam Altman

Paul Sammy

8 / 20

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

False

True

9 / 20

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

BAKE

BREAD

TOAST

GROW

10 / 20

10. Files are logically split into pages?

False

True

11 / 20

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

rollback segments (RBS)

write-ahead log (WAL)

undo segments (UNDO)

online redo logs (ORL)

12 / 20

12. What is the purpose of the template1 database?

No such database

a template for all the other databases

database used for temporary tables

regular database that you can use at your discretion

13 / 20

13. Tablespaces are used to define physical data layout?

False

True

14 / 20

14. What is the point of the pg_global tablespace?

stores WAL logs used for global replication

stores system catalog objects that are common to the whole cluster

stores temporary tables that are common to the whole cluster

stores user tables that are common to the whole cluster

15 / 20

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

Main fork

table map

free space map

visiblilty map

16 / 20

16. What is the purpose of autovacuum?

Rebuilds indexes with b level greater than 2

Removes stale data from tables and indexes

Deletes old logs and traces on disk

Performs a backup of WAL logs

17 / 20

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

True

False

18 / 20

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

pginit

init

postgres

postman

19 / 20

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

oid

oid#

obj

obj#

20 / 20

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

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. 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 issue a rollback.

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

2 / 10

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

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

reading data direct from memory using pg_dirt

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

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

3 / 10

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

True

False

4 / 10

4. What is the acronym used for the attributes that ensure Data consistency, integrity and durability?

SOC2

ACID

SAFE

HIPPA

5 / 10

5. Which of the below are valid Isolations Levels?

choose 2

Read Committed

Rollback Read

Serializable

Random Scatter

6 / 10

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

SET ISO=REPEATABLE_READ;

CREATE EXTENSTION REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

7 / 10

7. 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 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.

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

8 / 10

8. What is the default Isolation Level?

Serializable

Read Uncommitted

Repeatable Read

Read Committed

9 / 10

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

False

True

10 / 10

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

Read Uncommitted

Repeatable Read

Read Committed

Serializable

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. Which 2 items does a Virtual XID consist of?

backend process ID

xmin

sequential number

checksum

2 / 10

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

False

True

3 / 10

3. What does an Item Pointer contain?

choose 3

tuple status

tuple offset from the start of the page

tuple length

tuple xid

4 / 10

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

pageinspect

pageheadinfo

pagedetect

pagesize

5 / 10

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

True

False

6 / 10

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

True

False

7 / 10

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

False

True

8 / 10

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

False

True

9 / 10

9. A page along with its tuples is read into the buffer cache with compression transformations to enhance cache efficiency?

True

False

10 / 10

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

CREATE

INSERT

COMMIT

DELETE

Your score is

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