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 process first launched at server start?

postman

pginit

init

postgres

2 / 20

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

True

False

3 / 20

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

rollback segments (RBS)

online redo logs (ORL)

write-ahead log (WAL)

undo segments (UNDO)

4 / 20

4. The default Page size is 2k?

True

False

5 / 20

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

True

False

6 / 20

6. 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

7 / 20

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

5GB

5MB

1GB

1MB

8 / 20

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

BAKE

GROW

BREAD

TOAST

9 / 20

9. Which fork is specific for unlogged tables?

Main fork

visiblilty map

free space map

Initialization fork

10 / 20

10. What is the purpose of the template1 database?

database used for temporary tables

a template for all the other databases

regular database that you can use at your discretion

No such database

11 / 20

11. Which 3 databases exist directly after cluster initialization?

choose 3 options

template0

template1

sysaux

postgres

12 / 20

12. A schema can belong to more than one database?

False

True

13 / 20

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

False

True

14 / 20

14. What is the purpose of wal writer?

collects usage statistics for the instance.

flushes dirty pages to disk.

writes WAL entries to disk

executes checkpoints

15 / 20

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

True

False

16 / 20

16. Postgres uses a thread based process model?

False

True

17 / 20

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

18 / 20

18. TOAST tables reside in a seperate schema?

True

False

19 / 20

19. Which of below are predefined schemas?

choose 3

pg_temp

information_schema

pg_toast

pg_schema

20 / 20

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

choose 2

pg_tablespace

pg_global

pg_temp

pg_default

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 statements will start a transaction as Read Repeatable?

CREATE EXTENSTION REPEATABLE_READ;

SET ISO=REPEATABLE_READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

2 / 10

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

HIPPA

SOC2

SAFE

ACID

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. What is the default Isolation Level?

Serializable

Read Uncommitted

Repeatable Read

Read Committed

5 / 10

5. The more locks a transaction acquires, the better it is isolated from other transactions?

True

False

6 / 10

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

True

False

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

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

8 / 10

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

reading data direct from memory using pg_dirt

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

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

9 / 10

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

True

False

10 / 10

10. Based on Snapshot Isolation use of MVCC which of the below are permitted?

choose 3

Repeatable Read

Read Uncommitted

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

True

False

2 / 10

2. CLOG files are stored in which directory?

PGDATA/pg_xact

PGDATA/pg_clog

PGDATA/pg_commit

PGDATA/clog

3 / 10

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

xmax

xmas

xid

xmin

4 / 10

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

False

True

5 / 10

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

pageheadinfo

pageinspect

pagesize

pagedetect

6 / 10

6. Which function can we use to find the current transaction ID?

pg_current_id()

pg_current_xact_id()

pg_current_commit_id()

pg_current_xmin_id()

7 / 10

7. status of a subtransaction is written into CLOG?

False

True

8 / 10

8. Each page has a layer that usually consists of?

choose 2

page header

free space

undo segment

flashback block

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. Information about subtransactions is stored under?

PGDATA/subtrans

PGDATA/pg_xid

PGDATA/pg_subtrans

PGDATA/pg_min

Your score is

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