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 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

2 / 20

2. Which fork contains the actual table data?

visiblilty map

table map

free space map

Main fork

3 / 20

3. What is the purpose of the visibility map?

shows referential relationships for tables

provides the data decryption key

shows a page to be vacuumed or frozen

provides an audit trail for the database

4 / 20

4. Which of below are predefined schemas?

choose 2

public

pg_catalog

system

postgres

5 / 20

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

Choose 2 option

Instance

Postgres Server

Quorum

Aurora

6 / 20

6. Which 3 databases exist directly after cluster initialization?

choose 3 options

postgres

sysaux

template1

template0

7 / 20

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

obj

oid#

obj#

oid

8 / 20

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

False

True

9 / 20

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

pginit

init

postgres

postman

10 / 20

10. What is the purpose of autovacuum?

Deletes old logs and traces on disk

Performs a backup of WAL logs

Rebuilds indexes with b level greater than 2

Removes stale data from tables and indexes

11 / 20

11. Which of below are predefined schemas?

choose 3

information_schema

pg_toast

pg_temp

pg_schema

12 / 20

12. 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.

13 / 20

13. Each Database has its own System Catalog?

False

True

14 / 20

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

PGDATA

PGBASE

PGCORE

PGTIPS

15 / 20

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

False

True

16 / 20

16. What is a schema?

A memory area used to cache data from LRU chains

The name used to refer to a super user account

Namespace that store all objects of a database

This is the same as a user in Postgres

17 / 20

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

TOAST

BREAD

BAKE

GROW

18 / 20

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

undo segments (UNDO)

write-ahead log (WAL)

rollback segments (RBS)

online redo logs (ORL)

19 / 20

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

False

True

20 / 20

20. Tablespaces are used to define physical data layout?

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

False

True

2 / 10

2. non-repeatable read anomaly occurs when?

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.

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.

3 / 10

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

choose 3

Read Uncommitted

Serializable

Repeatable Read

Read Committed

4 / 10

4. Which parameters sets the database default isolation level?

active_transaction_isolation

default_transaction_isolation

transaction_isolation_level

default_isolation_level

5 / 10

5. A phantom read anomaly occurs when?

A transactions inserts a null value into a not null columns 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 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.

6 / 10

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

Read Committed

Read Uncommitted

Serializable

Repeatable Read

7 / 10

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

False

True

8 / 10

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

SOC2

HIPPA

SAFE

ACID

9 / 10

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

True

False

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

True

False

2 / 10

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

True

False

3 / 10

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

xmax

xid

xmin

xmas

4 / 10

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

False

True

5 / 10

5. When a transaction is committed Postgres uses a special <replace with answer> structure?

transaction log

archive log

redo log

commit log

6 / 10

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

choose 2

page header

flashback block

undo segment

free space

7 / 10

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

False

True

8 / 10

8. UPDATE can be regarded as which 2 separate operations?

COMMIT

DELETE

MERGE

INSERT

9 / 10

9. If a transaction aborts, all page changes are reverted(rolled back) in place?

False

True

10 / 10

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

True

False

Your score is

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