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 template1 database?

database used for temporary tables

a template for all the other databases

No such database

regular database that you can use at your discretion

2 / 20

2. What is the purpose of the public schema?

default schema for user objects

no such schema

restricted schema for postgres internal usage only

schema used for heterogeneous replication

3 / 20

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

True

False

4 / 20

4. Which 3 databases exist directly after cluster initialization?

choose 3 options

sysaux

template0

template1

postgres

5 / 20

5. What is the purpose of wal writer?

flushes dirty pages to disk.

executes checkpoints

writes WAL entries to disk

collects usage statistics for the instance.

6 / 20

6. Which of below are predefined schemas?

choose 2

system

public

postgres

pg_catalog

7 / 20

7. Files are logically split into pages?

True

False

8 / 20

8. What is the name of the system catalog table for relations?

pg_tables

pg_class

pg_system

pg_catalog

9 / 20

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

False

True

10 / 20

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

False

True

11 / 20

11. The default Page size is 2k?

False

True

12 / 20

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

True

False

13 / 20

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

StartNewPG

Initialize

CreateCluster

CreatePGC

14 / 20

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

True

False

15 / 20

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

write-ahead log (WAL)

online redo logs (ORL)

undo segments (UNDO)

rollback segments (RBS)

16 / 20

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

choose 3

tables

sequences

indexes

triggers

17 / 20

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

False

True

18 / 20

18. Which of below are predefined schemas?

choose 3

pg_temp

pg_schema

pg_toast

information_schema

19 / 20

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

PGDATA

PGCORE

PGBASE

PGTIPS

20 / 20

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

table map

free space map

Main fork

visiblilty map

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?

transaction_isolation_level

active_transaction_isolation

default_transaction_isolation

default_isolation_level

2 / 10

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

choose 3

Read Uncommitted

Repeatable Read

Serializable

Read Committed

3 / 10

3. Which of the below are valid Isolations Levels?

choose 2

Serializable

Read Committed

Random Scatter

Rollback Read

4 / 10

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

True

False

5 / 10

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

True

False

6 / 10

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

reading data direct from memory using pg_dirt

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

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

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

7 / 10

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

Read Uncommitted

Read Committed

Serializable

Repeatable Read

8 / 10

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

False

True

9 / 10

9. 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 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.

10 / 10

10. The SQL standard specifies three isolation levels?

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. Tuples can also be referred to as columns?

True

False

2 / 10

2. Which 2 of the below represent transaction IDs used for row versioning?

xtime

xid

xmin

xmax

3 / 10

3. CLOG files are stored in which directory?

PGDATA/pg_xact

PGDATA/pg_commit

PGDATA/clog

PGDATA/pg_clog

4 / 10

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

False

True

5 / 10

5. CLOG Pages are never cached in memory?

True

False

6 / 10

6. Page free space can often become fragmented?

False

True

7 / 10

7. Which of the below are true about a Pages Item Pointer?

Also know as the pages table of contents

Each pointer uses 4 bytes

stored in PGDATA/itemptr directory

Each pointer uses 8 bytes

8 / 10

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

False

True

9 / 10

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

False

True

10 / 10

10. What does an Item Pointer contain?

choose 3

tuple status

tuple offset from the start of the page

tuple xid

tuple length

Your score is

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