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_temp

pg_global

2 / 20

2. A Postgres cluster consists of 2 or more physical servers accessing one Postgres Instance?

True

False

3 / 20

3. Which of below are predefined schemas?

choose 2

system

pg_catalog

postgres

public

4 / 20

4. Which 3 databases exist directly after cluster initialization?

choose 3 options

template1

postgres

template0

sysaux

5 / 20

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

False

True

6 / 20

6. TOAST tables reside in a seperate schema?

False

True

7 / 20

7. What is the purpose of the template1 database?

No such database

database used for temporary tables

regular database that you can use at your discretion

a template for all the other databases

8 / 20

8. Which of below are predefined schemas?

choose 3

pg_temp

pg_schema

pg_toast

information_schema

9 / 20

9. Which fork is specific for unlogged tables?

Main fork

Initialization fork

visiblilty map

free space map

10 / 20

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

StartNewPG

CreatePGC

Initialize

CreateCluster

11 / 20

11. What is the purpose of wal writer?

writes WAL entries to disk

flushes dirty pages to disk.

collects usage statistics for the instance.

executes checkpoints

12 / 20

12. What is a schema?

Namespace that store all objects of a database

This is the same as a user in Postgres

The name used to refer to a super user account

A memory area used to cache data from LRU chains

13 / 20

13. Postgres server spawns a new backend session for each connection?

True

False

14 / 20

14. What is the purpose of autovacuum?

Deletes old logs and traces on disk

Removes stale data from tables and indexes

Rebuilds indexes with b level greater than 2

Performs a backup of WAL logs

15 / 20

15. What is the point of the pg_global tablespace?

stores user tables that are common to the whole cluster

stores system catalog objects that are common to the whole cluster

stores temporary tables that are common to the whole cluster

stores WAL logs used for global replication

16 / 20

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

free space map

visiblilty map

Main fork

table map

17 / 20

17. It is the postmasters job to listener for incoming connections?

True

False

18 / 20

18. Postgres uses a thread based process model?

True

False

19 / 20

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

False

True

20 / 20

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

pg_tables

pg_catalog

pg_system

pg_class

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 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.

2 / 10

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

Read Uncommitted

Repeatable Read

Serializable

Read Committed

3 / 10

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

Select more than 1 answer below:

Replace procedural code with declarative one.

Apply explicit locks

Use a single SQL operator

Issues a rollback after the commit to satisfy repeatable read.

4 / 10

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

False

True

5 / 10

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

SOC2

SAFE

HIPPA

ACID

6 / 10

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

False

True

7 / 10

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

False

True

8 / 10

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

True

False

9 / 10

9. The SQL standard specifies three isolation levels?

True

False

10 / 10

10. What is the default Isolation Level?

Read Uncommitted

Read Committed

Serializable

Repeatable Read

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 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

2 / 10

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

xtime

xid

xmin

xmax

3 / 10

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

False

True

4 / 10

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

True

False

5 / 10

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

False

True

6 / 10

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

COMMIT

CREATE

DELETE

INSERT

7 / 10

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

backend process ID

checksum

xmin

sequential number

8 / 10

8. CLOG Pages are never cached in memory?

False

True

9 / 10

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

xmas

xid

xmin

xmax

10 / 10

10. What does an Item Pointer contain?

choose 3

tuple status

tuple xid

tuple offset from the start of the page

tuple length

Your score is

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