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 restoring data from a logical backup or creating a database with a different encoding

Useful for creating development schemas

2 / 20

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

StartNewPG

Initialize

CreateCluster

CreatePGC

3 / 20

3. Postgres uses a thread based process model?

True

False

4 / 20

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

1MB

5GB

5MB

1GB

5 / 20

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

choose 2

pg_global

pg_default

pg_tablespace

pg_temp

6 / 20

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

True

False

7 / 20

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

True

False

8 / 20

8. Which of below are predefined schemas?

choose 3

information_schema

pg_schema

pg_toast

pg_temp

9 / 20

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

True

False

10 / 20

10. 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

11 / 20

11. If we create a new tablespace which directory will symbolic links be created from?

pg_tblspc

pg_tabspace

pg_tablespace

pg_symlinks

12 / 20

12. Which fork contains the actual table data?

table map

Main fork

visiblilty map

free space map

13 / 20

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

False

True

14 / 20

14. What is the point of the pg_global tablespace?

stores system catalog objects that are common to the whole cluster

stores WAL logs used for global replication

stores user tables that are common to the whole cluster

stores temporary tables that are common to the whole cluster

15 / 20

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

16 / 20

16. What is a schema?

A memory area used to cache data from LRU chains

Namespace that store all objects of a database

The name used to refer to a super user account

This is the same as a user in Postgres

17 / 20

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

pginit

postman

init

postgres

18 / 20

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

19 / 20

19. System Catalog tables begin with which prefix?

cat_

pg_

dba_

sys_

20 / 20

20. pg_catalog schema is used to store system catalog tables?

True

False

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

False

True

2 / 10

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

False

True

3 / 10

3. Which parameters sets the database default isolation level?

default_transaction_isolation

default_isolation_level

active_transaction_isolation

transaction_isolation_level

4 / 10

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

choose 3

Read Uncommitted

Repeatable Read

Serializable

Read Committed

5 / 10

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

SOC2

ACID

SAFE

HIPPA

6 / 10

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

Read Uncommitted

Serializable

Repeatable Read

Read Committed

7 / 10

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

Select more than 1 answer below:

Apply explicit locks

Use a single SQL operator

Replace procedural code with declarative one.

Issues a rollback after the commit to satisfy repeatable read.

8 / 10

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

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

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

reading data direct from memory using pg_dirt

9 / 10

9. A phantom read anomaly occurs when?

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.

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

10 / 10

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

CREATE EXTENSTION REPEATABLE_READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

SET ISO=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. Each page has a layer that usually consists of?

choose 2

page header

flashback block

free space

undo segment

2 / 10

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

False

True

3 / 10

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

True

False

4 / 10

4. indexes do not use row versioning?

True

False

5 / 10

5. 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

6 / 10

6. CLOG contains how many bits for each transaction?

7 / 10

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

pg_current_xmin_id()

pg_current_id()

pg_current_commit_id()

pg_current_xact_id()

8 / 10

8. In Postgres, tables are often referred to as which of the below?

clog

view

heap

dump

9 / 10

9. If a transaction is read only which kind of Transaction ID is it allocated?

temporary XID

magic XID

heap XID

virtual XID

10 / 10

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

False

True

Your score is

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