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

Which fork contains the actual table data?

table map

free space map

Main fork

visiblilty map

2 / 20

A single Postgres Instance can server only one database?

False

True

3 / 20

Postgres uses a thread based process model?

True

False

4 / 20

Postgres by default has built in connection pooling abilities?

False

True

5 / 20

What is the default standard size for a fork file?

1MB

5MB

1GB

5GB

6 / 20

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

False

True

7 / 20

To be able to restore data consistency, Postgres maintains

online redo logs (ORL)

undo segments (UNDO)

rollback segments (RBS)

write-ahead log (WAL)

8 / 20

What command is used to create the Postgres cluster?

CreateCluster

CreatePGC

Initialize

StartNewPG

9 / 20

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

10 / 20

Which of below are predefined schemas?

choose 3

pg_temp

pg_schema

pg_toast

information_schema

11 / 20

It is the postmasters job to listener for incoming connections?

True

False

12 / 20

To understand each other, a client and a server must use one and the same interfacing protocol?

True

False

13 / 20

Tablespaces are used to define physical data layout?

True

False

14 / 20

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

True

False

15 / 20

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

16 / 20

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

choose 3

sequences

indexes

triggers

tables

17 / 20

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

choose 2

pg_global

pg_tablespace

pg_temp

pg_default

18 / 20

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

19 / 20

What column in system catalogs servers as the Primary Key

oid

oid#

obj

obj#

20 / 20

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

visiblilty map

table map

free space map

Main fork

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

non-repeatable read anomaly occurs when?

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 and modifies this row 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

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

choose 3

Repeatable Read

Serializable

Read Uncommitted

Read Committed

3 / 10

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

Read Committed

Serializable

Repeatable Read

Read Uncommitted

4 / 10

What is the default Isolation Level?

Read Committed

Repeatable Read

Read Uncommitted

Serializable

5 / 10

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

True

False

6 / 10

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

Select more than 1 answer below:

Issues a rollback after the commit to satisfy repeatable read.

Replace procedural code with declarative one.

Apply explicit locks

Use a single SQL operator

7 / 10

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

CREATE EXTENSTION REPEATABLE_READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

SET ISO=REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

8 / 10

Which of the below would best describe a dirty read?

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

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 commited data altered by another session

9 / 10

Which of the below are valid Isolations Levels?

choose 2

Read Committed

Rollback Read

Random Scatter

Serializable

10 / 10

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

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

indexes do not use row versioning?

False

True

2 / 10

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

False

True

3 / 10

Tuples can also be referred to as columns?

False

True

4 / 10

Information about subtransactions is stored under?

PGDATA/pg_min

PGDATA/pg_xid

PGDATA/subtrans

PGDATA/pg_subtrans

5 / 10

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

False

True

6 / 10

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

commit log

archive log

transaction log

redo log

7 / 10

Which 2 items does a Virtual XID consist of?

sequential number

backend process ID

checksum

xmin

8 / 10

Each page has a layer that usually consists of?

choose 2

undo segment

free space

flashback block

page header

9 / 10

psql provides a special mode that allows you to continue a transaction after a failure?

False

True

10 / 10

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

COMMIT

DELETE

INSERT

CREATE

Your score is

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