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

Users should not modify the template0 database

True

False

2 / 20

Which fork is specific for unlogged tables?

Main fork

Initialization fork

free space map

visiblilty map

3 / 20

What is the purpose of the public schema?

no such schema

schema used for heterogeneous replication

restricted schema for postgres internal usage only

default schema for user objects

4 / 20

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

5 / 20

What is another name for the postgres process?

postmanager

masterprocess

postmaster

aurora

6 / 20

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

True

False

7 / 20

What command is used to create the Postgres cluster?

CreateCluster

StartNewPG

Initialize

CreatePGC

8 / 20

What column in system catalogs servers as the Primary Key

obj

obj#

oid#

oid

9 / 20

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

10 / 20

Which 3 databases exist directly after cluster initialization?

choose 3 options

template0

sysaux

template1

postgres

11 / 20

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

pg_class

pg_system

pg_tables

pg_catalog

12 / 20

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

False

True

13 / 20

Tablespaces are used to define physical data layout?

True

False

14 / 20

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

False

True

15 / 20

What is the purpose of the postgres database?

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

a template for all the other database

No such database

regular database that you can use at your discretion

16 / 20

What is the name of the catalog that stores metadata for all cluster objects?

Sysasm Catalog

System Catalog

Sys Catalog

Sysaux Catalog

17 / 20

What is the point of the pg_global tablespace?

stores WAL logs used for global replication

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

18 / 20

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

table map

Main fork

free space map

visiblilty map

19 / 20

To be able to restore data consistency, Postgres maintains

undo segments (UNDO)

rollback segments (RBS)

write-ahead log (WAL)

online redo logs (ORL)

20 / 20

The default Page size is 2k?

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

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

choose 3

Read Committed

Read Uncommitted

Repeatable Read

Serializable

2 / 10

The SQL standard specifies three isolation levels?

False

True

3 / 10

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

True

False

4 / 10

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

CREATE EXTENSTION REPEATABLE_READ;

SET ISO=REPEATABLE_READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

5 / 10

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

Select more than 1 answer below:

Use a single SQL operator

Replace procedural code with declarative one.

Apply explicit locks

Issues a rollback after the commit to satisfy repeatable read.

6 / 10

Which parameters sets the database default isolation level?

default_transaction_isolation

transaction_isolation_level

default_isolation_level

active_transaction_isolation

7 / 10

Which of the below would best describe a dirty read?

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

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

reading data direct from memory using pg_dirt

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

8 / 10

What is the default Isolation Level?

Repeatable Read

Read Committed

Read Uncommitted

Serializable

9 / 10

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

False

True

10 / 10

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 issue a rollback.

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 and commits the change.

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

CLOG files are stored in which directory?

PGDATA/pg_clog

PGDATA/clog

PGDATA/pg_commit

PGDATA/pg_xact

2 / 10

CLOG contains how many bits for each transaction?

3 / 10

Page header sizes can be easily displayed using the <choose from answers> extension

pagedetect

pageinspect

pageheadinfo

pagesize

4 / 10

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

stored in PGDATA/itemptr directory

Each pointer uses 8 bytes

Each pointer uses 4 bytes

Also know as the pages table of contents

5 / 10

status of a subtransaction is written into CLOG?

True

False

6 / 10

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

magic XID

virtual XID

heap XID

temporary XID

7 / 10

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

False

True

8 / 10

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

False

True

9 / 10

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

xmin

xtime

xmax

xid

10 / 10

CLOG Pages are never cached in memory?

True

False

Your score is

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