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

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

False

True

2 / 20

What is the purpose of the visibility map?

shows referential relationships for tables

provides an audit trail for the database

provides the data decryption key

shows a page to be vacuumed or frozen

3 / 20

What is the name of the mechanism used to store a row bigger than a page size?

BAKE

GROW

TOAST

BREAD

4 / 20

What is the purpose of wal writer?

executes checkpoints

flushes dirty pages to disk.

writes WAL entries to disk

collects usage statistics for the instance.

5 / 20

What is the process first launched at server start?

postman

init

pginit

postgres

6 / 20

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

pg_tables

pg_class

pg_system

pg_catalog

7 / 20

What is the point of the pg_global tablespace?

stores WAL logs used for global replication

stores temporary tables that are common to the whole cluster

stores system catalog objects that are common to the whole cluster

stores user tables that are common to the whole cluster

8 / 20

System Catalog tables begin with which prefix?

cat_

sys_

dba_

pg_

9 / 20

What is a schema?

The name used to refer to a super user account

A memory area used to cache data from LRU chains

Namespace that store all objects of a database

This is the same as a user in Postgres

10 / 20

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

True

False

11 / 20

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

12 / 20

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

table map

free space map

visiblilty map

Main fork

13 / 20

The default Page size is 2k?

False

True

14 / 20

What command is used to create the Postgres cluster?

StartNewPG

CreateCluster

CreatePGC

Initialize

15 / 20

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

pg_tblspc

pg_tablespace

pg_tabspace

pg_symlinks

16 / 20

Postgres uses a thread based process model?

True

False

17 / 20

Files are logically split into pages?

False

True

18 / 20

The information_schema schema provides information on Postgres release notes?

True

False

19 / 20

TOAST tables reside in a seperate schema?

False

True

20 / 20

To be able to restore data consistency, Postgres maintains

rollback segments (RBS)

write-ahead log (WAL)

undo segments (UNDO)

online redo logs (ORL)

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

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 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

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.

2 / 10

What is the default Isolation Level?

Serializable

Read Uncommitted

Repeatable Read

Read Committed

3 / 10

Which of the below are valid Isolations Levels?

choose 2

Rollback Read

Read Committed

Serializable

Random Scatter

4 / 10

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

False

True

5 / 10

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

False

True

6 / 10

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

True

False

7 / 10

Which parameters sets the database default isolation level?

default_isolation_level

transaction_isolation_level

default_transaction_isolation

active_transaction_isolation

8 / 10

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

False

True

9 / 10

Which of the below would best describe a dirty read?

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

reading data direct from memory using pg_dirt

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

10 / 10

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

Issues a rollback after the commit to satisfy repeatable read.

Use a single SQL operator

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

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

True

False

2 / 10

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

False

True

3 / 10

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

xid

xmax

xtime

xmin

4 / 10

CLOG Pages are never cached in memory?

False

True

5 / 10

indexes do not use row versioning?

True

False

6 / 10

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

pageheadinfo

pagesize

pagedetect

pageinspect

7 / 10

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

transaction log

redo log

commit log

archive log

8 / 10

Tuples can also be referred to as columns?

True

False

9 / 10

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

pg_current_xact_id()

pg_current_id()

pg_current_xmin_id()

pg_current_commit_id()

10 / 10

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

stored in PGDATA/itemptr directory

Also know as the pages table of contents

Each pointer uses 8 bytes

Each pointer uses 4 bytes

Your score is

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