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 information_schema schema provides information on Postgres release notes?

True

False

2 / 20

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

Sysaux Catalog

Sys Catalog

System Catalog

Sysasm Catalog

3 / 20

To be able to restore data consistency, Postgres maintains

undo segments (UNDO)

write-ahead log (WAL)

online redo logs (ORL)

rollback segments (RBS)

4 / 20

Users should not modify the template0 database

False

True

5 / 20

A single Postgres Instance can server only one database?

True

False

6 / 20

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

choose 2

pg_default

pg_temp

pg_tablespace

pg_global

7 / 20

System Catalog tables begin with which prefix?

pg_

cat_

dba_

sys_

8 / 20

What is the purpose of the postgres database?

a template for all the other database

No such database

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

regular database that you can use at your discretion

9 / 20

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

pg_class

pg_tables

pg_system

pg_catalog

10 / 20

Which of below are predefined schemas?

choose 2

system

public

postgres

pg_catalog

11 / 20

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

GROW

BREAD

BAKE

TOAST

12 / 20

How does Postgres know which schema to use if not specified?

Schema Path

Search Path

Directory Path

Access Path

13 / 20

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

False

True

14 / 20

Which of below are predefined schemas?

choose 3

pg_schema

pg_toast

information_schema

pg_temp

15 / 20

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

True

False

16 / 20

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

17 / 20

What is the process first launched at server start?

init

postgres

postman

pginit

18 / 20

Each tablespaces can only be assigned for use by one database

False

True

19 / 20

What is the default standard size for a fork file?

1GB

5GB

5MB

1MB

20 / 20

Which fork is specific for unlogged tables?

Main fork

visiblilty map

free space map

Initialization 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

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

False

True

2 / 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

3 / 10

Which of the below are valid Isolations Levels?

choose 2

Rollback Read

Read Committed

Random Scatter

Serializable

4 / 10

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

choose 3

Read Uncommitted

Repeatable Read

Serializable

Read Committed

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

Apply explicit locks

Issues a rollback after the commit to satisfy repeatable read.

Replace procedural code with declarative one.

6 / 10

A phantom read anomaly occurs when?

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 adds some other rows satisfying this condition and commits.

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.

A transactions inserts a null value into a not null columns and commits

7 / 10

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

True

False

8 / 10

Which parameters sets the database default isolation level?

default_isolation_level

active_transaction_isolation

transaction_isolation_level

default_transaction_isolation

9 / 10

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

Serializable

Read Uncommitted

Repeatable Read

Read Committed

10 / 10

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

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

status of a subtransaction is written into CLOG?

False

True

2 / 10

What does an Item Pointer contain?

choose 3

tuple status

tuple length

tuple xid

tuple offset from the start of the page

3 / 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()

4 / 10

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

stored in PGDATA/itemptr directory

Each pointer uses 8 bytes

Also know as the pages table of contents

Each pointer uses 4 bytes

5 / 10

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

False

True

6 / 10

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

False

True

7 / 10

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

transaction log

commit log

redo log

archive log

8 / 10

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

INSERT

COMMIT

DELETE

CREATE

9 / 10

Tuples can also be referred to as columns?

False

True

10 / 10

Page free space can often become fragmented?

False

True

Your score is

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