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

Postgres uses a thread based process model?

True

False

2 / 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

This is the same as a user in Postgres

Namespace that store all objects of a database

3 / 20

Which 3 databases exist directly after cluster initialization?

choose 3 options

sysaux

template1

template0

postgres

4 / 20

What is the process first launched at server start?

postgres

postman

init

pginit

5 / 20

Users should not modify the template0 database

True

False

6 / 20

Which fork keeps track of available space within pages?

vacuum space map

free space map

used space map

wal space map

7 / 20

A single Postgres Instance can server only one database?

False

True

8 / 20

What is the purpose of autovacuum?

Removes stale data from tables and indexes

Performs a backup of WAL logs

Deletes old logs and traces on disk

Rebuilds indexes with b level greater than 2

9 / 20

pg_catalog schema is used to store system catalog tables?

True

False

10 / 20

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

True

False

11 / 20

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

TOAST

GROW

BREAD

BAKE

12 / 20

What is the purpose of wal writer?

collects usage statistics for the instance.

writes WAL entries to disk

flushes dirty pages to disk.

executes checkpoints

13 / 20

To be able to restore data consistency, Postgres maintains

undo segments (UNDO)

rollback segments (RBS)

online redo logs (ORL)

write-ahead log (WAL)

14 / 20

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

pg_symlinks

pg_tablespace

pg_tabspace

pg_tblspc

15 / 20

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

True

False

16 / 20

TOAST tables reside in a seperate schema?

False

True

17 / 20

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

choose 2

pg_tablespace

pg_default

pg_temp

pg_global

18 / 20

Postgres server spawns a new backend session for each connection?

True

False

19 / 20

What is the name of the directory that contains the files related to the Postgres cluster?

PGDATA

PGTIPS

PGCORE

PGBASE

20 / 20

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

choose 3

indexes

triggers

sequences

tables

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

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.

2 / 10

What is the default Isolation Level?

Read Committed

Repeatable Read

Read Uncommitted

Serializable

3 / 10

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

False

True

4 / 10

Which of the below would best describe a dirty read?

reading data direct from memory using pg_dirt

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

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

5 / 10

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

False

True

6 / 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 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 and commits the change.

A transaction reads one and the same row once and modifies this row and commits the change.

7 / 10

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

BEGIN ISOLATION LEVEL REPEATABLE READ;

CREATE EXTENSTION REPEATABLE_READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

SET ISO=REPEATABLE_READ;

8 / 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 also queries this same data.

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.

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

9 / 10

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

False

True

10 / 10

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

SOC2

ACID

SAFE

HIPPA

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

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

DELETE

COMMIT

INSERT

CREATE

2 / 10

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

False

True

3 / 10

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

True

False

4 / 10

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

True

False

5 / 10

a transaction containing a savepoint is will still be considered as only a single transaction?

False

True

6 / 10

CLOG Pages are never cached in memory?

False

True

7 / 10

To identify different versions of one and the same row, PostgreSQL marks each of them with which two value?

xid

xmin

xmax

xmas

8 / 10

CLOG contains how many bits for each transaction?

9 / 10

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

Each pointer uses 4 bytes

Each pointer uses 8 bytes

stored in PGDATA/itemptr directory

Also know as the pages table of contents

10 / 10

index row headers like table row headers contain xmin and xmax fields?

True

False

Your score is

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