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

pg_catalog schema is used to store system catalog tables?

False

True

2 / 20

To be able to restore data consistency, Postgres maintains

write-ahead log (WAL)

rollback segments (RBS)

online redo logs (ORL)

undo segments (UNDO)

3 / 20

Which 3 databases exist directly after cluster initialization?

choose 3 options

template1

postgres

template0

sysaux

4 / 20

Postgres server spawns a new backend session for each connection?

False

True

5 / 20

What is the purpose of the visibility map?

provides an audit trail for the database

shows referential relationships for tables

provides the data decryption key

shows a page to be vacuumed or frozen

6 / 20

What is the point of the pg_global tablespace?

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

stores WAL logs used for global replication

7 / 20

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

True

False

8 / 20

What is the purpose of autovacuum?

Removes stale data from tables and indexes

Rebuilds indexes with b level greater than 2

Performs a backup of WAL logs

Deletes old logs and traces on disk

9 / 20

When PostgreSQL is running what can it be referred to as?

Choose 2 option

Aurora

Postgres Server

Quorum

Instance

10 / 20

TOAST tables reside in a seperate schema?

True

False

11 / 20

Which of below are predefined schemas?

choose 3

information_schema

pg_toast

pg_temp

pg_schema

12 / 20

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

BAKE

GROW

TOAST

BREAD

13 / 20

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

pg_tablespace

pg_symlinks

pg_tabspace

pg_tblspc

14 / 20

What is the default standard size for a fork file?

5GB

1GB

1MB

5MB

15 / 20

What is the purpose of the postgres database?

a template for all the other database

No such database

regular database that you can use at your discretion

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

16 / 20

What is the purpose of wal writer?

executes checkpoints

writes WAL entries to disk

collects usage statistics for the instance.

flushes dirty pages to disk.

17 / 20

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

True

False

18 / 20

Each tablespaces can only be assigned for use by one database

True

False

19 / 20

It is the postmasters job to listener for incoming connections?

False

True

20 / 20

Each Database has its own System Catalog?

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

Which of the below would best describe a dirty read?

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

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

2 / 10

What is the default Isolation Level?

Repeatable Read

Serializable

Read Committed

Read Uncommitted

3 / 10

Which parameters sets the database default isolation level?

default_transaction_isolation

default_isolation_level

active_transaction_isolation

transaction_isolation_level

4 / 10

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

ALTER SYSTEM SET ISO=REPEATABLE_READ;

SET ISO=REPEATABLE_READ;

CREATE EXTENSTION REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

5 / 10

A phantom read anomaly occurs when?

A transactions inserts a null value into a not null columns 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.

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.

6 / 10

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

ACID

HIPPA

SOC2

SAFE

7 / 10

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

True

False

8 / 10

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

choose 3

Serializable

Read Uncommitted

Read Committed

Repeatable Read

9 / 10

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

Read Uncommitted

Repeatable Read

Read Committed

Serializable

10 / 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.

Use a single SQL operator

Apply explicit locks

Replace procedural code with declarative one.

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

at any one time Postgres can have several versions of a row?

True

False

2 / 10

Page free space can often become fragmented?

False

True

3 / 10

Each page has a layer that usually consists of?

choose 2

flashback block

undo segment

free space

page header

4 / 10

If a transaction aborts, all page changes are reverted(rolled back) in place?

True

False

5 / 10

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

False

True

6 / 10

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

True

False

7 / 10

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

False

True

8 / 10

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

pg_current_commit_id()

pg_current_id()

pg_current_xmin_id()

pg_current_xact_id()

9 / 10

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

False

True

10 / 10

CLOG Pages are never cached in memory?

False

True

Your score is

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