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

What is the point of the pg_global tablespace?

stores user tables that are common to the whole cluster

stores temporary tables that are common to the whole cluster

stores system catalog objects that are common to the whole cluster

stores WAL logs used for global replication

2 / 20

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

choose 3

indexes

sequences

triggers

tables

3 / 20

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

True

False

4 / 20

System Catalog tables begin with which prefix?

sys_

cat_

pg_

dba_

5 / 20

Users should not modify the template0 database

False

True

6 / 20

Which fork is specific for unlogged tables?

free space map

Main fork

Initialization fork

visiblilty map

7 / 20

What is the purpose of wal writer?

executes checkpoints

flushes dirty pages to disk.

collects usage statistics for the instance.

writes WAL entries to disk

8 / 20

Which fork keeps track of available space within pages?

wal space map

free space map

used space map

vacuum space map

9 / 20

What is the purpose of the public schema?

no such schema

default schema for user objects

schema used for heterogeneous replication

restricted schema for postgres internal usage only

10 / 20

A schema can belong to more than one database?

False

True

11 / 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

12 / 20

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

False

True

13 / 20

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

True

False

14 / 20

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

Schema Path

Directory Path

Search Path

Access Path

15 / 20

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

visiblilty map

Main fork

free space map

table map

16 / 20

What is the default standard size for a fork file?

5GB

1GB

1MB

5MB

17 / 20

Which fork contains the actual table data?

visiblilty map

free space map

table map

Main fork

18 / 20

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

Choose 2 option

Quorum

Instance

Postgres Server

Aurora

19 / 20

What command is used to create the Postgres cluster?

StartNewPG

Initialize

CreateCluster

CreatePGC

20 / 20

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

False

True

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 SQL standard specifies three isolation levels?

False

True

2 / 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.

3 / 10

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

SOC2

ACID

HIPPA

SAFE

4 / 10

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

False

True

5 / 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 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 transactions issues a commit, then a rollback to restore data to its original value

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

6 / 10

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

CREATE EXTENSTION REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

SET ISO=REPEATABLE_READ;

7 / 10

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

False

True

8 / 10

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

Select more than 1 answer below:

Apply explicit locks

Use a single SQL operator

Replace procedural code with declarative one.

Issues a rollback after the commit to satisfy repeatable read.

9 / 10

Which parameters sets the database default isolation level?

default_transaction_isolation

transaction_isolation_level

active_transaction_isolation

default_isolation_level

10 / 10

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

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

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

False

True

2 / 10

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

xid

xmas

xmin

xmax

3 / 10

The page header is located in the highest address?

False

True

4 / 10

Information about subtransactions is stored under?

PGDATA/pg_xid

PGDATA/pg_min

PGDATA/subtrans

PGDATA/pg_subtrans

5 / 10

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

pg_current_xact_id()

pg_current_xmin_id()

pg_current_id()

pg_current_commit_id()

6 / 10

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

commit log

archive log

redo log

transaction log

7 / 10

Each page has a layer that usually consists of?

choose 2

flashback block

undo segment

free space

page header

8 / 10

Tuples can also be referred to as columns?

False

True

9 / 10

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

False

True

10 / 10

Postgres table physical data files are always cross compatible across platforms?

False

True

Your score is

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