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 purpose of wal writer?

writes WAL entries to disk

flushes dirty pages to disk.

executes checkpoints

collects usage statistics for the instance.

2 / 20

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

True

False

3 / 20

The information_schema schema provides information on Postgres release notes?

True

False

4 / 20

Postgres uses a thread based process model?

True

False

5 / 20

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

False

True

6 / 20

Postgres by default has built in connection pooling abilities?

True

False

7 / 20

System Catalog tables begin with which prefix?

cat_

pg_

sys_

dba_

8 / 20

Postgres server spawns a new backend session for each connection?

True

False

9 / 20

What is the default standard size for a fork file?

5GB

5MB

1GB

1MB

10 / 20

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

False

True

11 / 20

A single Postgres Instance can server only one database?

False

True

12 / 20

Which 3 databases exist directly after cluster initialization?

choose 3 options

template0

sysaux

postgres

template1

13 / 20

Which fork contains the actual table data?

table map

Main fork

visiblilty map

free space map

14 / 20

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

Choose 2 option

Quorum

Aurora

Postgres Server

Instance

15 / 20

Files are logically split into pages?

True

False

16 / 20

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

Sys Catalog

Sysasm Catalog

Sysaux Catalog

System Catalog

17 / 20

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

Schema Path

Search Path

Directory Path

Access Path

18 / 20

To be able to restore data consistency, Postgres maintains

undo segments (UNDO)

online redo logs (ORL)

rollback segments (RBS)

write-ahead log (WAL)

19 / 20

Each Database has its own System Catalog?

False

True

20 / 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

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

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

choose 3

Read Committed

Serializable

Repeatable Read

Read Uncommitted

2 / 10

Which of the below would best describe a dirty read?

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

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

reading data direct from memory using pg_dirt

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

3 / 10

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

CREATE EXTENSTION REPEATABLE_READ;

SET ISO=REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

4 / 10

A phantom read anomaly occurs when?

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.

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.

5 / 10

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

True

False

6 / 10

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

Read Uncommitted

Repeatable Read

Serializable

Read Committed

7 / 10

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

False

True

8 / 10

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

HIPPA

SAFE

ACID

SOC2

9 / 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 twice, another transaction modifies this row between these reads and commits the change.

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 once and modifies this row and commits the change.

10 / 10

The SQL standard specifies three isolation levels?

True

False

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

In Postgres, tables are often referred to as which of the below?

view

heap

clog

dump

2 / 10

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

True

False

3 / 10

The page header is located in the highest address?

False

True

4 / 10

UPDATE can be regarded as which 2 separate operations?

COMMIT

MERGE

INSERT

DELETE

5 / 10

virtual IDs exist only in PGDATA/pg_vxid when not cached?

True

False

6 / 10

Each page has a layer that usually consists of?

choose 2

page header

undo segment

flashback block

free space

7 / 10

CLOG files are stored in which directory?

PGDATA/pg_commit

PGDATA/pg_xact

PGDATA/pg_clog

PGDATA/clog

8 / 10

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

pageheadinfo

pagedetect

pagesize

pageinspect

9 / 10

CLOG contains how many bits for each transaction?

10 / 10

Tuples can also be referred to as columns?

False

True

Your score is

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