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

1. What is a schema?

This is the same as a user in Postgres

The name used to refer to a super user account

A memory area used to cache data from LRU chains

Namespace that store all objects of a database

2 / 20

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

Main fork

table map

free space map

visiblilty map

3 / 20

3. Who is the Author of the Postgres 14 Internals book?

Sam Altman

Dan Brown

Egor Rogov

Paul Sammy

4 / 20

4. pg_catalog schema is used to store system catalog tables?

True

False

5 / 20

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

False

True

6 / 20

6. What is the purpose of wal writer?

writes WAL entries to disk

executes checkpoints

collects usage statistics for the instance.

flushes dirty pages to disk.

7 / 20

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

Choose 2 option

Instance

Postgres Server

Quorum

Aurora

8 / 20

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

PGCORE

PGBASE

PGTIPS

PGDATA

9 / 20

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

False

True

10 / 20

10. To understand each other, a client and a server must use one and the same interfacing protocol?

False

True

11 / 20

11. What is the purpose of the template0 database?

No such database

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

Useful for creating development schemas

Useful for Postgres support Services to debug issues

12 / 20

12. What is the default standard size for a fork file?

1MB

5GB

5MB

1GB

13 / 20

13. The default Page size is 2k?

True

False

14 / 20

14. Postgres by default has built in connection pooling abilities?

False

True

15 / 20

15. System Catalog tables begin with which prefix?

dba_

cat_

pg_

sys_

16 / 20

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

pg_tblspc

pg_tabspace

pg_tablespace

pg_symlinks

17 / 20

17. Postgres server spawns a new backend session for each connection?

False

True

18 / 20

18. A single Postgres Instance can server only one database?

True

False

19 / 20

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

20 / 20

20. Which fork contains the actual table data?

visiblilty map

free space map

table map

Main 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

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

2 / 10

2. The SQL standard specifies three isolation levels?

False

True

3 / 10

3. 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

4. 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 also queries this same data.

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 adds some other rows satisfying this condition and commits.

5 / 10

5. Which parameters sets the database default isolation level?

transaction_isolation_level

default_transaction_isolation

active_transaction_isolation

default_isolation_level

6 / 10

6. Which of the below would best describe a dirty read?

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

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

reading data direct from memory using pg_dirt

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

7 / 10

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

Select more than 1 answer below:

Apply explicit locks

Issues a rollback after the commit to satisfy repeatable read.

Use a single SQL operator

Replace procedural code with declarative one.

8 / 10

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

choose 3

Repeatable Read

Serializable

Read Uncommitted

Read Committed

9 / 10

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

False

True

10 / 10

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

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

1. Which 2 of the below represent transaction IDs used for row versioning?

xmax

xtime

xid

xmin

2 / 10

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

False

True

3 / 10

3. What does an Item Pointer contain?

choose 3

tuple length

tuple xid

tuple status

tuple offset from the start of the page

4 / 10

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

Each pointer uses 8 bytes

stored in PGDATA/itemptr directory

Also know as the pages table of contents

Each pointer uses 4 bytes

5 / 10

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

DELETE

COMMIT

INSERT

CREATE

6 / 10

6. Indexes values also support multi versioning with several versions of an index value existing at any point in time?

False

True

7 / 10

7. Each page has a layer that usually consists of?

choose 2

flashback block

undo segment

page header

free space

8 / 10

8. The page header is located in the highest address?

False

True

9 / 10

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

redo log

transaction log

commit log

archive log

10 / 10

10. status of a subtransaction is written into CLOG?

True

False

Your score is

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