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

True

False

2 / 20

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

False

True

3 / 20

3. Which of below are predefined schemas?

choose 3

pg_schema

information_schema

pg_toast

pg_temp

4 / 20

4. Files are logically split into pages?

True

False

5 / 20

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

1GB

1MB

5MB

5GB

6 / 20

6. System Catalog tables begin with which prefix?

pg_

cat_

sys_

dba_

7 / 20

7. Postgres uses a thread based process model?

True

False

8 / 20

8. What is the point of the pg_global tablespace?

stores system catalog objects that are common to the whole cluster

stores user tables that are common to the whole cluster

stores temporary tables that are common to the whole cluster

stores WAL logs used for global replication

9 / 20

9. What is a schema?

This is the same as a user in Postgres

A memory area used to cache data from LRU chains

Namespace that store all objects of a database

The name used to refer to a super user account

10 / 20

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

Paul Sammy

Sam Altman

Egor Rogov

Dan Brown

11 / 20

11. It is the postmasters job to listener for incoming connections?

False

True

12 / 20

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

BAKE

TOAST

BREAD

GROW

13 / 20

13. Which fork contains the actual table data?

Main fork

table map

visiblilty map

free space map

14 / 20

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

False

True

15 / 20

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

System Catalog

Sys Catalog

Sysasm Catalog

Sysaux Catalog

16 / 20

16. How many files or forks on disk will a 10Mb table with no index have?

17 / 20

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

True

False

18 / 20

18. Which fork is specific for unlogged tables?

visiblilty map

Initialization fork

Main fork

free space map

19 / 20

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

False

True

20 / 20

20. What is the purpose of autovacuum?

Rebuilds indexes with b level greater than 2

Deletes old logs and traces on disk

Performs a backup of WAL logs

Removes stale data from tables and indexes

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

SET ISO=REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

CREATE EXTENSTION REPEATABLE_READ;

2 / 10

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

True

False

3 / 10

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

True

False

4 / 10

4. 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

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

Read Uncommitted

Repeatable Read

Serializable

Read Committed

6 / 10

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

True

False

7 / 10

7. Which parameters sets the database default isolation level?

default_isolation_level

active_transaction_isolation

default_transaction_isolation

transaction_isolation_level

8 / 10

8. Lost updates are forbidden by the standard at all isolation levels?

False

True

9 / 10

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

choose 3

Read Uncommitted

Repeatable Read

Serializable

Read Committed

10 / 10

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

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

a session being able to see uncommited 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

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

False

True

2 / 10

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

True

False

3 / 10

3. CLOG Pages are never cached in memory?

False

True

4 / 10

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

Each pointer uses 8 bytes

Also know as the pages table of contents

Each pointer uses 4 bytes

stored in PGDATA/itemptr directory

5 / 10

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

INSERT

CREATE

DELETE

COMMIT

6 / 10

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

False

True

7 / 10

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

xtime

xmin

xmax

xid

8 / 10

8. indexes do not use row versioning?

False

True

9 / 10

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

True

False

10 / 10

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

pagesize

pageheadinfo

pagedetect

pageinspect

Your score is

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