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. Users should not modify the template0 database

False

True

2 / 20

2. The default Page size is 2k?

True

False

3 / 20

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

False

True

4 / 20

4. Tablespaces are used to define physical data layout?

False

True

5 / 20

5. Files are logically split into pages?

False

True

6 / 20

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

7 / 20

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

True

False

8 / 20

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

choose 3

indexes

tables

sequences

triggers

9 / 20

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

False

True

10 / 20

10. Which fork is specific for unlogged tables?

visiblilty map

Main fork

Initialization fork

free space map

11 / 20

11. What is the purpose of the visibility map?

provides the data decryption key

provides an audit trail for the database

shows referential relationships for tables

shows a page to be vacuumed or frozen

12 / 20

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

Sysasm Catalog

Sysaux Catalog

Sys Catalog

System Catalog

13 / 20

13. What is a schema?

The name used to refer to a super user account

A memory area used to cache data from LRU chains

This is the same as a user in Postgres

Namespace that store all objects of a database

14 / 20

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

1MB

5GB

5MB

1GB

15 / 20

15. To be able to restore data consistency, Postgres maintains

rollback segments (RBS)

online redo logs (ORL)

undo segments (UNDO)

write-ahead log (WAL)

16 / 20

16. Which of below are predefined schemas?

choose 3

pg_toast

pg_schema

information_schema

pg_temp

17 / 20

17. Which of below are predefined schemas?

choose 2

public

system

postgres

pg_catalog

18 / 20

18. Postgres uses a thread based process model?

True

False

19 / 20

19. What is the purpose of autovacuum?

Deletes old logs and traces on disk

Removes stale data from tables and indexes

Performs a backup of WAL logs

Rebuilds indexes with b level greater than 2

20 / 20

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

pg_tabspace

pg_symlinks

pg_tblspc

pg_tablespace

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 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

2 / 10

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

True

False

3 / 10

3. Which parameters sets the database default isolation level?

active_transaction_isolation

default_isolation_level

transaction_isolation_level

default_transaction_isolation

4 / 10

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

False

True

5 / 10

5. 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;

6 / 10

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

SAFE

ACID

HIPPA

SOC2

7 / 10

7. The SQL standard specifies three isolation levels?

True

False

8 / 10

8. non-repeatable read anomaly occurs when?

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 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 once and modifies this row and commits the change.

9 / 10

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

Serializable

Read Committed

Read Uncommitted

Repeatable Read

10 / 10

10. A phantom read anomaly occurs when?

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.

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.

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. The page header is located in the highest address?

True

False

2 / 10

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

False

True

3 / 10

3. CLOG contains how many bits for each transaction?

4 / 10

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

COMMIT

CREATE

DELETE

INSERT

5 / 10

5. The page header stores checksum and the sizes of the other parts of the page?

False

True

6 / 10

6. Information about subtransactions is stored under?

PGDATA/subtrans

PGDATA/pg_xid

PGDATA/pg_min

PGDATA/pg_subtrans

7 / 10

7. Which 2 items does a Virtual XID consist of?

backend process ID

sequential number

xmin

checksum

8 / 10

8. CLOG files are stored in which directory?

PGDATA/pg_xact

PGDATA/pg_clog

PGDATA/clog

PGDATA/pg_commit

9 / 10

9. Tuples can also be referred to as columns?

False

True

10 / 10

10. Page free space can often become fragmented?

True

False

Your score is

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