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. Which fork is specific for unlogged tables?

Initialization fork

visiblilty map

Main fork

free space map

2 / 20

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

True

False

3 / 20

3. 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

4 / 20

4. Which 3 databases exist directly after cluster initialization?

choose 3 options

sysaux

template0

postgres

template1

5 / 20

5. A schema can belong to more than one database?

True

False

6 / 20

6. Which of below are predefined schemas?

choose 3

pg_toast

pg_temp

information_schema

pg_schema

7 / 20

7. Files are logically split into pages?

False

True

8 / 20

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

9 / 20

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

choose 3

tables

sequences

indexes

triggers

10 / 20

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

True

False

11 / 20

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

table map

Main fork

free space map

visiblilty map

12 / 20

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

True

False

13 / 20

13. 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

14 / 20

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

PGCORE

PGBASE

PGTIPS

PGDATA

15 / 20

15. The default Page size is 2k?

False

True

16 / 20

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

pg_tabspace

pg_tablespace

pg_tblspc

pg_symlinks

17 / 20

17. Each tablespaces can only be assigned for use by one database

False

True

18 / 20

18. What is the purpose of the postgres database?

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

No such database

regular database that you can use at your discretion

a template for all the other database

19 / 20

19. What is the purpose of the template1 database?

No such database

database used for temporary tables

regular database that you can use at your discretion

a template for all the other databases

20 / 20

20. Which fork keeps track of available space within pages?

vacuum space map

used space map

free space map

wal space map

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 once and modifies this row 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 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.

2 / 10

2. The SQL standard specifies three isolation levels?

True

False

3 / 10

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

BEGIN ISOLATION LEVEL REPEATABLE READ;

SET ISO=REPEATABLE_READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

CREATE EXTENSTION REPEATABLE_READ;

4 / 10

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

True

False

5 / 10

5. What is the default Isolation Level?

Read Committed

Repeatable Read

Read Uncommitted

Serializable

6 / 10

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

Read Uncommitted

Read Committed

Repeatable Read

Serializable

7 / 10

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

False

True

8 / 10

8. Which parameters sets the database default isolation level?

transaction_isolation_level

default_transaction_isolation

active_transaction_isolation

default_isolation_level

9 / 10

9. 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 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

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.

10 / 10

10. Which of the below are valid Isolations Levels?

choose 2

Rollback Read

Read Committed

Serializable

Random Scatter

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. CLOG contains how many bits for each transaction?

2 / 10

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

pagedetect

pageheadinfo

pageinspect

pagesize

3 / 10

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

INSERT

DELETE

CREATE

COMMIT

4 / 10

4. Information about subtransactions is stored under?

PGDATA/pg_min

PGDATA/pg_subtrans

PGDATA/pg_xid

PGDATA/subtrans

5 / 10

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

True

False

6 / 10

6. CLOG files are stored in which directory?

PGDATA/pg_clog

PGDATA/pg_xact

PGDATA/clog

PGDATA/pg_commit

7 / 10

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

pg_current_xact_id()

pg_current_commit_id()

pg_current_id()

pg_current_xmin_id()

8 / 10

8. A page along with its tuples is read into the buffer cache with compression transformations to enhance cache efficiency?

True

False

9 / 10

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

backend process ID

xmin

checksum

sequential number

10 / 10

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

False

True

Your score is

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