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 the process first launched at server start?

init

postgres

postman

pginit

2 / 20

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

True

False

3 / 20

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

5MB

5GB

1GB

1MB

4 / 20

4. The information_schema schema provides information on Postgres release notes?

True

False

5 / 20

5. System Catalog tables begin with which prefix?

pg_

sys_

cat_

dba_

6 / 20

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

visiblilty map

table map

Main fork

free space map

7 / 20

7. What command is used to create the Postgres cluster?

Initialize

StartNewPG

CreatePGC

CreateCluster

8 / 20

8. Which of below are predefined schemas?

choose 3

information_schema

pg_temp

pg_toast

pg_schema

9 / 20

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

Search Path

Directory Path

Schema Path

Access Path

10 / 20

10. TOAST tables reside in a seperate schema?

False

True

11 / 20

11. Postgres uses a thread based process model?

False

True

12 / 20

12. What is the name of the system catalog table for relations?

pg_system

pg_catalog

pg_class

pg_tables

13 / 20

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

14 / 20

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

pg_tablespace

pg_symlinks

pg_tabspace

pg_tblspc

15 / 20

15. What column in system catalogs servers as the Primary Key

oid#

obj#

obj

oid

16 / 20

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

True

False

17 / 20

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

PGDATA

PGTIPS

PGBASE

PGCORE

18 / 20

18. What is the purpose of the postgres database?

regular database that you can use at your discretion

No such database

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

a template for all the other database

19 / 20

19. What is the purpose of the template1 database?

database used for temporary tables

No such database

regular database that you can use at your discretion

a template for all the other databases

20 / 20

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

write-ahead log (WAL)

undo segments (UNDO)

rollback segments (RBS)

online redo logs (ORL)

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. 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 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

2 / 10

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

Select more than 1 answer below:

Replace procedural code with declarative one.

Use a single SQL operator

Apply explicit locks

Issues a rollback after the commit to satisfy repeatable read.

3 / 10

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

CREATE EXTENSTION REPEATABLE_READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

SET ISO=REPEATABLE_READ;

4 / 10

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

False

True

5 / 10

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

False

True

6 / 10

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

False

True

7 / 10

7. 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.

8 / 10

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

False

True

9 / 10

9. Which parameters sets the database default isolation level?

transaction_isolation_level

default_transaction_isolation

active_transaction_isolation

default_isolation_level

10 / 10

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

Repeatable Read

Read Uncommitted

Read Committed

Serializable

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

True

False

2 / 10

2. Page free space can often become fragmented?

False

True

3 / 10

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

INSERT

COMMIT

DELETE

CREATE

4 / 10

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

False

True

5 / 10

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

True

False

6 / 10

6. Rows of TOAST tables are handled in such a way that they are never update?

False

True

7 / 10

7. indexes do not use row versioning?

False

True

8 / 10

8. Tuples can also be referred to as columns?

False

True

9 / 10

9. Information about subtransactions is stored under?

PGDATA/pg_subtrans

PGDATA/pg_min

PGDATA/pg_xid

PGDATA/subtrans

10 / 10

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

pagesize

pageinspect

pageheadinfo

pagedetect

Your score is

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