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 name of the directory that contains the files related to the Postgres cluster?

PGBASE

PGCORE

PGDATA

PGTIPS

2 / 20

2. What is the purpose of the public schema?

no such schema

restricted schema for postgres internal usage only

default schema for user objects

schema used for heterogeneous replication

3 / 20

3. 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

4 / 20

4. Which 3 databases exist directly after cluster initialization?

choose 3 options

template0

template1

sysaux

postgres

5 / 20

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

Sys Catalog

Sysaux Catalog

Sysasm Catalog

System Catalog

6 / 20

6. What is the purpose of wal writer?

collects usage statistics for the instance.

writes WAL entries to disk

executes checkpoints

flushes dirty pages to disk.

7 / 20

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

pg_tabspace

pg_tblspc

pg_symlinks

pg_tablespace

8 / 20

8. Which fork contains the actual table data?

Main fork

visiblilty map

table map

free space map

9 / 20

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

Directory Path

Access Path

Search Path

Schema Path

10 / 20

10. What is the point of the pg_global tablespace?

stores temporary tables that are common to the whole cluster

stores WAL logs used for global replication

stores system catalog objects that are common to the whole cluster

stores user tables that are common to the whole cluster

11 / 20

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

1GB

5GB

1MB

5MB

12 / 20

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

CreateCluster

Initialize

StartNewPG

CreatePGC

13 / 20

13. Files are logically split into pages?

False

True

14 / 20

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

True

False

15 / 20

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

16 / 20

16. What is the purpose of the template1 database?

database used for temporary tables

regular database that you can use at your discretion

a template for all the other databases

No such database

17 / 20

17. Users should not modify the template0 database

True

False

18 / 20

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

False

True

19 / 20

19. What is another name for the postgres process?

postmaster

masterprocess

aurora

postmanager

20 / 20

20. Which of below are predefined schemas?

choose 2

public

pg_catalog

postgres

system

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

False

True

2 / 10

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

False

True

3 / 10

3. 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 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.

4 / 10

4. A phantom read anomaly occurs when?

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.

The same transactions issues a commit, then a rollback to restore data to its original value

5 / 10

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

Repeatable Read

Read Committed

Serializable

Read Uncommitted

6 / 10

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

True

False

7 / 10

7. The SQL standard specifies three isolation levels?

False

True

8 / 10

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

False

True

9 / 10

9. 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;

10 / 10

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

choose 3

Repeatable Read

Read Committed

Read Uncommitted

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?

False

True

2 / 10

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

False

True

3 / 10

3. CLOG contains how many bits for each transaction?

4 / 10

4. Postgres table physical data files are always cross compatible across platforms?

False

True

5 / 10

5. To identify different versions of one and the same row, PostgreSQL marks each of them with which two value?

xmax

xmas

xid

xmin

6 / 10

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

True

False

7 / 10

7. Page free space can often become fragmented?

False

True

8 / 10

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

pageheadinfo

pagedetect

pagesize

pageinspect

9 / 10

9. What does an Item Pointer contain?

choose 3

tuple status

tuple offset from the start of the page

tuple xid

tuple length

10 / 10

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

xmax

xmin

xid

xtime

Your score is

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