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. Each Database has its own System Catalog?

False

True

2 / 20

2. What is the purpose of the template0 database?

No such database

Useful for Postgres support Services to debug issues

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

Useful for creating development schemas

3 / 20

3. Tablespaces are used to define physical data layout?

True

False

4 / 20

4. What is the purpose of autovacuum?

Deletes old logs and traces on disk

Rebuilds indexes with b level greater than 2

Performs a backup of WAL logs

Removes stale data from tables and indexes

5 / 20

5. The default Page size is 2k?

True

False

6 / 20

6. Files are logically split into pages?

True

False

7 / 20

7. What is another name for the postgres process?

aurora

postmanager

masterprocess

postmaster

8 / 20

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

False

True

9 / 20

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

True

False

10 / 20

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

BREAD

BAKE

TOAST

GROW

11 / 20

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

False

True

12 / 20

12. What is the purpose of the public schema?

restricted schema for postgres internal usage only

default schema for user objects

schema used for heterogeneous replication

no such schema

13 / 20

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

14 / 20

14. Postgres by default has built in connection pooling abilities?

False

True

15 / 20

15. What is the purpose of the visibility map?

provides an audit trail for the database

shows a page to be vacuumed or frozen

shows referential relationships for tables

provides the data decryption key

16 / 20

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

rollback segments (RBS)

undo segments (UNDO)

online redo logs (ORL)

write-ahead log (WAL)

17 / 20

17. Postgres uses a thread based process model?

True

False

18 / 20

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

False

True

19 / 20

19. Which fork is specific for unlogged tables?

Main fork

free space map

Initialization fork

visiblilty map

20 / 20

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

oid

obj#

obj

oid#

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

True

False

2 / 10

2. 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 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.

A transaction reads one and the same row twice, another transaction modifies this row between these reads issue a rollback.

3 / 10

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

Read Uncommitted

Read Committed

Serializable

Repeatable Read

4 / 10

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

choose 3

Read Uncommitted

Read Committed

Serializable

Repeatable Read

5 / 10

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

SET ISO=REPEATABLE_READ;

CREATE EXTENSTION REPEATABLE_READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

6 / 10

6. 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

7 / 10

7. 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.

8 / 10

8. The SQL standard specifies three isolation levels?

True

False

9 / 10

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

False

True

10 / 10

10. What is the default Isolation Level?

Read Committed

Serializable

Repeatable Read

Read Uncommitted

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. Tuples can also be referred to as columns?

True

False

2 / 10

2. What does an Item Pointer contain?

choose 3

tuple length

tuple offset from the start of the page

tuple status

tuple xid

3 / 10

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

True

False

4 / 10

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

xmas

xmin

xid

xmax

5 / 10

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

pg_current_id()

pg_current_commit_id()

pg_current_xmin_id()

pg_current_xact_id()

6 / 10

6. When a transaction is committed Postgres uses a special <replace with answer> structure?

transaction log

commit log

archive log

redo log

7 / 10

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

False

True

8 / 10

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

False

True

9 / 10

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

pagedetect

pagesize

pageinspect

pageheadinfo

10 / 10

10. Each page has a layer that usually consists of?

choose 2

page header

undo segment

flashback block

free space

Your score is

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