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 purpose of the public schema?

restricted schema for postgres internal usage only

no such schema

schema used for heterogeneous replication

default schema for user objects

2 / 20

2. What is the purpose of the postgres database?

a template for all the other database

regular database that you can use at your discretion

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

No such database

3 / 20

3. Postgres uses a thread based process model?

False

True

4 / 20

4. Some System Catalog tables are common to all databases in the cluster?

True

False

5 / 20

5. What is the name of the 2 default tablespaces created after initialization?

choose 2

pg_temp

pg_global

pg_default

pg_tablespace

6 / 20

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

wal space map

free space map

used space map

vacuum space map

7 / 20

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

pg_catalog

pg_system

pg_class

pg_tables

8 / 20

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

False

True

9 / 20

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

True

False

10 / 20

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

True

False

11 / 20

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

True

False

12 / 20

12. Which of below are predefined schemas?

choose 2

pg_catalog

postgres

system

public

13 / 20

13. What is the purpose of wal writer?

flushes dirty pages to disk.

collects usage statistics for the instance.

writes WAL entries to disk

executes checkpoints

14 / 20

14. What is the point of the pg_global tablespace?

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

stores temporary tables that are common to the whole cluster

15 / 20

15. When PostgreSQL is running what can it be referred to as?

Choose 2 option

Aurora

Postgres Server

Instance

Quorum

16 / 20

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

True

False

17 / 20

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

18 / 20

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

pg_symlinks

pg_tblspc

pg_tabspace

pg_tablespace

19 / 20

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

oid

oid#

obj#

obj

20 / 20

20. What is the purpose of the visibility map?

shows referential relationships for tables

provides the data decryption key

provides an audit trail for the database

shows a page to be vacuumed or frozen

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

Select more than 1 answer below:

Use a single SQL operator

Apply explicit locks

Issues a rollback after the commit to satisfy repeatable read.

Replace procedural code with declarative one.

2 / 10

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

False

True

3 / 10

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

False

True

4 / 10

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

Repeatable Read

Read Uncommitted

Serializable

Read Committed

5 / 10

5. Which of the below would best describe a dirty read?

reading data direct from memory using pg_dirt

a session being able to see commited data altered by another session

reading the data directly from file using a text editor such as vi or notepad

a session being able to see uncommited data altered by another session

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 and commits the change.

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 issue a rollback.

8 / 10

8. 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.

9 / 10

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

ALTER SYSTEM SET ISO=REPEATABLE_READ;

CREATE EXTENSTION REPEATABLE_READ;

SET ISO=REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

10 / 10

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

choose 3

Serializable

Repeatable Read

Read Committed

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

True

False

2 / 10

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

pg_current_commit_id()

pg_current_id()

pg_current_xact_id()

pg_current_xmin_id()

3 / 10

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

choose 2

flashback block

undo segment

page header

free space

4 / 10

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

True

False

5 / 10

5. Information about subtransactions is stored under?

PGDATA/pg_min

PGDATA/pg_subtrans

PGDATA/subtrans

PGDATA/pg_xid

6 / 10

6. If a transaction aborts, all page changes are reverted(rolled back) in place?

True

False

7 / 10

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

COMMIT

DELETE

INSERT

CREATE

8 / 10

8. What does an Item Pointer contain?

choose 3

tuple offset from the start of the page

tuple status

tuple xid

tuple length

9 / 10

9. indexes do not use row versioning?

False

True

10 / 10

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

False

True

Your score is

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