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 default standard size for a fork file?

5GB

5MB

1MB

1GB

2 / 20

2. What is the purpose of the visibility map?

shows a page to be vacuumed or frozen

provides the data decryption key

provides an audit trail for the database

shows referential relationships for tables

3 / 20

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

table map

visiblilty map

free space map

Main fork

4 / 20

4. What is the purpose of autovacuum?

Removes stale data from tables and indexes

Performs a backup of WAL logs

Deletes old logs and traces on disk

Rebuilds indexes with b level greater than 2

5 / 20

5. Users should not modify the template0 database

False

True

6 / 20

6. Who is the Author of the Postgres 14 Internals book?

Paul Sammy

Egor Rogov

Dan Brown

Sam Altman

7 / 20

7. What is the point of the pg_global tablespace?

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

stores WAL logs used for global replication

8 / 20

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

True

False

9 / 20

9. What is the purpose of the template1 database?

a template for all the other databases

regular database that you can use at your discretion

No such database

database used for temporary tables

10 / 20

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

False

True

11 / 20

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

pg_tablespace

pg_symlinks

pg_tblspc

pg_tabspace

12 / 20

12. A Postgres cluster consists of 2 or more physical servers accessing one Postgres Instance?

False

True

13 / 20

13. To understand each other, a client and a server must use one and the same interfacing protocol?

True

False

14 / 20

14. Which of below are predefined schemas?

choose 3

pg_temp

pg_toast

information_schema

pg_schema

15 / 20

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

True

False

16 / 20

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

True

False

17 / 20

17. System Catalog tables begin with which prefix?

dba_

cat_

sys_

pg_

18 / 20

18. What is the purpose of the postgres database?

regular database that you can use at your discretion

No such database

a template for all the other database

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

19 / 20

19. Files are logically split into pages?

False

True

20 / 20

20. Each Database has its own System Catalog?

False

True

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

Serializable

Repeatable Read

Read Committed

Read Uncommitted

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 issue a rollback.

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 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.

4 / 10

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

False

True

5 / 10

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

choose 3

Read Uncommitted

Read Committed

Repeatable Read

Serializable

6 / 10

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

Select more than 1 answer below:

Apply explicit locks

Issues a rollback after the commit to satisfy repeatable read.

Replace procedural code with declarative one.

Use a single SQL operator

7 / 10

7. What is the default Isolation Level?

Read Uncommitted

Repeatable Read

Read Committed

Serializable

8 / 10

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

False

True

9 / 10

9. Which of the below are valid Isolations Levels?

choose 2

Rollback Read

Read Committed

Serializable

Random Scatter

10 / 10

10. 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 transactions issues a commit, then a rollback to restore data to its original value

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.

A transactions inserts a null value into a not null columns and commits

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. What does an Item Pointer contain?

choose 3

tuple status

tuple xid

tuple length

tuple offset from the start of the page

2 / 10

2. In Postgres, tables are often referred to as which of the below?

view

clog

dump

heap

3 / 10

3. CLOG files are stored in which directory?

PGDATA/pg_xact

PGDATA/pg_clog

PGDATA/clog

PGDATA/pg_commit

4 / 10

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

False

True

5 / 10

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

pg_current_xact_id()

pg_current_id()

pg_current_xmin_id()

pg_current_commit_id()

6 / 10

6. Page free space can often become fragmented?

False

True

7 / 10

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

True

False

8 / 10

8. The page header stores checksum and the sizes of the other parts of the page?

False

True

9 / 10

9. at any one time Postgres can have several versions of a row?

False

True

10 / 10

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

True

False

Your score is

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