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

True

False

2 / 20

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

True

False

3 / 20

3. Which fork contains the actual table data?

free space map

Main fork

visiblilty map

table map

4 / 20

4. Which of the below objects can be referred to as relations?

choose 3

tables

triggers

indexes

sequences

5 / 20

5. Tablespaces are used to define physical data layout?

True

False

6 / 20

6. Which of below are predefined schemas?

choose 2

postgres

pg_catalog

system

public

7 / 20

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

True

False

8 / 20

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

Search Path

Access Path

Schema Path

Directory Path

9 / 20

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

BREAD

BAKE

GROW

TOAST

10 / 20

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

Dan Brown

Sam Altman

Paul Sammy

Egor Rogov

11 / 20

11. What is the purpose of the public schema?

default schema for user objects

restricted schema for postgres internal usage only

schema used for heterogeneous replication

no such schema

12 / 20

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

Sysaux Catalog

System Catalog

Sys Catalog

Sysasm Catalog

13 / 20

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

pg_tblspc

pg_symlinks

pg_tabspace

pg_tablespace

14 / 20

14. What is the purpose of wal writer?

collects usage statistics for the instance.

writes WAL entries to disk

flushes dirty pages to disk.

executes checkpoints

15 / 20

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

oid#

obj#

obj

oid

16 / 20

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

True

False

17 / 20

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

18 / 20

18. What is the purpose of the template0 database?

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

No such database

Useful for creating development schemas

Useful for Postgres support Services to debug issues

19 / 20

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

pg_tables

pg_class

pg_system

pg_catalog

20 / 20

20. What is the purpose of autovacuum?

Deletes old logs and traces on disk

Removes stale data from tables and indexes

Rebuilds indexes with b level greater than 2

Performs a backup of WAL logs

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

choose 3

Repeatable Read

Read Committed

Read Uncommitted

Serializable

2 / 10

2. 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.

3 / 10

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

Select more than 1 answer below:

Issues a rollback after the commit to satisfy repeatable read.

Replace procedural code with declarative one.

Apply explicit locks

Use a single SQL operator

4 / 10

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

False

True

5 / 10

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

Repeatable Read

Serializable

Read Committed

Read Uncommitted

6 / 10

6. What is the default Isolation Level?

Read Uncommitted

Serializable

Read Committed

Repeatable Read

7 / 10

7. Which of the below are valid Isolations Levels?

choose 2

Read Committed

Rollback Read

Serializable

Random Scatter

8 / 10

8. Which parameters sets the database default isolation level?

transaction_isolation_level

default_transaction_isolation

default_isolation_level

active_transaction_isolation

9 / 10

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

True

False

10 / 10

10. 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, 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.

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

False

True

2 / 10

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

choose 2

free space

flashback block

page header

undo segment

3 / 10

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

False

True

4 / 10

4. Tuples can also be referred to as columns?

True

False

5 / 10

5. CLOG Pages are never cached in memory?

True

False

6 / 10

6. CLOG files are stored in which directory?

PGDATA/pg_xact

PGDATA/clog

PGDATA/pg_clog

PGDATA/pg_commit

7 / 10

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

clog

heap

dump

view

8 / 10

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

COMMIT

CREATE

INSERT

DELETE

9 / 10

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

False

True

10 / 10

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

pg_current_commit_id()

pg_current_xmin_id()

pg_current_id()

pg_current_xact_id()

Your score is

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