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

True

False

2 / 20

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

CreatePGC

Initialize

CreateCluster

StartNewPG

3 / 20

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

Sysaux Catalog

Sys Catalog

System Catalog

Sysasm Catalog

4 / 20

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

False

True

5 / 20

5. Which of below are predefined schemas?

choose 2

pg_catalog

public

postgres

system

6 / 20

6. What is another name for the postgres process?

aurora

postmaster

postmanager

masterprocess

7 / 20

7. Files are logically split into pages?

True

False

8 / 20

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

pg_catalog

pg_tables

pg_system

pg_class

9 / 20

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

True

False

10 / 20

10. What is the purpose of the visibility map?

shows referential relationships for tables

shows a page to be vacuumed or frozen

provides the data decryption key

provides an audit trail for the database

11 / 20

11. 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

12 / 20

12. Which 3 databases exist directly after cluster initialization?

choose 3 options

template1

postgres

template0

sysaux

13 / 20

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

Egor Rogov

Paul Sammy

Sam Altman

Dan Brown

14 / 20

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

1GB

1MB

5MB

5GB

15 / 20

15. What is the purpose of autovacuum?

Deletes old logs and traces on disk

Rebuilds indexes with b level greater than 2

Removes stale data from tables and indexes

Performs a backup of WAL logs

16 / 20

16. What is the point of the pg_global tablespace?

stores WAL logs used for global replication

stores user tables that are common to the whole cluster

stores system catalog objects that are common to the whole cluster

stores temporary tables that are common to the whole cluster

17 / 20

17. What is the process first launched at server start?

pginit

init

postman

postgres

18 / 20

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

19 / 20

19. What is the purpose of the template0 database?

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

Useful for creating development schemas

Useful for Postgres support Services to debug issues

No such database

20 / 20

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

True

False

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

True

False

2 / 10

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

False

True

3 / 10

3. 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 transaction executes two identical queries returning a set of rows that satisfy a particular condition, while another transaction also queries this same data.

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

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

4 / 10

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

False

True

5 / 10

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

False

True

6 / 10

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

False

True

7 / 10

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

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

reading data direct from memory using pg_dirt

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

8 / 10

8. 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 twice, another transaction modifies this row between these reads 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.

9 / 10

9. Which parameters sets the database default isolation level?

default_transaction_isolation

active_transaction_isolation

default_isolation_level

transaction_isolation_level

10 / 10

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

Select more than 1 answer below:

Replace procedural code with declarative one.

Apply explicit locks

Use a single SQL operator

Issues a rollback after the commit to satisfy repeatable read.

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. UPDATE can be regarded as which 2 separate operations?

COMMIT

MERGE

INSERT

DELETE

2 / 10

2. Which 2 items does a Virtual XID consist of?

backend process ID

xmin

sequential number

checksum

3 / 10

3. CLOG contains how many bits for each transaction?

4 / 10

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

pg_current_commit_id()

pg_current_xmin_id()

pg_current_xact_id()

pg_current_id()

5 / 10

5. What does an Item Pointer contain?

choose 3

tuple length

tuple status

tuple xid

tuple offset from the start of the page

6 / 10

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

CREATE

INSERT

DELETE

COMMIT

7 / 10

7. a transaction containing a savepoint is will still be considered as only a single transaction?

False

True

8 / 10

8. CLOG Pages are never cached in memory?

True

False

9 / 10

9. status of a subtransaction is written into CLOG?

False

True

10 / 10

10. If a transaction is read only which kind of Transaction ID is it allocated?

temporary XID

magic XID

virtual XID

heap XID

Your score is

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