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

True

False

2 / 20

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

False

True

3 / 20

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

CreateCluster

Initialize

CreatePGC

StartNewPG

4 / 20

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

Choose 2 option

Quorum

Aurora

Postgres Server

Instance

5 / 20

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

True

False

6 / 20

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

False

True

7 / 20

7. Which of below are predefined schemas?

choose 2

public

postgres

pg_catalog

system

8 / 20

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

GROW

TOAST

BAKE

BREAD

9 / 20

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

10 / 20

10. What is the point of the pg_global tablespace?

stores user tables that are common to the whole cluster

stores system catalog objects that are common to the whole cluster

stores WAL logs used for global replication

stores temporary tables that are common to the whole cluster

11 / 20

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

visiblilty map

table map

free space map

Main fork

12 / 20

12. Users should not modify the template0 database

True

False

13 / 20

13. What is the purpose of the template1 database?

a template for all the other databases

No such database

regular database that you can use at your discretion

database used for temporary tables

14 / 20

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

False

True

15 / 20

15. What is the purpose of autovacuum?

Removes stale data from tables and indexes

Deletes old logs and traces on disk

Performs a backup of WAL logs

Rebuilds indexes with b level greater than 2

16 / 20

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

True

False

17 / 20

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

True

False

18 / 20

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

False

True

19 / 20

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

False

True

20 / 20

20. What is the purpose of the visibility map?

provides an audit trail for the database

shows referential relationships for tables

provides the data decryption key

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. non-repeatable read anomaly occurs when?

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.

A transaction reads one and the same row once and modifies this row and commits the change.

2 / 10

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

choose 3

Serializable

Read Uncommitted

Read Committed

Repeatable Read

3 / 10

3. Which of the below are valid Isolations Levels?

choose 2

Random Scatter

Rollback Read

Read Committed

Serializable

4 / 10

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

Serializable

Read Uncommitted

Repeatable Read

Read Committed

5 / 10

5. Which parameters sets the database default isolation level?

default_isolation_level

active_transaction_isolation

transaction_isolation_level

default_transaction_isolation

6 / 10

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

False

True

7 / 10

7. 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.

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

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

True

False

9 / 10

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

False

True

10 / 10

10. 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

Replace procedural code with declarative one.

Issues a rollback after the commit to satisfy repeatable read.

Apply explicit locks

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

True

False

2 / 10

2. CLOG files are stored in which directory?

PGDATA/clog

PGDATA/pg_xact

PGDATA/pg_clog

PGDATA/pg_commit

3 / 10

3. UPDATE can be regarded as which 2 separate operations?

MERGE

INSERT

COMMIT

DELETE

4 / 10

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

True

False

5 / 10

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

False

True

6 / 10

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

pg_current_id()

pg_current_commit_id()

pg_current_xact_id()

pg_current_xmin_id()

7 / 10

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

xmas

xmax

xid

xmin

8 / 10

8. CLOG contains how many bits for each transaction?

9 / 10

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

True

False

10 / 10

10. Information about subtransactions is stored under?

PGDATA/pg_subtrans

PGDATA/subtrans

PGDATA/pg_xid

PGDATA/pg_min

Your score is

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