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 name of the mechanism used to store a row bigger than a page size?

TOAST

BREAD

GROW

BAKE

2 / 20

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

Egor Rogov

Dan Brown

Sam Altman

Paul Sammy

3 / 20

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

True

False

4 / 20

4. To be able to restore data consistency, Postgres maintains

write-ahead log (WAL)

online redo logs (ORL)

undo segments (UNDO)

rollback segments (RBS)

5 / 20

5. Each Database has its own System Catalog?

True

False

6 / 20

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

obj

oid#

obj#

oid

7 / 20

7. What is the purpose of wal writer?

collects usage statistics for the instance.

executes checkpoints

flushes dirty pages to disk.

writes WAL entries to disk

8 / 20

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

pg_tables

pg_catalog

pg_system

pg_class

9 / 20

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

Directory Path

Search Path

Access Path

Schema Path

10 / 20

10. 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 WAL logs used for global replication

stores temporary tables that are common to the whole cluster

11 / 20

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

False

True

12 / 20

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

True

False

13 / 20

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

True

False

14 / 20

14. The default Page size is 2k?

True

False

15 / 20

15. What is a schema?

This is the same as a user in Postgres

The name used to refer to a super user account

Namespace that store all objects of a database

A memory area used to cache data from LRU chains

16 / 20

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

False

True

17 / 20

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

free space map

visiblilty map

Main fork

table map

18 / 20

18. What is the purpose of autovacuum?

Rebuilds indexes with b level greater than 2

Deletes old logs and traces on disk

Performs a backup of WAL logs

Removes stale data from tables and indexes

19 / 20

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

True

False

20 / 20

20. What is the purpose of the postgres database?

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

No such database

a template for all the other database

regular database that you can use at your discretion

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 is the acronym used for the attributes that ensure Data consistency, integrity and durability?

SAFE

HIPPA

SOC2

ACID

2 / 10

2. 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.

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 adds some other rows satisfying this condition and commits.

3 / 10

3. 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 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 twice, another transaction modifies this row between these reads issue a rollback.

4 / 10

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

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?

True

False

7 / 10

7. Which of the below are valid Isolations Levels?

choose 2

Read Committed

Random Scatter

Rollback Read

Serializable

8 / 10

8. 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

Issues a rollback after the commit to satisfy repeatable read.

Apply explicit locks

Replace procedural code with declarative one.

9 / 10

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

Repeatable Read

Read Uncommitted

Serializable

Read Committed

10 / 10

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

True

False

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

True

False

2 / 10

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

heap XID

virtual XID

temporary XID

magic XID

3 / 10

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

False

True

4 / 10

4. CLOG files are stored in which directory?

PGDATA/pg_xact

PGDATA/pg_commit

PGDATA/pg_clog

PGDATA/clog

5 / 10

5. Tuples can also be referred to as columns?

True

False

6 / 10

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

backend process ID

checksum

xmin

sequential number

7 / 10

7. Information about subtransactions is stored under?

PGDATA/subtrans

PGDATA/pg_xid

PGDATA/pg_min

PGDATA/pg_subtrans

8 / 10

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

True

False

9 / 10

9. CLOG contains how many bits for each transaction?

10 / 10

10. Page header sizes can be easily displayed using the <choose from answers> extension

pagesize

pageheadinfo

pageinspect

pagedetect

Your score is

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