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. Tablespaces are used to define physical data layout?

False

True

2 / 20

2. What is the purpose of the postgres database?

a template for all the other database

regular database that you can use at your discretion

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

No such database

3 / 20

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

oid#

obj

oid

obj#

4 / 20

4. TOAST tables reside in a seperate schema?

False

True

5 / 20

5. What is the purpose of the visibility map?

provides an audit trail for the database

shows a page to be vacuumed or frozen

shows referential relationships for tables

provides the data decryption key

6 / 20

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

visiblilty map

table map

Main fork

free space map

7 / 20

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

False

True

8 / 20

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

online redo logs (ORL)

undo segments (UNDO)

write-ahead log (WAL)

rollback segments (RBS)

9 / 20

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

pg_class

pg_tables

pg_catalog

pg_system

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

True

False

12 / 20

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

True

False

13 / 20

13. What is the purpose of wal writer?

collects usage statistics for the instance.

executes checkpoints

writes WAL entries to disk

flushes dirty pages to disk.

14 / 20

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

15 / 20

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

True

False

16 / 20

16. System Catalog tables begin with which prefix?

pg_

dba_

sys_

cat_

17 / 20

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

False

True

18 / 20

18. Which fork is specific for unlogged tables?

Initialization fork

visiblilty map

Main fork

free space map

19 / 20

19. What is the name of the 2 default tablespaces created after initialization?

choose 2

pg_default

pg_global

pg_tablespace

pg_temp

20 / 20

20. What is the name of the directory that contains the files related to the Postgres cluster?

PGDATA

PGBASE

PGTIPS

PGCORE

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 parameters sets the database default isolation level?

active_transaction_isolation

transaction_isolation_level

default_transaction_isolation

default_isolation_level

3 / 10

3. Which of the below are valid Isolations Levels?

choose 2

Random Scatter

Serializable

Read Committed

Rollback Read

4 / 10

4. 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 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 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

5 / 10

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

choose 3

Repeatable Read

Serializable

Read Uncommitted

Read Committed

6 / 10

6. 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 issue a rollback.

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.

7 / 10

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

False

True

8 / 10

8. What is the default Isolation Level?

Serializable

Repeatable Read

Read Committed

Read Uncommitted

9 / 10

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

False

True

10 / 10

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

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

True

False

2 / 10

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

choose 2

free space

undo segment

page header

flashback block

3 / 10

3. Page free space can often become fragmented?

True

False

4 / 10

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

pagedetect

pageheadinfo

pagesize

pageinspect

5 / 10

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

True

False

6 / 10

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

True

False

7 / 10

7. CLOG Pages are never cached in memory?

True

False

8 / 10

8. Information about subtransactions is stored under?

PGDATA/pg_min

PGDATA/subtrans

PGDATA/pg_xid

PGDATA/pg_subtrans

9 / 10

9. The page Special Space is located at the start of the page with highest address

True

False

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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