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

False

True

3 / 20

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

Initialize

CreateCluster

CreatePGC

StartNewPG

4 / 20

4. What is the purpose of wal writer?

writes WAL entries to disk

executes checkpoints

flushes dirty pages to disk.

collects usage statistics for the instance.

5 / 20

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

choose 3

indexes

triggers

tables

sequences

6 / 20

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

pg_tabspace

pg_tblspc

pg_symlinks

pg_tablespace

7 / 20

7. System Catalog tables begin with which prefix?

cat_

pg_

sys_

dba_

8 / 20

8. TOAST tables reside in a seperate schema?

True

False

9 / 20

9. Which fork keeps track of available space within pages?

used space map

wal space map

vacuum space map

free space map

10 / 20

10. What is the purpose of autovacuum?

Deletes old logs and traces on disk

Rebuilds indexes with b level greater than 2

Performs a backup of WAL logs

Removes stale data from tables and indexes

11 / 20

11. What is the point of the pg_global tablespace?

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

stores user tables that are common to the whole cluster

12 / 20

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

Sys Catalog

Sysaux Catalog

System Catalog

Sysasm Catalog

13 / 20

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

14 / 20

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

False

True

15 / 20

15. Which of below are predefined schemas?

choose 3

information_schema

pg_toast

pg_schema

pg_temp

16 / 20

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

17 / 20

17. Each Database has its own System Catalog?

True

False

18 / 20

18. Users should not modify the template0 database

True

False

19 / 20

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

True

False

20 / 20

20. Which of below are predefined schemas?

choose 2

public

pg_catalog

system

postgres

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. Which of the below are valid Isolations Levels?

choose 2

Serializable

Rollback Read

Read Committed

Random Scatter

2 / 10

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

True

False

3 / 10

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

choose 3

Read Committed

Serializable

Read Uncommitted

Repeatable Read

4 / 10

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

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

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

5 / 10

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

True

False

6 / 10

6. The SQL standard specifies three isolation levels?

False

True

7 / 10

7. 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 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.

8 / 10

8. non-repeatable read anomaly occurs when?

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.

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.

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. which of the below statements will start a transaction as Read Repeatable?

CREATE EXTENSTION REPEATABLE_READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

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

False

True

2 / 10

2. status of a subtransaction is written into CLOG?

True

False

3 / 10

3. CLOG contains how many bits for each transaction?

4 / 10

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

MERGE

INSERT

DELETE

COMMIT

5 / 10

5. The page header is located in the highest address?

False

True

6 / 10

6. Information about subtransactions is stored under?

PGDATA/pg_xid

PGDATA/pg_subtrans

PGDATA/subtrans

PGDATA/pg_min

7 / 10

7. CLOG Pages are never cached in memory?

True

False

8 / 10

8. index row headers like table row headers contain xmin and xmax fields?

True

False

9 / 10

9. psql provides a special mode that allows you to continue a transaction after a failure?

True

False

10 / 10

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

True

False

Your score is

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