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 purpose of wal writer?

collects usage statistics for the instance.

writes WAL entries to disk

executes checkpoints

flushes dirty pages to disk.

2 / 20

2. What is the purpose of autovacuum?

Performs a backup of WAL logs

Deletes old logs and traces on disk

Removes stale data from tables and indexes

Rebuilds indexes with b level greater than 2

3 / 20

3. What is the purpose of the postgres 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

a template for all the other database

4 / 20

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

True

False

5 / 20

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

5GB

5MB

1GB

1MB

6 / 20

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

True

False

7 / 20

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

8 / 20

8. What is a schema?

The name used to refer to a super user account

This is the same as a user in Postgres

A memory area used to cache data from LRU chains

Namespace that store all objects of a database

9 / 20

9. Which fork is specific for unlogged tables?

Main fork

Initialization fork

visiblilty map

free space map

10 / 20

10. Each Database has its own System Catalog?

False

True

11 / 20

11. The default Page size is 2k?

False

True

12 / 20

12. What is the purpose of the visibility map?

shows a page to be vacuumed or frozen

provides the data decryption key

provides an audit trail for the database

shows referential relationships for tables

13 / 20

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

StartNewPG

CreatePGC

CreateCluster

Initialize

14 / 20

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

free space map

wal space map

used space map

vacuum space map

15 / 20

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

True

False

16 / 20

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

17 / 20

17. Which fork contains the actual table data?

table map

free space map

visiblilty map

Main fork

18 / 20

18. It is the postmasters job to listener for incoming connections?

False

True

19 / 20

19. Tablespaces are used to define physical data layout?

True

False

20 / 20

20. What is the purpose of the public schema?

restricted schema for postgres internal usage only

no such schema

default schema for user objects

schema used for heterogeneous replication

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?

SOC2

SAFE

HIPPA

ACID

2 / 10

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

False

True

3 / 10

3. What is the default Isolation Level?

Repeatable Read

Serializable

Read Uncommitted

Read Committed

4 / 10

4. 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.

5 / 10

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

Select more than 1 answer below:

Apply explicit locks

Issues a rollback after the commit to satisfy repeatable read.

Replace procedural code with declarative one.

Use a single SQL operator

6 / 10

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

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

reading the data directly from file using a text editor such as vi or notepad

7 / 10

7. Which parameters sets the database default isolation level?

default_transaction_isolation

transaction_isolation_level

default_isolation_level

active_transaction_isolation

8 / 10

8. 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 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.

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

9 / 10

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

choose 3

Read Uncommitted

Repeatable Read

Serializable

Read Committed

10 / 10

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

Repeatable Read

Read Committed

Read Uncommitted

Serializable

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

pagedetect

pageheadinfo

pageinspect

pagesize

2 / 10

2. CLOG contains how many bits for each transaction?

3 / 10

3. Page free space can often become fragmented?

True

False

4 / 10

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

pg_current_xact_id()

pg_current_xmin_id()

pg_current_commit_id()

pg_current_id()

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

False

True

7 / 10

7. What does an Item Pointer contain?

choose 3

tuple xid

tuple length

tuple offset from the start of the page

tuple status

8 / 10

8. CLOG files are stored in which directory?

PGDATA/pg_clog

PGDATA/clog

PGDATA/pg_xact

PGDATA/pg_commit

9 / 10

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

heap XID

magic XID

virtual XID

temporary XID

10 / 10

10. Which 2 of the below represent transaction IDs used for row versioning?

xtime

xmax

xmin

xid

Your score is

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