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

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

PGBASE

PGTIPS

PGDATA

PGCORE

2 / 20

A schema can belong to more than one database?

False

True

3 / 20

pg_catalog schema is used to store system catalog tables?

False

True

4 / 20

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

pg_system

pg_catalog

pg_class

pg_tables

5 / 20

Postgres uses a thread based process model?

False

True

6 / 20

Postgres server spawns a new backend session for each connection?

False

True

7 / 20

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

System Catalog

Sysaux Catalog

Sysasm Catalog

Sys Catalog

8 / 20

The information_schema schema provides information on Postgres release notes?

True

False

9 / 20

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

True

False

10 / 20

System Catalog tables begin with which prefix?

dba_

cat_

pg_

sys_

11 / 20

What is the point of the pg_global tablespace?

stores temporary tables that are common to the whole cluster

stores WAL logs used for global replication

stores user tables that are common to the whole cluster

stores system catalog objects that are common to the whole cluster

12 / 20

What is the purpose of wal writer?

collects usage statistics for the instance.

writes WAL entries to disk

flushes dirty pages to disk.

executes checkpoints

13 / 20

Each tablespaces can only be assigned for use by one database

True

False

14 / 20

Which fork contains the actual table data?

table map

free space map

visiblilty map

Main fork

15 / 20

What is the process first launched at server start?

init

postgres

pginit

postman

16 / 20

Tablespaces are used to define physical data layout?

True

False

17 / 20

Which fork keeps track of available space within pages?

used space map

wal space map

free space map

vacuum space map

18 / 20

To be able to restore data consistency, Postgres maintains

undo segments (UNDO)

rollback segments (RBS)

write-ahead log (WAL)

online redo logs (ORL)

19 / 20

Postgres by default has built in connection pooling abilities?

False

True

20 / 20

Each Database has its own System Catalog?

True

False

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

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

False

True

2 / 10

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.

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

3 / 10

The SQL standard specifies three isolation levels?

True

False

4 / 10

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

Read Uncommitted

Repeatable Read

Read Committed

Serializable

5 / 10

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

False

True

6 / 10

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

HIPPA

ACID

SAFE

SOC2

7 / 10

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

Select more than 1 answer below:

Apply explicit locks

Use a single SQL operator

Replace procedural code with declarative one.

Issues a rollback after the commit to satisfy repeatable read.

8 / 10

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

True

False

9 / 10

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 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.

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

10 / 10

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

ALTER SYSTEM SET ISO=REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

SET ISO=REPEATABLE_READ;

CREATE EXTENSTION 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

When a transaction is committed Postgres uses a special <replace with answer> structure?

commit log

transaction log

redo log

archive log

2 / 10

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

pageinspect

pagedetect

pagesize

pageheadinfo

3 / 10

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

False

True

4 / 10

Information about subtransactions is stored under?

PGDATA/pg_min

PGDATA/subtrans

PGDATA/pg_subtrans

PGDATA/pg_xid

5 / 10

The page header is located in the highest address?

False

True

6 / 10

If a transaction aborts, all page changes are reverted(rolled back) in place?

False

True

7 / 10

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

True

False

8 / 10

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

False

True

9 / 10

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

pg_current_commit_id()

pg_current_id()

pg_current_xmin_id()

pg_current_xact_id()

10 / 10

Which 2 items does a Virtual XID consist of?

sequential number

xmin

checksum

backend process ID

Your score is

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