Always upgrade! There are hundreds of fixes between each PostgreSQL release, and an important number of them are security fixes! Logical replication allows making major upgrades with minimal downtime and feasible cons. This webinar covered: - PostgreSQL releases - Upgrade options - What is Pglogical? - Major upgrades

1. Online upgrade using
logical replication

2. 2
Slides and recording will be made available
Submit questions via Zoom – will be answering at end
Welcome – Housekeeping Items

3. Whoami?
florin.irion@enterprisedb.com

4. 4
Agenda
• PostgreSQL releases
•
•
• Upgrade options
• What is Pglogical
• Major upgrades

5. 5
Why
Upgrade? ● Security
● Features
● Dba/management
● Performance
● SQL standard

6. 6
Release
Cadence

7. 7
EOL

8. 8
About
Minor
Updates

9. 9
About
Major
Upgrades
●
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○
○ Pglogical extension

10. 10
About
Major
Upgrades
●
●
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●
○
○ Pglogical extension

11. 11
Pglogical

12. 12
Pglogical
vs
Logical
Replication

13. 13
Upgrading
with
pglogical

14. 14
What are we
missing by
using
PostgreSQL 9.5?
https://why-upgrade.depesz.com/

15. 15
Missing
Features
● Parallel Aggregates
● Parallel sequential scans
● Declarative partitioning
● SCRAM Authentication
● Just In Time (JIT) compilation
● Parallel creation of index
● Stored Procedures
● Reindex concurrently
● etc.

16. 16
Nomenclature
and
conventions
● Node -- Postgresql database instance
● Provider -- sending node
● Subscriber -- receiver node
● Replication Set -- rule
● Subscription -- one subscriber makes to the
provider.
● pg95 pg13 -- my hostnames

17. 17
Requirements
● Primary key
SELECT n.nspname as schema, c.relname as table
FROM
pg_class c
JOIN
pg_namespace n
ON n.oid = c.relnamespace
WHERE
c.relkind = 'r'
AND NOT EXISTS (SELECT 1 FROM pg_constraint con
WHERE con.conrelid = c.oid AND con.contype = 'p'
)
AND n.nspname <> ALL ( ARRAY [
'pg_catalog',
'sys',
'dbo',
'information_schema']);
schema | table
--------+-------
(0 rows)

18. 18
Requirements
● Table names
● Table schema
● Table definition
● Constraints
● Global objects
● UNLOGGED and TEMPORARY
● DDL
○ replicate_ddl_command()

19. 19
Installation
PostgreSQL 9.5:
PostgreSQL 13:

20. 20
Configuration Postgresql.conf
shared_preload_libraries = 'pglogical'
wal_level = 'logical'
max_worker_processes = 10
max_wal_senders = 10
max_replication_slots = 10

21. 21
Pg_hba.conf
Authentication

22. 22
Create
extension
and nodes
CREATE EXTENSION pglogical;
SELECT pglogical.create_node (
node_name: = 'provider1',
dsn: = 'host = pg95 port = 5432 dbname = db'
);
CREATE EXTENSION pglogical;
SELECT pglogical.create_node (
node_name: = 'subscriber1',
dsn: = 'host = pg13 port = 5432 dbname = db'
);

23. 23
Add tables
and
sequences
SELECT pglogical.replication_set_add_all_tables (
set_name := 'default',
schema_names := ARRAY ['public']
);
SELECT pglogical.replication_set_add_all_sequences
(
set_name : = 'default',
schema_names : = ARRAY ['public']
);

24. 24
Create
subscription
SELECT pglogical.create_subscription(
subscription_name := 'my_subscription',
provider_dsn := 'host = pg95
port = 5432
dbname = db',
);

25. 25
pglogical.create_subscription(
subscription_name name,
provider_dsn text,
replication_sets text[],
synchronize_structure boolean,
synchronize_data boolean,
forward_origins text[],
apply_delay interval
);
Create
subscription

26. 26
Check SELECT subscription_name, status
FROM pglogical.show_subscription_status();
subscription_name | status
------------------------+-------------
my_subscription | replicating

27. 27
Repeat c second_database
CREATE EXTENSION pglogical;
SELECT pglogical.create_node (...'provider'...);
SELECT pglogical.create_node (...'subscriber'...);
SELECT pglogical.replication_set_add_all_tables(...);
SELECT pglogical.replication_set_add_all_sequences(...);
SELECT pglogical.create_subscription(...);

28. 28
Testing and
application
testing

29. 29
Cutover/
Switch

30. 30
Post-switch

31. 31
Conclusions
• Pglogical is my preferred major upgrade method

32. 32
Conclusions
• Start simple and test everything
TEST! TEST! TEST!

33. 33
Conclusions
• Pglogical 3
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34. 34
Conclusions
• Kubernetes and Cloud Native friendly

35. Thank you!
Questions?
@irionr
florin-razvan-irion
www.enterprisedb.com/contact