This document summarizes a presentation about new features in PostgreSQL 9.4. It discusses enhancements for NoSQL support with JSON and GIN indexes, analytics with new aggregate functions and materialized views, increased flexibility with logical replication, easier administration using ALTER SYSTEM, and improved infrastructure for parallelization through dynamic background workers and shared memory. The presentation provides an overview of the status of 9.4 and highlights some of the major new categories of features.

1. PostgreSQL 9.4
JSON, Analytics, and More
Japan PostgreSQL Users Group
Satoshi Nagayasu
snaga@uptime.jp
@pgcon china 2014

2. Satoshi Nagayasu
• 2004
– NTT DATA
• 2005
– JPUG PR Director
• 2009
– Uptime Technologies
• 2010
– JPUG Chairperson
• 2013
– Minacare

3. Satoshi Nagayasu
• Database Engineer
• Data Center Engineer
• ITSM Specialist
• Data Steward
• System Architect
• Co-founder
• CTO

4. What I Did in PostgreSQL
• pgstatindex
• pageinspect
• xlogdump
– ... and lots of rejected patches! 
• Patch review
• PostgresForest, Postgres-XC
– at my prev jobs

5. Thanks to...
• Magnus Hagander
• Michael Paquier
• Toshi Harada
• Noriyoshi Shinoda
• ... and many pg guys!

6. Agenda
• 9.4 Overview
• NoSQL (JSON and GIN Index)
• Analytics (Aggregation & Mat.View)
• Replication and Beyond (Logical
Decoding)
• Administration (ALTER SYSTEM)
• Infrastructure (For Parallelization)

7. 9.4 Overview

8. 9.4 Overview - Status
• Current Status
– RC1 released on 20th November
• Officially announced 9.4 to be released
on 18th December (the next Thursday)

9. 9.4 Overview - Statistics
• As of beta2 (by Magnus Hagander)
– 2222 files changed
– 131,805 insertions (+)
– 59,333 deletions(-)
• As of RC1 (by Michael Paquier)
– 2183 files changed
– 374,421 insertions (+)
– 209,439 deletions (-)

10. 9.4 Overview - Changes

11. 9.4 Overview - Changes
Server
Indexes
General Performance
Monitoring
SSL
Server Settings
Replication and Recovery
Logical Decoding
Queries
Utility Commands
EXPLAIN
Views
Object Manipulation
Data Types
JSON
Functions
System Information Functions
Aggregates
Server‐Side Languages
PL/pgSQL Server‐Side Language
libpq
Client Applications
psql
Backslash Commands
pg_dump
pg_basebackup
Source Code
Additional Modules
pgbench
pg_stat_statements

12. Categories of
Enhancements
• NoSQL (JSON and GIN Index)
• Analytics (Aggregation & Mat.View)
• Replication+ (Logical Decoding)
• Administration (ALTER SYSTEM)
• Basic Infrastructure (Parallelization)

13. NoSQL
(JSON and GIN Index)

14. NoSQL - JSONB
• JSON vs. JSONB

15. NoSQL - JSONB
• “Binary JSON”
– Different from JSON, a text representation
– Faster for searching
• With JSONB...
– No duplicated keys allowed. Last wins.
– Key order not preserved.
– Can take advantages of GIN Index.

16. NoSQL - GIN Index
• JSON+btree vs. JSONB+GIN
– Btree indexes vs. GIN index
Table Index Size Comparison
http://www.slideshare.net/toshiharada/jpug-studyjsonbdatatype20141011-40103981

17. Analytics
(Aggregation & Materialized
View)

18. Analytics - Aggregation
• FILTER replaces CASE WHEN.

19. Analytics - Aggregation
• New Aggregate Functions
– percentile_cont()
– percentile_disc()
– mode()
– rank()
– dense_rank()
– percent_rank()
– cume_dist()

20. Analytics - Aggregation
• Ordered-set aggregates
– mode(), most common value in a subset

21. Analytics - Aggregation
• Ordered-set aggregates
– rank(), rank of a value in a subset

22. Analytics – Materialized
Views
• REFRESH MATERIALIZED VIEW
CONCURRENTLY myview
• Allows refreshing a MV concurrently
without taking exclusive lock.
• Refreshing a large MV can benefit from
CONCURRENTLY in terms of usability.

23. Replication and Beyond
(Logical Decoding)

24. Replication and Beyond –
Logical Decoding
• “Logical” representation from replication
stream
– INSERT/UPDATE/DELETE operations
– Can be replayed on different version/platform
• pg_recvlogical command
– It shows how it works
• Replication can be more flexible
– BDR (Bi-Directional Rep.), Slony, and more ...
– Continuous Backup as well

25. pg_recvlogical (contrib)

26. Administration
(ALTER SYSTEM)

27. Administration - ALTER
SYSTEM
• ALTER SYSTEM SET
– puts new value in postgresql.auto.conf
– pg_reload_conf() reloads them.
– postgresql.auto.conf takes priority over
postgresql.conf.
• ALTER SYSTEM RESET
– Remove values from postgresql.auto.conf.

28. Infrastructure
(For Parallelization)

29. Dynamic Background
Workers
• In 9.3, background workers must start at the
postmaster startup.
• After 9.4, they can be launched “on-demand”
basis.
• From parallelization point of view...
– It allows to launch multiple background
processes to execute child queries in
parallel.

30. Dynamic Shared Memory
• Shared memory can be allocated “on-demand”
basis
– Cf.) by background workers
• Main segment (ex. shared_buffers) still fixed
at startup
• Also supports lightweight message queue
• From parallelization point of view...
– It allows to share data and communicate with
several bgworker processes.

31. My Tiny Favorite
(pl/pgsql stacktrace)

32. pl/pgsql stacktrace
http://h50146.www5.hp.com/services/ci/opensource/pdfs/PostgreSQL_9_4%20_Ver_1_0.pdf

33. Many other enhancements,
so please try it asap.

34. Any Question?
有什么问题吗？

35. Thank you!
谢谢！