<s>
PostgreSQL	B-Application
(	O
,	O
)	O
,	O
also	O
known	O
as	O
Postgres	B-Application
,	O
is	O
a	O
free	B-License
and	I-License
open-source	I-License
relational	B-Application
database	I-Application
management	I-Application
system	I-Application
(	O
RDBMS	B-Application
)	O
emphasizing	O
extensibility	B-Architecture
and	O
SQL	B-Language
compliance	O
.	O
</s>
<s>
It	O
was	O
originally	O
named	O
POSTGRES	B-Application
,	O
referring	O
to	O
its	O
origins	O
as	O
a	O
successor	O
to	O
the	O
Ingres	B-Application
database	I-Application
developed	O
at	O
the	O
University	O
of	O
California	O
,	O
Berkeley	O
.	O
</s>
<s>
In	O
1996	O
,	O
the	O
project	O
was	O
renamed	O
to	O
PostgreSQL	B-Application
to	O
reflect	O
its	O
support	O
for	O
SQL	B-Language
.	O
</s>
<s>
After	O
a	O
review	O
in	O
2007	O
,	O
the	O
development	O
team	O
decided	O
to	O
keep	O
the	O
name	O
PostgreSQL	B-Application
and	O
the	O
alias	O
Postgres	B-Application
.	O
</s>
<s>
PostgreSQL	B-Application
features	O
transactions	B-General_Concept
with	O
Atomicity	B-Operating_System
,	I-Operating_System
Consistency	I-Operating_System
,	I-Operating_System
Isolation	I-Operating_System
,	I-Operating_System
Durability	I-Operating_System
(	O
ACID	B-Operating_System
)	O
properties	O
,	O
automatically	O
updatable	O
views	B-Language
,	O
materialized	B-Application
views	I-Application
,	O
triggers	B-Language
,	O
foreign	B-Application
keys	I-Application
,	O
and	O
stored	B-General_Concept
procedures	I-General_Concept
.	O
</s>
<s>
It	O
is	O
designed	O
to	O
handle	O
a	O
range	O
of	O
workloads	O
,	O
from	O
single	O
machines	O
to	O
data	O
warehouses	O
or	O
Web	O
services	O
with	O
many	O
concurrent	B-License
users	I-License
.	O
</s>
<s>
It	O
was	O
the	O
default	O
database	O
for	O
macOS	B-Operating_System
Server	I-Operating_System
and	O
is	O
also	O
available	O
for	O
Linux	B-Application
,	O
FreeBSD	B-Operating_System
,	O
OpenBSD	B-Operating_System
,	O
and	O
Windows	B-Application
.	O
</s>
<s>
PostgreSQL	B-Application
evolved	O
from	O
the	O
Ingres	B-Application
project	O
at	O
the	O
University	O
of	O
California	O
,	O
Berkeley	O
.	O
</s>
<s>
In	O
1982	O
,	O
the	O
leader	O
of	O
the	O
Ingres	B-Application
team	O
,	O
Michael	O
Stonebraker	O
,	O
left	O
Berkeley	O
to	O
make	O
a	O
proprietary	O
version	O
of	O
Ingres	B-Application
.	O
</s>
<s>
He	O
returned	O
to	O
Berkeley	O
in	O
1985	O
,	O
and	O
began	O
a	O
post-Ingres	O
project	O
to	O
address	O
the	O
problems	O
with	O
contemporary	O
database	O
systems	O
that	O
had	O
become	O
increasingly	O
clear	O
during	O
the	O
early	O
1980s	O
.	O
</s>
<s>
The	O
new	O
project	O
,	O
POSTGRES	B-Application
,	O
aimed	O
to	O
add	O
the	O
fewest	O
features	O
needed	O
to	O
completely	O
support	O
data	O
types	O
.	O
</s>
<s>
In	O
POSTGRES	B-Application
,	O
the	O
database	O
understood	O
relationships	O
,	O
and	O
could	O
retrieve	O
information	O
in	O
related	O
tables	O
in	O
a	O
natural	O
way	O
using	O
rules	O
.	O
</s>
<s>
POSTGRES	B-Application
used	O
many	O
of	O
the	O
ideas	O
of	O
Ingres	B-Application
,	O
but	O
not	O
its	O
code	O
.	O
</s>
<s>
Version	O
3	O
,	O
released	O
in	O
1991	O
,	O
again	O
re-wrote	O
the	O
rules	O
system	O
,	O
and	O
added	O
support	O
for	O
multiple	O
storage	O
managers	O
and	O
an	O
improved	O
query	B-Language
engine	O
.	O
</s>
<s>
Berkeley	O
released	O
POSTGRES	B-Application
under	O
an	O
MIT	B-License
License	I-License
variant	O
,	O
which	O
enabled	O
other	O
developers	O
to	O
use	O
the	O
code	O
for	O
any	O
use	O
.	O
</s>
<s>
At	O
the	O
time	O
,	O
POSTGRES	B-Application
used	O
an	O
Ingres-influenced	O
POSTQUEL	B-Language
query	I-Language
language	I-Language
interpreter	O
,	O
which	O
could	O
be	O
interactively	O
used	O
with	O
a	O
console	B-Device
application	I-Device
named	O
monitor	O
.	O
</s>
<s>
In	O
1994	O
,	O
Berkeley	O
graduate	O
students	O
Andrew	O
Yu	O
and	O
Jolly	O
Chen	O
replaced	O
the	O
POSTQUEL	B-Language
query	I-Language
language	I-Language
interpreter	O
with	O
one	O
for	O
the	O
SQL	B-Language
query	I-Language
language	O
,	O
creating	O
Postgres95	B-Application
.	O
</s>
<s>
Version	O
1.0	O
of	O
Postgres95	B-Application
was	O
announced	O
on	O
September	O
5	O
,	O
1995	O
,	O
with	O
a	O
more	O
liberal	O
license	O
that	O
enabled	O
the	O
software	O
to	O
be	O
freely	O
modifiable	O
.	O
</s>
<s>
In	O
1996	O
,	O
the	O
project	O
was	O
renamed	O
to	O
PostgreSQL	B-Application
to	O
reflect	O
its	O
support	O
for	O
SQL	B-Language
.	O
</s>
<s>
The	O
online	O
presence	O
at	O
the	O
website	O
PostgreSQL.org	O
began	O
on	O
October	O
22	O
,	O
1996	O
.	O
</s>
<s>
The	O
first	O
PostgreSQL	B-Application
release	O
formed	O
version	O
6.0	O
on	O
January	O
29	O
,	O
1997	O
.	O
</s>
<s>
Since	O
then	O
developers	O
and	O
volunteers	O
around	O
the	O
world	O
have	O
maintained	O
the	O
software	O
as	O
The	O
PostgreSQL	B-Application
Global	O
Development	O
Group	O
.	O
</s>
<s>
The	O
project	O
continues	O
to	O
make	O
releases	O
available	O
under	O
its	O
free	B-License
and	I-License
open-source	I-License
software	I-License
PostgreSQL	B-Application
License	O
.	O
</s>
<s>
PostgreSQL	B-Application
manages	O
concurrency	B-Operating_System
through	O
multiversion	B-Operating_System
concurrency	I-Operating_System
control	I-Operating_System
(	O
MVCC	B-Operating_System
)	O
,	O
which	O
gives	O
each	O
transaction	O
a	O
"	O
snapshot	O
"	O
of	O
the	O
database	O
,	O
allowing	O
changes	O
to	O
be	O
made	O
without	O
affecting	O
other	O
transactions	B-General_Concept
.	O
</s>
<s>
This	O
largely	O
eliminates	O
the	O
need	O
for	O
read	O
locks	O
,	O
and	O
ensures	O
the	O
database	O
maintains	O
ACID	B-Operating_System
principles	O
.	O
</s>
<s>
PostgreSQL	B-Application
offers	O
three	O
levels	O
of	O
transaction	B-General_Concept
isolation	I-General_Concept
:	O
Read	O
Committed	O
,	O
Repeatable	O
Read	O
and	O
Serializable	B-Operating_System
.	O
</s>
<s>
Because	O
PostgreSQL	B-Application
is	O
immune	O
to	O
dirty	O
reads	O
,	O
requesting	O
a	O
Read	O
Uncommitted	O
transaction	B-General_Concept
isolation	I-General_Concept
level	I-General_Concept
provides	O
read	O
committed	O
instead	O
.	O
</s>
<s>
PostgreSQL	B-Application
supports	O
full	O
serializability	B-Operating_System
via	O
the	O
serializable	B-Operating_System
snapshot	B-Operating_System
isolation	I-Operating_System
(	O
SSI	O
)	O
method	O
.	O
</s>
<s>
PostgreSQL	B-Application
includes	O
built-in	O
binary	O
replication	B-Architecture
based	O
on	O
shipping	O
the	O
changes	O
(	O
write-ahead	B-Algorithm
logs	I-Algorithm
(	O
WAL	O
)	O
)	O
to	O
replica	B-Architecture
nodes	O
asynchronously	O
,	O
with	O
the	O
ability	O
to	O
run	O
read-only	O
queries	B-Language
against	O
these	O
replicated	O
nodes	O
.	O
</s>
<s>
Earlier	O
replication	B-Architecture
software	O
that	O
allowed	O
similar	O
read	O
scaling	O
normally	O
relied	O
on	O
adding	O
replication	B-Architecture
triggers	B-Language
to	O
the	O
master	O
,	O
increasing	O
load	O
.	O
</s>
<s>
PostgreSQL	B-Application
includes	O
built-in	O
synchronous	O
replication	B-Architecture
that	O
ensures	O
that	O
,	O
for	O
each	O
write	O
transaction	O
,	O
the	O
master	O
waits	O
until	O
at	O
least	O
one	O
replica	B-Architecture
node	O
has	O
written	O
the	O
data	O
to	O
its	O
transaction	O
log	O
.	O
</s>
<s>
Synchronous	O
standby	O
servers	O
can	O
be	O
specified	O
in	O
the	O
configuration	O
which	O
determines	O
which	O
servers	O
are	O
candidates	O
for	O
synchronous	O
replication	B-Architecture
.	O
</s>
<s>
Synchronous	O
multi-master	B-Operating_System
replication	I-Operating_System
is	O
not	O
included	O
in	O
the	O
PostgreSQL	B-Application
core	O
.	O
</s>
<s>
Postgres-XC	O
which	O
is	O
based	O
on	O
PostgreSQL	B-Application
provides	O
scalable	O
synchronous	O
multi-master	B-Operating_System
replication	I-Operating_System
.	O
</s>
<s>
It	O
is	O
licensed	O
under	O
the	O
same	O
license	O
as	O
PostgreSQL	B-Application
.	O
</s>
<s>
A	O
related	O
project	O
is	O
called	O
Postgres-XL	B-Language
.	O
</s>
<s>
Postgres-R	O
is	O
yet	O
another	O
fork	B-Application
.	O
</s>
<s>
Bidirectional	O
replication	B-Architecture
(	O
BDR	O
)	O
is	O
an	O
asynchronous	O
multi-master	B-Operating_System
replication	I-Operating_System
system	O
for	O
PostgreSQL	B-Application
.	O
</s>
<s>
Tools	O
such	O
as	O
repmgr	O
make	O
managing	O
replication	B-Architecture
clusters	O
easier	O
.	O
</s>
<s>
Several	O
asynchronous	O
trigger-based	O
replication	B-Architecture
packages	O
are	O
available	O
.	O
</s>
<s>
These	O
remain	O
useful	O
even	O
after	O
introduction	O
of	O
the	O
expanded	O
core	O
abilities	O
,	O
for	O
situations	O
where	O
binary	O
replication	B-Architecture
of	O
a	O
full	O
database	O
cluster	O
is	O
inappropriate	O
:	O
</s>
<s>
PostgreSQL	B-Application
includes	O
built-in	O
support	O
for	O
regular	O
B-tree	B-Architecture
and	O
hash	B-Algorithm
table	I-Algorithm
indexes	O
,	O
and	O
four	O
index	O
access	O
methods	O
:	O
generalized	O
search	O
trees	O
(	O
GiST	B-Device
)	O
,	O
generalized	O
inverted	B-Algorithm
indexes	I-Algorithm
(	O
GIN	O
)	O
,	O
Space-Partitioned	O
GiST	B-Device
(	O
SP-GiST	O
)	O
and	O
Block	B-Language
Range	I-Language
Indexes	I-Language
(	O
BRIN	B-Language
)	O
.	O
</s>
<s>
In	O
addition	O
,	O
user-defined	O
index	O
methods	O
can	O
be	O
created	O
,	O
although	O
this	O
is	O
quite	O
an	O
involved	O
process	B-Operating_System
.	O
</s>
<s>
Indexes	O
in	O
PostgreSQL	B-Application
also	O
support	O
the	O
following	O
features	O
:	O
</s>
<s>
Expression	B-General_Concept
indexes	I-General_Concept
can	O
be	O
created	O
with	O
an	O
index	O
of	O
the	O
result	O
of	O
an	O
expression	O
or	O
function	O
,	O
instead	O
of	O
simply	O
the	O
value	O
of	O
a	O
column	O
.	O
</s>
<s>
Partial	B-Language
indexes	I-Language
,	O
which	O
only	O
index	O
part	O
of	O
a	O
table	O
,	O
can	O
be	O
created	O
by	O
adding	O
a	O
WHERE	O
clause	O
to	O
the	O
end	O
of	O
the	O
CREATE	O
INDEX	O
statement	O
.	O
</s>
<s>
The	O
planner	O
is	O
able	O
to	O
use	O
multiple	O
indexes	O
together	O
to	O
satisfy	O
complex	O
queries	B-Language
,	O
using	O
temporary	O
in-memory	O
bitmap	B-Data_Structure
index	I-Data_Structure
operations	O
(	O
useful	O
for	O
data	O
warehouse	O
applications	O
for	O
joining	O
a	O
large	O
fact	O
table	O
to	O
smaller	O
dimension	O
tables	O
such	O
as	O
those	O
arranged	O
in	O
a	O
star	B-Application
schema	I-Application
)	O
.	O
</s>
<s>
k-nearest	B-General_Concept
neighbors	I-General_Concept
(	O
k-NN	B-General_Concept
)	O
indexing	O
(	O
also	O
referred	O
to	O
KNN-GiST	O
)	O
provides	O
efficient	O
searching	O
of	O
"	O
closest	O
values	O
"	O
to	O
that	O
specified	O
,	O
useful	O
to	O
finding	O
similar	O
words	O
,	O
or	O
close	O
objects	O
or	O
locations	O
with	O
geospatial	B-General_Concept
data	I-General_Concept
.	O
</s>
<s>
Block	B-Language
Range	I-Language
Indexes	I-Language
(	O
BRIN	B-Language
)	O
.	O
</s>
<s>
In	O
PostgreSQL	B-Application
,	O
a	O
schema	B-Application
holds	O
all	O
objects	O
,	O
except	O
for	O
roles	O
and	O
tablespaces	B-General_Concept
.	O
</s>
<s>
Schemas	B-Application
effectively	O
act	O
like	O
namespaces	O
,	O
allowing	O
objects	O
of	O
the	O
same	O
name	O
to	O
co-exist	O
in	O
the	O
same	O
database	O
.	O
</s>
<s>
By	O
default	O
,	O
newly	O
created	O
databases	O
have	O
a	O
schema	B-Application
called	O
public	O
,	O
but	O
any	O
further	O
schemas	B-Application
can	O
be	O
added	O
,	O
and	O
the	O
public	O
schema	B-Application
is	O
n't	O
mandatory	O
.	O
</s>
<s>
A	O
setting	O
determines	O
the	O
order	O
in	O
which	O
PostgreSQL	B-Application
checks	O
schemas	B-Application
for	O
unqualified	O
objects	O
(	O
those	O
without	O
a	O
prefixed	O
schema	B-Application
)	O
.	O
</s>
<s>
This	O
default	O
can	O
be	O
set	O
on	O
a	O
database	O
or	O
role	B-General_Concept
level	O
,	O
but	O
as	O
it	O
is	O
a	O
session	O
parameter	O
,	O
it	O
can	O
be	O
freely	O
changed	O
(	O
even	O
multiple	O
times	O
)	O
during	O
a	O
client	O
session	O
,	O
affecting	O
that	O
session	O
only	O
.	O
</s>
<s>
Non-existent	O
schemas	B-Application
listed	O
in	O
search_path	O
are	O
silently	O
skipped	O
during	O
objects	O
lookup	O
.	O
</s>
<s>
New	O
objects	O
are	O
created	O
in	O
whichever	O
valid	O
schema	B-Application
(	O
one	O
that	O
presently	O
exists	O
)	O
appears	O
first	O
in	O
the	O
search_path	O
.	O
</s>
<s>
In	O
addition	O
,	O
users	O
can	O
create	O
their	O
own	O
data	O
types	O
which	O
can	O
usually	O
be	O
made	O
fully	O
indexable	O
via	O
PostgreSQL	B-Application
's	O
indexing	O
infrastructures	O
GiST	B-Device
,	O
GIN	O
,	O
SP-GiST	O
.	O
</s>
<s>
Examples	O
of	O
these	O
include	O
the	O
geographic	B-Application
information	I-Application
system	I-Application
(	O
GIS	B-Application
)	O
data	O
types	O
from	O
the	O
PostGIS	B-Application
project	O
for	O
PostgreSQL	B-Application
.	O
</s>
<s>
There	O
is	O
also	O
a	O
data	O
type	O
called	O
a	O
domain	O
,	O
which	O
is	O
the	O
same	O
as	O
any	O
other	O
data	O
type	O
but	O
with	O
optional	O
constraints	B-Application
defined	O
by	O
the	O
creator	O
of	O
that	O
domain	O
.	O
</s>
<s>
This	O
means	O
any	O
data	O
entered	O
into	O
a	O
column	O
using	O
the	O
domain	O
will	O
have	O
to	O
conform	O
to	O
whichever	O
constraints	B-Application
were	O
defined	O
as	O
part	O
of	O
the	O
domain	O
.	O
</s>
<s>
Inheritance	O
can	O
be	O
used	O
to	O
implement	O
table	O
partitioning	B-General_Concept
,	O
using	O
either	O
triggers	B-Language
or	O
rules	O
to	O
direct	O
inserts	B-Language
to	O
the	O
parent	O
table	O
into	O
the	O
proper	O
child	O
tables	O
.	O
</s>
<s>
In	O
particular	O
,	O
table	O
constraints	B-Application
are	O
not	O
currently	O
inheritable	O
.	O
</s>
<s>
All	O
check	O
constraints	B-Application
and	O
not-null	O
constraints	B-Application
on	O
a	O
parent	O
table	O
are	O
automatically	O
inherited	O
by	O
its	O
children	O
.	O
</s>
<s>
Other	O
types	O
of	O
constraints	B-Application
(	O
unique	O
,	O
primary	O
key	O
,	O
and	O
foreign	B-Application
key	I-Application
constraints	I-Application
)	O
are	O
not	O
inherited	O
.	O
</s>
<s>
Inheritance	O
provides	O
a	O
way	O
to	O
map	O
the	O
features	O
of	O
generalization	O
hierarchies	O
depicted	O
in	O
entity	B-Architecture
relationship	I-Architecture
diagrams	I-Architecture
(	O
ERDs	O
)	O
directly	O
into	O
the	O
PostgreSQL	B-Application
database	O
.	O
</s>
<s>
PostgreSQL	B-Application
can	O
link	O
to	O
other	O
systems	O
to	O
retrieve	O
data	O
via	O
foreign	O
data	O
wrappers	O
(	O
FDWs	O
)	O
.	O
</s>
<s>
These	O
can	O
take	O
the	O
form	O
of	O
any	O
data	O
source	O
,	O
such	O
as	O
a	O
file	O
system	O
,	O
another	O
relational	B-Application
database	I-Application
management	I-Application
system	I-Application
(	O
RDBMS	B-Application
)	O
,	O
or	O
a	O
web	O
service	O
.	O
</s>
<s>
This	O
means	O
that	O
regular	O
database	O
queries	B-Language
can	O
use	O
these	O
data	O
sources	O
like	O
regular	O
tables	O
,	O
and	O
even	O
join	O
multiple	O
data-sources	O
together	O
.	O
</s>
<s>
For	O
connecting	O
to	O
applications	O
,	O
PostgreSQL	B-Application
includes	O
the	O
built-in	O
interfaces	O
libpq	B-Application
(	O
the	O
official	O
C	B-Language
application	O
interface	O
)	O
and	O
ECPG	B-Language
(	O
an	O
embedded	O
C	B-Language
system	O
)	O
.	O
</s>
<s>
Third-party	O
libraries	O
for	O
connecting	O
to	O
PostgreSQL	B-Application
are	O
available	O
for	O
many	O
programming	O
languages	O
,	O
including	O
C++	B-Language
,	O
Java	B-Language
,	O
Julia	B-Application
,	O
Python	B-Language
,	O
Node.js	B-Language
,	O
Go	B-Application
,	O
and	O
Rust	B-Application
.	O
</s>
<s>
Procedural	O
languages	O
allow	O
developers	O
to	O
extend	O
the	O
database	O
with	O
custom	O
subroutines	O
(	O
functions	O
)	O
,	O
often	O
called	O
stored	B-General_Concept
procedures	I-General_Concept
.	O
</s>
<s>
These	O
functions	O
can	O
be	O
used	O
to	O
build	O
database	B-Language
triggers	I-Language
(	O
functions	O
invoked	O
on	O
modification	O
of	O
certain	O
data	O
)	O
and	O
custom	O
data	O
types	O
and	O
aggregate	O
functions	O
.	O
</s>
<s>
Procedural	O
languages	O
can	O
also	O
be	O
invoked	O
without	O
defining	O
a	O
function	O
,	O
using	O
a	O
DO	O
command	O
at	O
SQL	B-Language
level	O
.	O
</s>
<s>
Procedures	O
written	O
in	O
unsafe	O
languages	O
can	O
only	O
be	O
created	O
by	O
superusers	B-Application
,	O
because	O
they	O
allow	O
bypassing	O
a	O
database	O
's	O
security	O
restrictions	O
,	O
but	O
can	O
also	O
access	O
sources	O
external	O
to	O
the	O
database	O
.	O
</s>
<s>
Some	O
languages	O
like	O
Perl	B-Language
provide	O
both	O
safe	O
and	O
unsafe	O
versions	O
.	O
</s>
<s>
PostgreSQL	B-Application
has	O
built-in	O
support	O
for	O
three	O
procedural	O
languages	O
:	O
</s>
<s>
Plain	O
SQL	B-Language
(	O
safe	O
)	O
.	O
</s>
<s>
Simpler	O
SQL	B-Language
functions	I-Language
can	O
get	O
expanded	O
inline	O
into	O
the	O
calling	O
(	O
SQL	B-Language
)	O
query	B-Language
,	O
which	O
saves	O
function	O
call	O
overhead	O
and	O
allows	O
the	O
query	B-Language
optimizer	O
to	O
"	O
see	O
inside	O
"	O
the	O
function	O
.	O
</s>
<s>
Procedural	O
Language/PostgreSQL	O
(	O
PL/pgSQL	B-Language
)	O
(	O
safe	O
)	O
,	O
which	O
resembles	O
Oracle	O
's	O
Procedural	O
Language	O
for	O
SQL	B-Language
(	O
PL/SQL	B-Language
)	O
procedural	O
language	O
and	O
SQL/Persistent	O
Stored	O
Modules	O
(	O
SQL/PSM	B-Language
)	O
.	O
</s>
<s>
C	B-Language
(	O
unsafe	O
)	O
,	O
which	O
allows	O
loading	O
one	O
or	O
more	O
custom	O
shared	O
library	O
into	O
the	O
database	O
.	O
</s>
<s>
Functions	O
written	O
in	O
C	B-Language
offer	O
the	O
best	O
performance	O
,	O
but	O
bugs	O
in	O
code	O
can	O
crash	O
and	O
potentially	O
corrupt	O
the	O
database	O
.	O
</s>
<s>
Most	O
built-in	O
functions	O
are	O
written	O
in	O
C	B-Language
.	O
</s>
<s>
In	O
addition	O
,	O
PostgreSQL	B-Application
allows	O
procedural	O
languages	O
to	O
be	O
loaded	O
into	O
the	O
database	O
through	O
extensions	O
.	O
</s>
<s>
Three	O
language	O
extensions	O
are	O
included	O
with	O
PostgreSQL	B-Application
to	O
support	O
Perl	B-Language
,	O
Tcl	B-Operating_System
,	O
and	O
Python	B-Language
.	O
</s>
<s>
For	O
Python	B-Language
,	O
the	O
current	O
is	O
used	O
,	O
and	O
the	O
discontinued	O
is	O
no	O
longer	O
supported	O
as	O
of	O
PostgreSQL	B-Application
15	O
.	O
</s>
<s>
External	O
projects	O
provide	O
support	O
for	O
many	O
other	O
languages	O
,	O
including	O
PL/Java	O
,	O
JavaScript	B-Language
(	O
PL/V8	O
)	O
,	O
PL/Julia	O
,	O
PL/R	O
,	O
PL/Ruby	O
,	O
and	O
others	O
.	O
</s>
<s>
Triggers	B-Language
are	O
events	O
triggered	O
by	O
the	O
action	O
of	O
SQL	B-Language
data	B-Language
manipulation	I-Language
language	I-Language
(	O
DML	O
)	O
statements	O
.	O
</s>
<s>
For	O
example	O
,	O
an	O
INSERT	B-Language
statement	O
might	O
activate	O
a	O
trigger	O
that	O
checks	O
if	O
the	O
values	O
of	O
the	O
statement	O
are	O
valid	O
.	O
</s>
<s>
Most	O
triggers	B-Language
are	O
only	O
activated	O
by	O
either	O
INSERT	B-Language
or	O
UPDATE	B-Language
statements	O
.	O
</s>
<s>
Triggers	B-Language
are	O
fully	O
supported	O
and	O
can	O
be	O
attached	O
to	O
tables	O
.	O
</s>
<s>
Triggers	B-Language
can	O
be	O
per-column	O
and	O
conditional	O
,	O
in	O
that	O
UPDATE	B-Language
triggers	B-Language
can	O
target	O
specific	O
columns	O
of	O
a	O
table	O
,	O
and	O
triggers	B-Language
can	O
be	O
told	O
to	O
execute	O
under	O
a	O
set	O
of	O
conditions	O
as	O
specified	O
in	O
the	O
trigger	O
's	O
WHERE	O
clause	O
.	O
</s>
<s>
Triggers	B-Language
can	O
be	O
attached	O
to	O
views	B-Language
by	O
using	O
the	O
INSTEAD	O
OF	O
condition	O
.	O
</s>
<s>
Multiple	O
triggers	B-Language
are	O
fired	O
in	O
alphabetical	O
order	O
.	O
</s>
<s>
In	O
addition	O
to	O
calling	O
functions	O
written	O
in	O
the	O
native	O
PL/pgSQL	B-Language
,	O
triggers	B-Language
can	O
also	O
invoke	O
functions	O
written	O
in	O
other	O
languages	O
like	O
PL/Python	O
or	O
PL/Perl	O
.	O
</s>
<s>
PostgreSQL	B-Application
provides	O
an	O
asynchronous	O
messaging	O
system	O
that	O
is	O
accessed	O
through	O
the	O
NOTIFY	O
,	O
LISTEN	O
and	O
UNLISTEN	O
commands	O
.	O
</s>
<s>
Such	O
a	O
system	O
prevents	O
the	O
need	O
for	O
continuous	O
polling	B-General_Concept
by	O
applications	O
to	O
see	O
if	O
anything	O
has	O
yet	O
changed	O
,	O
and	O
reducing	O
unnecessary	O
overhead	O
.	O
</s>
<s>
Many	O
connectors	O
for	O
PostgreSQL	B-Application
provide	O
support	O
for	O
this	O
notification	O
system	O
(	O
including	O
libpq	B-Application
,	O
JDBC	O
,	O
Npgsql	O
,	O
psycopg	O
and	O
node.js	B-Language
)	O
so	O
it	O
can	O
be	O
used	O
by	O
external	O
applications	O
.	O
</s>
<s>
PostgreSQL	B-Application
can	O
act	O
as	O
an	O
effective	O
,	O
persistent	O
"	B-Operating_System
pub/sub	I-Operating_System
"	I-Operating_System
server	I-Operating_System
or	O
job	O
server	O
by	O
combining	O
LISTEN	O
with	O
FOR	O
UPDATE	B-Language
SKIP	O
LOCKED	O
.	O
</s>
<s>
Rules	O
allow	O
the	O
"	O
query	B-Language
tree	O
"	O
of	O
an	O
incoming	O
query	B-Language
to	O
be	O
rewritten	O
.	O
</s>
<s>
"	O
Query	B-Language
Re-Write	O
Rules	O
"	O
are	O
attached	O
to	O
a	O
table/class	O
and	O
"	O
Re-Write	O
"	O
the	O
incoming	O
DML	O
(	O
select	O
,	O
insert	B-Language
,	O
update	B-Language
,	O
and/or	O
delete	O
)	O
into	O
one	O
or	O
more	O
queries	B-Language
that	O
either	O
replace	O
the	O
original	O
DML	O
statement	O
or	O
execute	O
in	O
addition	O
to	O
it	O
.	O
</s>
<s>
Query	B-Language
Re-Write	O
occurs	O
after	O
DML	O
statement	O
parsing	O
,	O
but	O
before	O
query	B-Language
planning	O
.	O
</s>
<s>
The	O
Oversized-Attribute	O
Storage	O
Technique	O
(	O
TOAST	O
)	O
is	O
used	O
to	O
transparently	O
store	O
large	O
table	O
attributes	O
(	O
such	O
as	O
big	O
MIME	O
attachments	O
or	O
XML	B-Protocol
messages	O
)	O
in	O
a	O
separate	O
area	O
,	O
with	O
automatic	O
compression	O
.	O
</s>
<s>
Embedded	B-Language
SQL	I-Language
is	O
implemented	O
using	O
preprocessor	O
.	O
</s>
<s>
SQL	B-Language
code	O
is	O
first	O
written	O
embedded	O
into	O
C	B-Language
code	O
.	O
</s>
<s>
Then	O
code	O
is	O
run	O
through	O
ECPG	B-Language
preprocessor	O
,	O
which	O
replaces	O
SQL	B-Language
with	O
calls	O
to	O
code	O
library	O
.	O
</s>
<s>
Then	O
code	O
can	O
be	O
compiled	O
using	O
a	O
C	B-Language
compiler	O
.	O
</s>
<s>
Embedding	O
works	O
also	O
with	O
C++	B-Language
but	O
it	O
does	O
not	O
recognize	O
all	O
C++	B-Language
constructs	O
.	O
</s>
<s>
PostgreSQL	B-Application
server	O
is	O
process-based	O
(	O
not	O
threaded	O
)	O
,	O
and	O
uses	O
one	O
operating	O
system	B-Operating_System
process	I-Operating_System
per	O
database	O
session	O
.	O
</s>
<s>
Many	O
types	O
of	O
queries	B-Language
can	O
also	O
be	O
parallelized	O
across	O
multiple	O
background	O
worker	O
processes	O
,	O
taking	O
advantage	O
of	O
multiple	O
CPUs	O
or	O
cores	O
.	O
</s>
<s>
Client	O
applications	O
can	O
use	O
threads	O
and	O
create	O
multiple	O
database	B-General_Concept
connections	I-General_Concept
from	O
each	O
thread	O
.	O
</s>
<s>
PostgreSQL	B-Application
manages	O
its	O
internal	O
security	O
on	O
a	O
per-role	O
basis	O
.	O
</s>
<s>
A	O
role	B-General_Concept
is	O
generally	O
regarded	O
to	O
be	O
a	O
user	O
(	O
a	O
role	B-General_Concept
that	O
can	O
log	O
in	O
)	O
,	O
or	O
a	O
group	O
(	O
a	O
role	B-General_Concept
of	O
which	O
other	O
roles	O
are	O
members	O
)	O
.	O
</s>
<s>
Permissions	O
can	O
be	O
granted	O
or	O
revoked	O
on	O
any	O
object	O
down	O
to	O
the	O
column	O
level	O
,	O
and	O
can	O
also	O
allow/prevent	O
the	O
creation	O
of	O
new	O
objects	O
at	O
the	O
database	O
,	O
schema	B-Application
or	O
table	O
levels	O
.	O
</s>
<s>
PostgreSQL	B-Application
's	O
SECURITY	O
LABEL	O
feature	O
(	O
extension	O
to	O
SQL	B-Language
standards	O
)	O
,	O
allows	O
for	O
additional	O
security	O
;	O
with	O
a	O
bundled	O
loadable	O
module	O
that	O
supports	O
label-based	O
mandatory	O
access	O
control	O
(	O
MAC	O
)	O
based	O
on	O
Security-Enhanced	B-Application
Linux	I-Application
(	O
SELinux	B-Application
)	O
security	O
policy	O
.	O
</s>
<s>
PostgreSQL	B-Application
natively	O
supports	O
a	O
broad	O
number	O
of	O
external	O
authentication	O
mechanisms	O
,	O
including	O
:	O
</s>
<s>
The	O
GSSAPI	O
,	O
SSPI	B-Protocol
,	O
Kerberos	B-Protocol
,	O
peer	O
,	O
ident	O
and	O
certificate	O
methods	O
can	O
also	O
use	O
a	O
specified	O
"	O
map	O
"	O
file	O
that	O
lists	O
which	O
users	O
matched	O
by	O
that	O
authentication	O
system	O
are	O
allowed	O
to	O
connect	O
as	O
a	O
specific	O
database	O
user	O
.	O
</s>
<s>
This	O
allows	O
control	O
over	O
which	O
user	O
can	O
connect	O
to	O
which	O
database	O
,	O
where	O
they	O
can	O
connect	O
from	O
(	O
IP	O
address	O
,	O
IP	O
address	O
range	O
,	O
domain	O
socket	O
)	O
,	O
which	O
authentication	O
system	O
will	O
be	O
enforced	O
,	O
and	O
whether	O
the	O
connection	O
must	O
use	O
Transport	B-Protocol
Layer	I-Protocol
Security	I-Protocol
(	O
TLS	O
)	O
.	O
</s>
<s>
PostgreSQL	B-Application
claims	O
high	O
,	O
but	O
not	O
complete	O
,	O
conformance	O
with	O
the	O
latest	O
SQL	B-Language
standard	I-Language
(	O
for	O
version	O
13	O
"	O
in	O
September	O
2020	O
,	O
PostgreSQL	B-Application
conforms	O
to	O
at	O
least	O
170	O
of	O
the	O
179	O
mandatory	O
features	O
for	O
SQL:2016	B-Language
Core	O
conformance	O
"	O
,	O
and	O
no	O
other	O
databases	O
fully	O
conformed	O
to	O
it	O
)	O
.	O
</s>
<s>
In	O
PostgreSQL	B-Application
they	O
are	O
folded	O
,	O
internally	O
,	O
to	O
lower	O
case	O
characters	O
whereas	O
the	O
standard	O
says	O
that	O
unquoted	O
identifiers	O
should	O
be	O
folded	O
to	O
upper	O
case	O
.	O
</s>
<s>
Other	O
shortcomings	O
concern	O
the	O
absence	O
of	O
temporal	O
tables	O
allowing	O
automatic	O
logging	O
of	O
row	O
versions	O
during	O
transactions	B-General_Concept
with	O
the	O
possibility	O
of	O
browsing	O
in	O
time	O
(	O
FOR	O
SYSTEM	O
TIME	O
predicate	O
)	O
.	O
</s>
<s>
Many	O
informal	O
performance	O
studies	O
of	O
PostgreSQL	B-Application
have	O
been	O
done	O
.	O
</s>
<s>
The	O
first	O
industry-standard	O
and	O
peer-validated	O
benchmark	O
was	O
completed	O
in	O
June	O
2007	O
,	O
using	O
the	O
Sun	B-Language
Java	I-Language
System	I-Language
Application	I-Language
Server	I-Language
(	O
proprietary	O
version	O
of	O
GlassFish	B-Language
)	O
9.0	O
Platform	O
Edition	O
,	O
UltraSPARC	O
T1-based	O
Sun	B-Architecture
Fire	I-Architecture
server	O
and	O
PostgreSQL	B-Application
8.2	O
.	O
</s>
<s>
This	O
result	O
of	O
778.14	O
SPECjAppServer2004	O
JOPS	O
@Standard	O
compares	O
favourably	O
with	O
the	O
874	O
JOPS	O
@Standard	O
with	O
Oracle	O
10	O
on	O
an	O
Itanium-based	O
HP-UX	B-Application
system	O
.	O
</s>
<s>
The	O
default	O
configuration	O
of	O
PostgreSQL	B-Application
uses	O
only	O
a	O
small	O
amount	O
of	O
dedicated	O
memory	O
for	O
performance-critical	O
purposes	O
such	O
as	O
caching	O
database	O
blocks	O
and	O
sorting	O
.	O
</s>
<s>
This	O
limitation	O
is	O
primarily	O
because	O
older	O
operating	O
systems	O
required	O
kernel	O
changes	O
to	O
allow	O
allocating	O
large	O
blocks	O
of	O
shared	B-Operating_System
memory	I-Operating_System
.	O
</s>
<s>
PostgreSQL.org	O
provides	O
advice	O
on	O
basic	O
recommended	O
performance	O
practice	O
in	O
a	O
wiki	B-Protocol
.	O
</s>
<s>
In	O
April	O
2012	O
,	O
Robert	O
Haas	O
of	O
EnterpriseDB	B-Language
demonstrated	O
PostgreSQL	B-Application
9.2	O
'	O
s	O
linear	O
CPU	O
scalability	O
using	O
a	O
server	O
with	O
64	O
cores	O
.	O
</s>
<s>
Matloob	O
Khushi	O
performed	O
benchmarking	O
between	O
PostgreSQL	B-Application
9.0	O
and	O
MySQL	O
5.6.15	O
for	O
their	O
ability	O
to	O
process	B-Operating_System
genomic	O
data	O
.	O
</s>
<s>
In	O
his	O
performance	O
analysis	O
he	O
found	O
that	O
PostgreSQL	B-Application
extracts	O
overlapping	O
genomic	O
regions	O
eight	O
times	O
faster	O
than	O
MySQL	B-Application
using	O
two	O
datasets	O
of	O
80,000	O
each	O
forming	O
random	O
human	O
DNA	O
regions	O
.	O
</s>
<s>
Insertion	O
and	O
data	O
uploads	O
in	O
PostgreSQL	B-Application
were	O
also	O
better	O
,	O
although	O
general	O
searching	O
ability	O
of	O
both	O
databases	O
was	O
almost	O
equivalent	O
.	O
</s>
<s>
PostgreSQL	B-Application
is	O
available	O
for	O
the	O
following	O
operating	O
systems	O
:	O
Linux	B-Application
(	O
all	O
recent	O
distributions	O
)	O
,	O
64-bit	B-Device
ARM	B-Architecture
and	O
x86-64	B-Device
installers	O
available	O
and	O
tested	O
for	O
macOS	B-Application
(	O
OS	O
X	O
)	O
version	O
10.12	O
and	O
newer	O
,	O
Windows	B-Application
(	O
with	O
installers	O
available	O
and	O
tested	O
for	O
64-bit	B-Device
Windows	B-Device
Server	I-Device
2019	I-Device
and	O
2016	O
;	O
some	O
older	O
PostgreSQL	B-Application
versions	O
were	O
tested	O
back	O
to	O
Windows	B-Application
2012	O
R2	O
)	O
,	O
FreeBSD	B-Operating_System
,	O
OpenBSD	B-Operating_System
,	O
NetBSD	B-Device
,	O
and	O
these	O
without	O
official	O
(	O
though	O
unofficial	O
likely	O
available	O
)	O
binary	O
executables	O
,	O
Solaris	B-Application
,	O
AIX	B-Application
,	O
and	O
HP-UX	B-Application
.	O
</s>
<s>
PostgreSQL	B-Application
can	O
be	O
expected	O
to	O
work	O
on	O
any	O
of	O
the	O
following	O
instruction	B-General_Concept
set	I-General_Concept
architectures	I-General_Concept
(	O
and	O
operating	O
systems	O
)	O
:	O
64-bit	B-Device
x86-64	O
and	O
32-bit	O
x86	B-Operating_System
on	O
Windows	B-Application
XP	I-Application
(	O
or	O
later	O
)	O
and	O
other	O
operating	O
systems	O
;	O
these	O
are	O
supported	O
on	O
other	O
than	O
Windows	B-Application
:	O
64-bit	B-Device
ARM	B-Architecture
and	O
the	O
older	O
32-bit	O
ARM	B-Architecture
,	O
including	O
older	O
such	O
as	O
ARMv6	O
in	O
Raspberry	B-Operating_System
Pi	I-Operating_System
)	O
,	O
z/Architecture	B-Device
,	O
S/390	B-Device
,	O
PowerPC	B-Architecture
(	O
incl	O
.	O
</s>
<s>
64-bit	B-Device
Power	B-Architecture
ISA	I-Architecture
)	O
,	O
SPARC	B-Architecture
(	O
also	O
64-bit	B-Device
)	O
,	O
IA-64	O
Itanium	B-General_Concept
(	O
HP-UX	B-Application
)	O
,	O
MIPS	B-Device
and	O
PA-RISC	B-Device
.	O
</s>
<s>
Open	O
source	O
front-ends	B-Architecture
and	O
tools	O
for	O
administering	O
PostgreSQL	B-Application
include	O
:	O
</s>
<s>
psql	O
The	O
primary	O
front-end	B-Architecture
for	O
PostgreSQL	B-Application
is	O
the	O
command-line	B-Application
program	I-Application
,	O
which	O
can	O
be	O
used	O
to	O
enter	O
SQL	B-Language
queries	I-Language
directly	O
,	O
or	O
execute	O
them	O
from	O
a	O
file	O
.	O
</s>
<s>
In	O
addition	O
,	O
psql	O
provides	O
a	O
number	O
of	O
meta-commands	O
and	O
various	O
shell-like	O
features	O
to	O
facilitate	O
writing	O
scripts	O
and	O
automating	O
a	O
wide	O
variety	O
of	O
tasks	O
;	O
for	O
example	O
tab	O
completion	O
of	O
object	O
names	O
and	O
SQL	B-Language
syntax	O
.	O
</s>
<s>
pgAdmin	O
The	O
pgAdmin	O
package	O
is	O
a	O
free	B-License
and	I-License
open-source	I-License
graphical	B-Application
user	I-Application
interface	I-Application
(	O
GUI	B-Application
)	O
administration	O
tool	O
for	O
PostgreSQL	B-Application
,	O
which	O
is	O
supported	O
on	O
many	O
computer	O
platforms	O
.	O
</s>
<s>
The	O
first	O
prototype	O
,	O
named	O
pgManager	B-Application
,	O
was	O
written	O
for	O
PostgreSQL	B-Application
6.3.2	O
from	O
1998	O
,	O
and	O
rewritten	O
and	O
released	O
as	O
pgAdmin	O
under	O
the	O
GNU	O
General	O
Public	O
License	O
(	O
GPL	O
)	O
in	O
later	O
months	O
.	O
</s>
<s>
The	O
third	O
version	O
,	O
pgAdmin	O
III	O
,	O
was	O
originally	O
released	O
under	O
the	O
Artistic	B-License
License	I-License
and	O
then	O
released	O
under	O
the	O
same	O
license	O
as	O
PostgreSQL	B-Application
.	O
</s>
<s>
Unlike	O
prior	O
versions	O
that	O
were	O
written	O
in	O
Visual	B-Language
Basic	I-Language
,	O
pgAdmin	O
III	O
is	O
written	O
in	O
C++	B-Language
,	O
using	O
the	O
wxWidgets	B-Language
framework	O
allowing	O
it	O
to	O
run	O
on	O
most	O
common	O
operating	O
systems	O
.	O
</s>
<s>
The	O
query	B-Language
tool	O
includes	O
a	O
scripting	O
language	O
called	O
pgScript	O
for	O
supporting	O
admin	O
and	O
development	O
tasks	O
.	O
</s>
<s>
pgAdmin	O
4	O
backend	B-Architecture
was	O
written	O
in	O
Python	B-Language
,	O
using	O
Flask	O
and	O
Qt	B-Language
framework	I-Language
.	O
</s>
<s>
phpPgAdmin	O
phpPgAdmin	O
is	O
a	O
web-based	O
administration	O
tool	O
for	O
PostgreSQL	B-Application
written	O
in	O
PHP	O
and	O
based	O
on	O
the	O
popular	O
phpMyAdmin	B-Application
interface	O
originally	O
written	O
for	O
MySQL	B-Application
administration	O
.	O
</s>
<s>
PostgreSQL	B-Application
Studio	O
PostgreSQL	B-Application
Studio	O
allows	O
users	O
to	O
perform	O
essential	O
PostgreSQL	B-Application
database	O
development	O
tasks	O
from	O
a	O
web-based	O
console	O
.	O
</s>
<s>
PostgreSQL	B-Application
Studio	O
allows	O
users	O
to	O
work	O
with	O
cloud	O
databases	O
without	O
the	O
need	O
to	O
open	O
firewalls	O
.	O
</s>
<s>
TeamPostgreSQL	O
AJAX/JavaScript	O
-driven	O
web	O
interface	O
for	O
PostgreSQL	B-Application
.	O
</s>
<s>
The	O
interface	O
offers	O
tabbed	O
SQL	B-Language
editor	O
with	O
autocompletion	O
,	O
row	O
editing	O
widgets	O
,	O
click-through	O
foreign	B-Application
key	I-Application
navigation	O
between	O
rows	O
and	O
tables	O
,	O
favorites	O
management	O
for	O
commonly	O
used	O
scripts	O
,	O
among	O
other	O
features	O
.	O
</s>
<s>
Supports	O
SSH	O
for	O
both	O
the	O
web	O
interface	O
and	O
the	O
database	B-General_Concept
connections	I-General_Concept
.	O
</s>
<s>
Installers	O
are	O
available	O
for	O
Windows	B-Application
,	O
Macintosh	O
,	O
and	O
Linux	B-Application
,	O
and	O
a	O
simple	O
cross-platform	O
archive	O
that	O
runs	O
from	O
a	O
script	O
.	O
</s>
<s>
LibreOffice	B-Application
,	O
OpenOffice.org	B-Application
LibreOffice	B-Application
and	O
OpenOffice.org	B-Application
Base	I-Application
can	O
be	O
used	O
as	O
a	O
front-end	B-Architecture
for	O
PostgreSQL	B-Application
.	O
</s>
<s>
pgBadger	O
The	O
pgBadger	O
PostgreSQL	B-Application
log	O
analyzer	O
generates	O
detailed	O
reports	O
from	O
a	O
PostgreSQL	B-Application
log	O
file	O
.	O
</s>
<s>
pgDevOps	O
pgDevOps	O
is	O
a	O
suite	O
of	O
web	O
tools	O
to	O
install	O
&	O
manage	O
multiple	O
PostgreSQL	B-Application
versions	O
,	O
extensions	O
,	O
and	O
community	O
components	O
,	O
develop	O
SQL	B-Language
queries	I-Language
,	O
monitor	O
running	O
databases	O
and	O
find	O
performance	O
problems	O
.	O
</s>
<s>
Adminer	B-Language
Adminer	B-Language
is	O
a	O
simple	O
web-based	O
administration	O
tool	O
for	O
PostgreSQL	B-Application
and	O
others	O
,	O
written	O
in	O
PHP	O
.	O
</s>
<s>
pgBackRest	O
pgBackRest	O
is	O
a	O
backup	O
and	O
restore	O
tool	O
for	O
PostgreSQL	B-Application
that	O
provides	O
support	O
for	O
full	O
,	O
differential	O
,	O
and	O
incremental	O
backups	O
.	O
</s>
<s>
pgaudit	O
pgaudit	O
is	O
a	O
PostgreSQL	B-Application
extension	O
that	O
provides	O
detailed	O
session	O
and/or	O
object	O
audit	O
logging	O
via	O
the	O
standard	O
logging	O
facility	O
provided	O
by	O
PostgreSQL	B-Application
.	O
</s>
<s>
A	O
number	O
of	O
companies	O
offer	O
proprietary	O
tools	O
for	O
PostgreSQL	B-Application
.	O
</s>
<s>
These	O
tools	O
mostly	O
share	O
the	O
administration	O
features	O
with	O
the	O
open	O
source	O
tools	O
but	O
offer	O
improvements	O
in	O
data	B-Application
modeling	I-Application
,	O
importing	O
,	O
exporting	O
or	O
reporting	O
.	O
</s>
<s>
Notable	O
organizations	O
and	O
products	O
that	O
use	O
PostgreSQL	B-Application
as	O
the	O
primary	O
database	O
include	O
:	O
</s>
<s>
Microsoft	O
,	O
used	O
for	O
a	O
petabyte-scale	O
“	O
Release	O
Quality	O
View	B-Language
”	O
(	O
RQV	O
)	O
analytics	O
dashboard	O
,	O
which	O
tracks	O
quality	O
of	O
Windows	B-Application
updates	O
analyzing	O
20K	O
types	O
of	O
metrics	O
from	O
over	O
800M	O
Windows	B-Application
devices	O
.	O
</s>
<s>
In	O
2009	O
,	O
the	O
social-networking	O
website	O
Myspace	B-Application
used	O
Aster	O
Data	O
Systems	O
's	O
nCluster	O
database	O
for	O
data	O
warehousing	O
,	O
which	O
was	O
built	O
on	O
unmodified	O
PostgreSQL	B-Application
.	O
</s>
<s>
Geni.com	O
uses	O
PostgreSQL	B-Application
for	O
their	O
main	O
genealogy	O
database	O
.	O
</s>
<s>
Reddit	B-Application
social	O
news	O
website	O
.	O
</s>
<s>
Skype	B-Application
VoIP	O
application	O
,	O
central	O
business	O
databases	O
.	O
</s>
<s>
MusicBrainz	B-Application
,	O
open	O
online	O
music	O
encyclopedia	O
.	O
</s>
<s>
Instagram	B-Application
,	O
a	O
mobile	O
photo-sharing	O
service	O
.	O
</s>
<s>
Yandex	O
,	O
a	O
Russian	O
internet	O
company	O
switched	O
its	O
Yandex.Mail	O
service	O
from	O
Oracle	O
to	O
Postgres	B-Application
.	O
</s>
<s>
Amazon	O
Redshift	O
,	O
part	O
of	O
AWS	B-Application
,	O
a	O
columnar	O
online	B-Application
analytical	I-Application
processing	I-Application
(	O
OLAP	B-Application
)	O
system	O
based	O
on	O
ParAccel	O
's	O
Postgres	B-Application
modifications	O
.	O
</s>
<s>
National	O
Oceanic	O
and	O
Atmospheric	O
Administration	O
's	O
(	O
NOAA	O
)	O
National	O
Weather	O
Service	O
(	O
NWS	O
)	O
,	O
Interactive	O
Forecast	O
Preparation	O
System	O
(	O
IFPS	O
)	O
,	O
a	O
system	O
that	O
integrates	O
data	O
from	O
the	O
NEXRAD	B-Algorithm
weather	B-Application
radars	I-Application
,	O
surface	O
,	O
and	O
hydrology	O
systems	O
to	O
build	O
detailed	O
localized	O
forecast	O
models	O
.	O
</s>
<s>
United	O
Kingdom	O
's	O
national	O
weather	O
service	O
,	O
Met	O
Office	O
,	O
has	O
begun	O
swapping	O
Oracle	O
for	O
PostgreSQL	B-Application
in	O
a	O
strategy	O
to	O
deploy	O
more	O
open	O
source	O
technology	O
.	O
</s>
<s>
WhitePages.com	O
had	O
been	O
using	O
Oracle	O
and	O
MySQL	B-Application
,	O
but	O
when	O
it	O
came	O
to	O
moving	O
its	O
core	O
directories	O
in-house	O
,	O
it	O
turned	O
to	O
PostgreSQL	B-Application
.	O
</s>
<s>
Because	O
WhitePages.com	O
needs	O
to	O
combine	O
large	O
sets	O
of	O
data	O
from	O
multiple	O
sources	O
,	O
PostgreSQL	B-Application
's	O
ability	O
to	O
load	O
and	O
index	O
data	O
at	O
high	O
rates	O
was	O
a	O
key	O
to	O
its	O
decision	O
to	O
use	O
PostgreSQL	B-Application
.	O
</s>
<s>
FlightAware	B-Application
,	O
a	O
flight	O
tracking	O
website	O
.	O
</s>
<s>
The	O
Guardian	O
migrated	O
from	O
MongoDB	B-Application
to	O
PostgreSQL	B-Application
in	O
2018	O
.	O
</s>
<s>
Some	O
notable	O
vendors	O
offer	O
PostgreSQL	B-Application
as	O
software	B-Architecture
as	I-Architecture
a	I-Architecture
service	I-Architecture
:	O
</s>
<s>
Heroku	B-General_Concept
,	O
a	O
platform	B-Application
as	I-Application
a	I-Application
service	I-Application
provider	O
,	O
has	O
supported	O
PostgreSQL	B-Application
since	O
the	O
start	O
in	O
2007	O
.	O
</s>
<s>
They	O
offer	O
value-add	O
features	O
like	O
full	O
database	O
roll-back	O
(	O
ability	O
to	O
restore	O
a	O
database	O
from	O
any	O
specified	O
time	O
)	O
,	O
which	O
is	O
based	O
on	O
WAL-E	O
,	O
open-source	O
software	O
developed	O
by	O
Heroku	B-General_Concept
.	O
</s>
<s>
In	O
January	O
2012	O
,	O
EnterpriseDB	B-Language
released	O
a	O
cloud	O
version	O
of	O
both	O
PostgreSQL	B-Application
and	O
their	O
own	O
proprietary	O
Postgres	B-Language
Plus	I-Language
Advanced	I-Language
Server	I-Language
with	O
automated	O
provisioning	O
for	O
failover	O
,	O
replication	B-Architecture
,	O
load-balancing	O
,	O
and	O
scaling	O
.	O
</s>
<s>
It	O
runs	O
on	O
Amazon	B-Application
Web	I-Application
Services	I-Application
.	O
</s>
<s>
Since	O
2015	O
,	O
Postgres	B-Application
Advanced	O
Server	O
has	O
been	O
offered	O
as	O
ApsaraDB	O
for	O
PPAS	O
,	O
a	O
relational	B-Application
database	I-Application
as	O
a	O
service	O
on	O
Alibaba	B-General_Concept
Cloud	I-General_Concept
.	O
</s>
<s>
VMware	O
has	O
offered	O
vFabric	O
Postgres	B-Application
(	O
also	O
termed	O
vPostgres	O
)	O
for	O
private	O
clouds	O
on	O
VMware	B-Application
vSphere	I-Application
since	O
May	O
2012	O
.	O
</s>
<s>
In	O
November	O
2013	O
,	O
Amazon	B-Application
Web	I-Application
Services	I-Application
announced	O
the	O
addition	O
of	O
PostgreSQL	B-Application
to	O
their	O
Relational	B-Application
Database	I-Application
Service	O
offering	O
.	O
</s>
<s>
In	O
November	O
2016	O
,	O
Amazon	B-Application
Web	I-Application
Services	I-Application
announced	O
the	O
addition	O
of	O
PostgreSQL	B-Application
compatibility	O
to	O
their	O
cloud-native	O
Amazon	O
Aurora	O
managed	O
database	O
offering	O
.	O
</s>
<s>
In	O
May	O
2019	O
,	O
Alibaba	B-General_Concept
Cloud	I-General_Concept
announced	O
PolarDB	O
for	O
PostgreSQL	B-Application
.	O
</s>
<s>
Jelastic	B-General_Concept
Multicloud	B-General_Concept
Platform	B-Application
as	I-Application
a	I-Application
Service	I-Application
provides	O
container-based	O
PostgreSQL	B-Application
support	O
since	O
2011	O
.	O
</s>
<s>
They	O
offer	O
automated	O
asynchronous	O
master-slave	B-Architecture
replication	I-Architecture
of	O
PostgreSQL	B-Application
available	O
from	O
marketplace	O
.	O
</s>
<s>
In	O
June	O
2019	O
,	O
IBM	B-General_Concept
Cloud	I-General_Concept
announced	O
.	O
</s>
<s>
+	O
Release	O
history	O
Release	O
First	O
release	O
Latest	O
minor	O
version	O
Latest	O
release	O
End	O
oflife	O
Milestones	O
6.0	O
1997-01-29	O
First	O
formal	O
release	O
of	O
PostgreSQL	B-Application
,	O
unique	O
indexes	O
,	O
pg_dumpall	O
utility	O
,	O
ident	O
authentication	O
6.1	O
1997-06-08	O
1997-07-22	O
Multicolumn	O
indexes	O
,	O
sequences	O
,	O
money	O
data	O
type	O
,	O
GEQO	O
(	O
GEnetic	O
Query	B-Language
Optimizer	O
)	O
6.2	O
1997-10-02	O
1997-10-17	O
JDBC	O
interface	O
,	O
triggers	B-Language
,	O
server	O
programming	O
interface	O
,	O
constraints	B-Application
6.3	O
1998-03-01	O
1998-04-07	O
2003-03-01	O
SQL-92	O
subselect	O
ability	O
,	O
PL/pgTCL	O
6.4	O
1998-10-30	O
1998-12-20	O
2003-10-30	O
VIEWs	B-Language
(	O
then	O
only	O
read-only	O
)	O
and	O
RULEs	O
,	O
PL/pgSQL	B-Language
6.5	O
1999-06-09	O
1999-10-13	O
2004-06-09	O
MVCC	B-Operating_System
,	O
temporary	O
tables	O
,	O
more	O
SQL	B-Language
statement	O
support	O
(	O
CASE	O
,	O
INTERSECT	O
,	O
and	O
EXCEPT	O
)	O
7.0	O
2000-05-08	O
2000-11-11	O
2004-05-08	O
Foreign	B-Application
keys	I-Application
,	O
SQL-92	O
syntax	O
for	O
joins	B-Language
7.1	O
2001-04-13	O
2001-08-15	O
2006-04-13	O
Write-ahead	B-Algorithm
log	I-Algorithm
,	O
outer	O
joins	B-Language
7.2	O
2002-02-04	O
2005-05-09	O
2007-02-04	O
PL/Python	O
,	O
OIDs	O
no	O
longer	O
required	O
,	O
internationalization	B-General_Concept
of	O
messages	O
7.3	O
2002-11-27	O
2008-01-07	O
2007-11-27	O
Schema	B-Application
,	O
table	O
function	O
,	O
prepared	B-Language
query	I-Language
7.4	O
2003-11-17	O
2010-10-04	O
2010-10-01	O
Optimization	O
on	O
JOINs	B-Language
and	O
data	O
warehouse	O
functions	O
8.0	O
2005-01-19	O
2010-10-04	O
2010-10-01	O
Native	O
server	O
on	O
Microsoft	B-Application
Windows	I-Application
,	O
savepoints	B-General_Concept
,	O
tablespaces	B-General_Concept
,	O
point-in-time	B-General_Concept
recovery	I-General_Concept
8.1	O
2005-11-08	O
2010-12-16	O
2010-11-08	O
Performance	O
optimization	O
,	O
two-phase	B-General_Concept
commit	I-General_Concept
,	O
table	O
partitioning	B-General_Concept
,	O
index	O
bitmap	O
scan	O
,	O
shared	O
row	O
locking	O
,	O
roles	O
8.2	O
2006-12-05	O
2011-12-05	O
2011-12-05	O
Performance	O
optimization	O
,	O
online	O
index	O
builds	O
,	O
advisory	O
locks	O
,	O
warm	O
standby	O
8.3	O
2008-02-04	O
2013-02-07	O
2013-02-07	O
Heap-only	O
tuples	O
,	O
full	B-Application
text	I-Application
search	I-Application
,	O
SQL/XML	B-Language
,	O
ENUM	O
types	O
,	O
UUID	O
types	O
8.4	O
2009-07-01	O
2014-07-24	O
2014-07-24	O
Windowing	O
functions	O
,	O
column-level	O
permissions	O
,	O
parallel	O
database	O
restore	O
,	O
per-database	O
collation	O
,	O
common	O
table	O
expressions	O
and	O
recursive	O
queries	B-Language
9.0	O
2010-09-20	O
2015-10-08	O
2015-10-08	O
Built-in	O
binary	O
streaming	O
replication	B-Architecture
,	O
hot	B-General_Concept
standby	I-General_Concept
,	O
in-place	O
upgrade	O
ability	O
,	O
64-bit	B-Device
Windows	B-Application
9.1	O
2011-09-12	O
2016-10-27	O
2016-10-27	O
Synchronous	O
replication	B-Architecture
,	O
per-column	O
collations	O
,	O
unlogged	O
tables	O
,	O
serializable	B-Operating_System
snapshot	B-Operating_System
isolation	I-Operating_System
,	O
writeable	O
common	O
table	O
expressions	O
,	O
SELinux	B-Application
integration	O
,	O
extensions	O
,	O
foreign	O
tables	O
9.2	O
2012-09-10	O
2017-11-09	O
2017-11-09	O
Cascading	O
streaming	O
replication	B-Architecture
,	O
index-only	O
scans	O
,	O
native	O
JSON	B-General_Concept
support	O
,	O
improved	O
lock	O
management	O
,	O
range	O
types	O
,	O
pg_receivexlog	O
tool	O
,	O
space-partitioned	O
GiST	B-Device
indexes	O
9.3	O
2013-09-09	O
2018-11-08	O
2018-11-08	O
Custom	O
background	O
workers	O
,	O
data	O
checksums	O
,	O
dedicated	O
JSON	B-General_Concept
operators	O
,	O
LATERAL	O
JOIN	O
,	O
faster	O
pg_dump	O
,	O
new	O
pg_isready	O
server	O
monitoring	O
tool	O
,	O
trigger	O
features	O
,	O
view	B-Language
features	O
,	O
writeable	O
foreign	O
tables	O
,	O
materialized	B-Application
views	I-Application
,	O
replication	B-Architecture
improvements	O
9.4	O
2014-12-18	O
2020-02-13	O
2020-02-13	O
JSONB	O
data	O
type	O
,	O
ALTER	O
SYSTEM	O
statement	O
for	O
changing	O
config	O
values	O
,	O
ability	O
to	O
refresh	O
materialized	B-Application
views	I-Application
without	O
blocking	O
reads	O
,	O
dynamic	O
registration/start/stop	O
of	O
background	O
worker	O
processes	O
,	O
Logical	O
Decoding	O
API	O
,	O
GiN	O
index	O
improvements	O
,	O
Linux	B-Application
huge	O
page	O
support	O
,	O
database	O
cache	O
reloading	O
via	O
pg_prewarm	O
,	O
reintroducing	O
Hstore	O
as	O
the	O
column	O
type	O
of	O
choice	O
for	O
document-style	O
data	O
.	O
</s>
<s>
9.5	O
2016-01-07	O
2021-02-11	O
2021-02-11	O
UPSERT	B-Language
,	O
row	O
level	O
security	O
,	O
TABLESAMPLE	O
,	O
CUBE/ROLLUP	O
,	O
GROUPING	O
SETS	O
,	O
and	O
new	O
BRIN	B-Language
index	O
9.6	O
2016-09-29	O
2021-11-11	O
2021-11-11	O
Parallel	O
query	B-Language
support	O
,	O
PostgreSQL	B-Application
foreign	O
data	O
wrapper	O
(	O
FDW	O
)	O
improvements	O
with	O
sort/join	O
pushdown	O
,	O
multiple	O
synchronous	O
standbys	O
,	O
faster	O
vacuuming	O
of	O
large	O
table	O
10	O
2017-10-05	O
2022-11-10	O
2022-11-10	O
Logical	O
replication	B-Architecture
,	O
declarative	O
table	O
partitioning	B-General_Concept
,	O
improved	O
query	B-Language
parallelism	O
11	O
2018-10-18	O
2023-02-09	O
2023-11-09	O
Increased	O
robustness	O
and	O
performance	O
for	O
partitioning	B-General_Concept
,	O
transactions	B-General_Concept
supported	O
in	O
stored	B-General_Concept
procedures	I-General_Concept
,	O
enhanced	O
abilities	O
for	O
query	B-Language
parallelism	O
,	O
just-in-time	O
(	O
JIT	O
)	O
compiling	O
for	O
expressions	O
12	O
2019-10-03	O
2023-02-09	O
2024-11-14	O
Improvements	O
to	O
query	B-Language
performance	O
and	O
space	O
utilization	O
;	O
SQL/JSON	O
path	O
expression	O
support	O
;	O
generated	O
columns	O
;	O
improvements	O
to	O
internationalization	B-General_Concept
,	O
and	O
authentication	O
;	O
new	O
pluggable	O
table	O
storage	O
interface	O
.	O
</s>
<s>
13	O
2020-09-24	O
2023-02-09	O
2025-11-13	O
Space	O
savings	O
and	O
performance	O
gains	O
from	O
de-duplication	O
of	O
B-tree	B-Architecture
index	O
entries	O
,	O
improved	O
performance	O
for	O
queries	B-Language
that	O
use	O
aggregates	O
or	O
partitioned	O
tables	O
,	O
better	O
query	B-Language
planning	O
when	O
using	O
extended	O
statistics	O
,	O
parallelized	O
vacuuming	O
of	O
indexes	O
,	O
incremental	O
sorting	O
14	O
2021-09-30	O
2023-02-09	O
2026-11-12	O
Added	O
SQL-standard	O
SEARCH	O
and	O
CYCLE	O
clauses	O
for	O
common	O
table	O
expressions	O
,	O
allow	O
DISTINCT	O
to	O
be	O
added	O
to	O
GROUP	O
BY	O
15	O
2022-10-13	O
2023-02-09	O
2027-11-11	O
Implements	O
SQL-standard	O
MERGE	B-Language
statement	O
.	O
</s>
<s>
PL/Python	O
now	O
only	O
supports	O
current	O
,	O
and	O
now	O
means	O
,	O
no	O
longer	O
the	O
discontinued	O
.	O
</s>
