<s>
Couchbase	B-Operating_System
Server	I-Operating_System
,	O
originally	O
known	O
as	O
Membase	B-Operating_System
,	O
is	O
an	O
open-source	B-Application
,	O
distributed	O
(	O
shared-nothing	B-Operating_System
architecture	I-Operating_System
)	O
multi-model	B-Operating_System
NoSQL	B-General_Concept
document-oriented	B-General_Concept
database	I-General_Concept
software	O
package	O
optimized	O
for	O
interactive	O
applications	O
.	O
</s>
<s>
These	O
applications	O
may	O
serve	O
many	O
concurrent	B-License
users	I-License
by	O
creating	O
,	O
storing	O
,	O
retrieving	O
,	O
aggregating	O
,	O
manipulating	O
and	O
presenting	O
data	O
.	O
</s>
<s>
In	O
support	O
of	O
these	O
kinds	O
of	O
application	O
needs	O
,	O
Couchbase	B-Operating_System
Server	I-Operating_System
is	O
designed	O
to	O
provide	O
easy-to-scale	O
key-value	O
,	O
or	O
JSON	B-General_Concept
document	O
access	O
,	O
with	O
low	O
latency	O
and	O
high	O
sustainability	O
throughput	O
.	O
</s>
<s>
It	O
is	O
designed	O
to	O
be	O
clustered	B-Architecture
from	O
a	O
single	O
machine	O
to	O
very	O
large-scale	O
deployments	O
spanning	O
many	O
machines	O
.	O
</s>
<s>
Couchbase	B-Operating_System
Server	I-Operating_System
provided	O
client	O
protocol	O
compatibility	O
with	O
memcached	B-Application
,	O
but	O
added	O
disk	O
persistence	B-Application
,	O
data	B-Architecture
replication	I-Architecture
,	O
live	O
cluster	O
reconfiguration	O
,	O
rebalancing	O
and	O
multitenancy	B-Architecture
with	O
data	B-General_Concept
partitioning	I-General_Concept
.	O
</s>
<s>
Membase	B-Operating_System
was	O
developed	O
by	O
several	O
leaders	O
of	O
the	O
memcached	B-Application
project	O
,	O
who	O
had	O
founded	O
a	O
company	O
,	O
NorthScale	O
,	O
to	O
develop	O
a	O
key-value	B-Data_Structure
store	I-Data_Structure
with	O
the	O
simplicity	O
,	O
speed	O
,	O
and	O
scalability	O
of	O
memcached	B-Application
,	O
but	O
also	O
the	O
storage	O
,	O
persistence	B-Application
and	O
querying	O
capabilities	O
of	O
a	O
database	O
.	O
</s>
<s>
The	O
original	O
membase	B-Operating_System
source	O
code	O
was	O
contributed	O
by	O
NorthScale	O
,	O
and	O
project	O
co-sponsors	O
Zynga	O
and	O
Naver	O
Corporation	O
(	O
then	O
known	O
as	O
NHN	O
)	O
to	O
a	O
new	O
project	O
on	O
membase.org	O
in	O
June	O
2010	O
.	O
</s>
<s>
On	O
February	O
8	O
,	O
2011	O
,	O
the	O
Membase	B-Operating_System
project	O
founders	O
and	O
Membase	B-Operating_System
,	O
Inc	O
.	O
announced	O
a	O
merger	O
with	O
CouchOne	O
(	O
a	O
company	O
with	O
many	O
of	O
the	O
principal	O
players	O
behind	O
CouchDB	B-Application
)	O
with	O
an	O
associated	O
project	O
merger	O
.	O
</s>
<s>
The	O
merged	O
company	O
was	O
called	O
Couchbase	B-General_Concept
,	I-General_Concept
Inc	I-General_Concept
.	I-General_Concept
</s>
<s>
In	O
January	O
2012	O
,	O
Couchbase	B-Operating_System
released	O
Couchbase	B-Operating_System
Server	I-Operating_System
1.8	O
.	O
</s>
<s>
In	O
September	O
of	O
2012	O
,	O
Orbitz	O
said	O
it	O
had	O
changed	O
some	O
of	O
its	O
systems	O
to	O
use	O
Couchbase	B-Operating_System
.	O
</s>
<s>
In	O
December	O
of	O
2012	O
,	O
Couchbase	B-Operating_System
Server	I-Operating_System
2.0	O
(	O
announced	O
in	O
July	O
2011	O
)	O
was	O
released	O
and	O
included	O
a	O
new	O
JSON	B-General_Concept
document	B-General_Concept
store	I-General_Concept
,	O
indexing	O
and	O
querying	O
,	O
incremental	O
MapReduce	B-Operating_System
and	O
replication	B-Architecture
across	O
data	B-Operating_System
centers	I-Operating_System
.	O
</s>
<s>
Every	O
Couchbase	B-Operating_System
node	O
consists	O
of	O
a	O
data	O
service	O
,	O
index	O
service	O
,	O
query	O
service	O
,	O
and	O
cluster	O
manager	O
component	O
.	O
</s>
<s>
In	O
the	O
parlance	O
of	O
Eric	O
Brewer	O
's	O
CAP	B-Operating_System
theorem	I-Operating_System
,	O
Couchbase	B-Operating_System
is	O
normally	O
a	O
CP	O
type	O
system	O
meaning	O
it	O
provides	O
consistency	B-General_Concept
and	O
partition	B-Algorithm
tolerance	I-Algorithm
,	O
or	O
it	O
can	O
be	O
set	O
up	O
as	O
an	O
AP	O
system	O
with	O
multiple	O
clusters	O
.	O
</s>
<s>
The	O
cluster	O
manager	O
supervises	O
the	O
configuration	O
and	O
behavior	O
of	O
all	O
the	O
servers	O
in	O
a	O
Couchbase	B-Operating_System
cluster	O
.	O
</s>
<s>
It	O
configures	O
and	O
supervises	O
inter-node	O
behavior	O
like	O
managing	O
replication	B-Architecture
streams	O
and	O
re-balancing	O
operations	O
.	O
</s>
<s>
The	O
cluster	O
manager	O
uses	O
the	O
Erlang	B-Operating_System
programming	I-Operating_System
language	I-Operating_System
and	O
the	O
Open	B-Language
Telecom	I-Language
Platform	I-Language
.	O
</s>
<s>
Data	B-Architecture
replication	I-Architecture
within	O
the	O
nodes	O
of	O
a	O
cluster	O
can	O
be	O
controlled	O
with	O
several	O
parameters	O
.	O
</s>
<s>
In	O
December	O
of	O
2012	O
,	O
support	O
was	O
added	O
for	O
replication	B-Architecture
between	O
different	O
data	B-Operating_System
centers	I-Operating_System
.	O
</s>
<s>
External	O
systems	O
can	O
subscribe	O
to	O
filtered	O
data	O
streams	O
,	O
supporting	O
,	O
for	O
example	O
,	O
full	B-Application
text	I-Application
search	I-Application
indexing	O
,	O
data	B-General_Concept
analytics	I-General_Concept
or	O
archiving	O
.	O
</s>
<s>
A	O
document	O
is	O
the	O
most	O
basic	O
unit	O
of	O
data	O
manipulation	O
in	O
Couchbase	B-Operating_System
Server	I-Operating_System
.	O
</s>
<s>
Documents	O
are	O
stored	O
in	O
JSON	B-General_Concept
document	O
format	O
with	O
no	O
predefined	O
schemas	O
.	O
</s>
<s>
Non-JSON	O
documents	O
can	O
also	O
be	O
stored	O
in	O
Couchbase	B-Operating_System
Server	I-Operating_System
(	O
binary	O
,	O
serialized	O
values	O
,	O
XML	O
,	O
etc	O
.	O
)	O
</s>
<s>
Couchbase	B-Operating_System
Server	I-Operating_System
includes	O
a	O
built-in	O
multi-threaded	O
object-managed	O
cache	B-General_Concept
that	O
implements	O
memcached	B-Application
compatible	O
APIs	O
such	O
as	O
get	O
,	O
set	O
,	O
delete	O
,	O
append	O
,	O
prepend	O
etc	O
.	O
</s>
<s>
Couchbase	B-Operating_System
Server	I-Operating_System
has	O
a	O
tail-append	O
storage	O
design	O
that	O
is	O
immune	O
to	O
data	O
corruption	O
,	O
OOM	B-General_Concept
killers	I-General_Concept
or	O
sudden	O
loss	O
of	O
power	O
.	O
</s>
<s>
Data	O
is	O
written	O
to	O
the	O
data	O
file	O
in	O
an	O
append-only	O
manner	O
,	O
which	O
enables	O
Couchbase	B-Operating_System
to	O
do	O
mostly	O
sequential	O
writes	O
for	O
update	O
,	O
and	O
provide	O
an	O
optimized	O
access	O
patterns	O
for	O
disk	O
I/O	O
.	O
</s>
<s>
A	O
performance	O
benchmark	O
done	O
by	O
Altoros	O
in	O
2012	O
,	O
compared	O
Couchbase	B-Operating_System
Server	I-Operating_System
with	O
other	O
technologies	O
.	O
</s>
<s>
Cisco	O
Systems	O
published	O
a	O
benchmark	O
that	O
measured	O
the	O
latency	O
and	O
throughput	O
of	O
Couchbase	B-Operating_System
Server	I-Operating_System
with	O
a	O
mixed	O
workload	O
in	O
2012	O
.	O
</s>
<s>
Couchbase	B-Operating_System
Server	I-Operating_System
is	O
a	O
packaged	O
version	O
of	O
Couchbase	B-Operating_System
's	O
open	B-Application
source	I-Application
software	I-Application
technology	O
and	O
is	O
available	O
in	O
a	O
community	O
edition	O
without	O
recent	O
bug	O
fixes	O
with	O
an	O
Apache	O
2.0	O
license	O
and	O
an	O
edition	O
for	O
commercial	O
use	O
.	O
</s>
<s>
Couchbase	B-Operating_System
Server	I-Operating_System
builds	O
are	O
available	O
for	O
Ubuntu	O
,	O
Debian	O
,	O
Red	O
Hat	O
,	O
SUSE	O
,	O
Oracle	B-General_Concept
Linux	O
,	O
Microsoft	B-Application
Windows	I-Application
and	O
macOS	O
operating	O
systems	O
.	O
</s>
<s>
Couchbase	B-Operating_System
has	O
supported	O
software	O
developers	O
 '	O
kits	O
for	O
the	O
programming	O
languages	O
.NET	B-Application
,	O
PHP	B-Application
,	O
Ruby	B-Language
,	O
Python	B-Language
,	O
C	B-Language
,	O
Node.js	B-Language
,	O
Java	B-Language
,	O
Go	B-Application
,	O
and	O
Scala	B-Application
.	O
</s>
<s>
A	O
query	B-Language
language	I-Language
called	O
the	O
non-first	O
normal	B-Application
form	I-Application
query	B-Language
language	I-Language
,	O
N1QL	B-Operating_System
(	O
pronounced	O
nickel	O
)	O
,	O
is	O
used	O
for	O
manipulating	O
the	O
JSON	B-General_Concept
data	O
in	O
Couchbase	B-Operating_System
,	O
just	O
like	O
SQL	O
manipulates	O
data	O
in	O
RDBMS	O
.	O
</s>
<s>
It	O
has	O
SELECT	O
,	O
INSERT	O
,	O
UPDATE	O
,	O
DELETE	O
,	O
MERGE	O
statements	O
to	O
operate	O
on	O
JSON	B-General_Concept
data	O
.	O
</s>
<s>
The	O
N1QL	B-Operating_System
data	B-Application
model	I-Application
is	O
non-first	O
normal	B-Application
form	I-Application
(	O
N1NF	O
)	O
with	O
support	O
for	O
nested	O
attributes	O
and	O
domain-oriented	O
normalization	B-Application
.	O
</s>
<s>
The	O
N1QL	B-Operating_System
data	B-Application
model	I-Application
is	O
also	O
a	O
proper	O
superset	O
and	O
generalization	O
of	O
the	O
relational	B-Architecture
model	I-Architecture
.	O
</s>
<s>
Couchbase	B-Operating_System
Mobile	O
/	O
Couchbase	B-Operating_System
Lite	I-Operating_System
is	O
a	O
mobile	O
database	O
providing	O
data	B-Architecture
replication	I-Architecture
.	O
</s>
<s>
Couchbase	B-Operating_System
Lite	I-Operating_System
(	O
originally	O
TouchDB	O
)	O
provides	O
native	O
libraries	O
for	O
offline-first	O
NoSQL	B-General_Concept
databases	O
with	O
built-in	O
peer-to-peer	O
or	O
client-server	B-Operating_System
replication	B-Architecture
mechanisms	O
.	O
</s>
<s>
Sync	O
Gateway	O
manages	O
secure	O
access	O
and	O
synchronization	O
of	O
data	O
between	O
Couchbase	B-Operating_System
Lite	I-Operating_System
and	O
Couchbase	B-Operating_System
Server	I-Operating_System
.	O
</s>
<s>
Couchbase	B-Operating_System
began	O
as	O
an	O
evolution	O
of	O
Memcached	B-Application
,	O
a	O
high-speed	O
data	O
cache	B-General_Concept
,	O
and	O
can	O
be	O
used	O
as	O
a	O
drop-in	O
replacement	O
for	O
Memcached	B-Application
,	O
providing	O
high	O
availability	O
for	O
memcached	B-Application
application	O
without	O
code	O
changes	O
.	O
</s>
<s>
Couchbase	B-Operating_System
is	O
used	O
to	O
support	O
applications	O
where	O
a	O
flexible	O
data	B-Application
model	I-Application
,	O
easy	O
scalability	O
,	O
and	O
consistent	O
high	O
performance	O
are	O
required	O
,	O
such	O
as	O
tracking	O
real-time	O
user	O
activity	O
or	O
providing	O
a	O
store	O
of	O
user	O
preferences	O
or	O
online	O
applications	O
.	O
</s>
<s>
Couchbase	B-Operating_System
Mobile	O
,	O
which	O
stores	O
data	O
locally	O
on	O
devices	O
(	O
usually	O
mobile	O
devices	O
)	O
is	O
used	O
to	O
create	O
“	O
offline-first	O
”	O
applications	O
that	O
can	O
operate	O
when	O
a	O
device	O
is	O
not	O
connected	O
to	O
a	O
network	O
and	O
synchronize	O
with	O
Couchbase	B-Operating_System
Server	I-Operating_System
once	O
a	O
network	O
connection	O
is	O
re-established	O
.	O
</s>
<s>
The	O
Catalyst	O
Lab	O
at	O
Northwestern	O
University	O
uses	O
Couchbase	B-Operating_System
Mobile	O
to	O
support	O
the	O
Evo	O
application	O
,	O
a	O
healthy	O
lifestyle	O
research	O
program	O
where	O
data	O
is	O
used	O
to	O
help	O
participants	O
improve	O
dietary	O
quality	O
,	O
physical	O
activity	O
,	O
stress	O
,	O
or	O
sleep	O
.	O
</s>
<s>
Amadeus	O
uses	O
Couchbase	B-Operating_System
with	O
Apache	B-Language
Kafka	I-Language
to	O
support	O
their	O
“	O
open	O
,	O
simple	O
,	O
and	O
agile	O
”	O
strategy	O
to	O
consume	O
and	O
integrate	O
data	O
on	O
loyalty	O
programs	O
for	O
airline	O
and	O
other	O
travel	O
partners	O
.	O
</s>
<s>
Starting	O
in	O
2012	O
,	O
it	O
played	O
a	O
role	O
in	O
LinkedIn	B-Application
's	O
caching	B-General_Concept
systems	O
,	O
including	O
backend	B-Architecture
caching	B-General_Concept
for	O
recruiter	O
and	O
jobs	O
products	O
,	O
counters	O
for	O
security	O
defense	O
mechanisms	O
,	O
for	O
internal	O
applications	O
.	O
</s>
<s>
For	O
caching	B-General_Concept
,	O
Couchbase	B-Operating_System
competes	O
with	O
Memcached	B-Application
and	O
Redis	B-Operating_System
.	O
</s>
<s>
For	O
document	B-General_Concept
databases	I-General_Concept
,	O
Couchbase	B-Operating_System
competes	O
with	O
other	O
document-oriented	B-General_Concept
database	I-General_Concept
systems	O
.	O
</s>
<s>
It	O
is	O
commonly	O
compared	O
with	O
MongoDB	B-Application
,	O
Amazon	B-Application
DynamoDB	I-Application
,	O
Oracle	B-General_Concept
RDBMS	I-General_Concept
,	O
DataStax	B-General_Concept
,	O
Google	B-Application
Bigtable	I-Application
,	O
MariaDB	B-Application
,	O
IBM	B-General_Concept
Cloudant	I-General_Concept
,	O
Redis	B-Operating_System
Enterprise	I-Operating_System
,	O
SingleStore	B-Application
,	O
and	O
MarkLogic	B-Application
.	O
</s>
