<s>
YugabyteDB	B-Operating_System
is	O
a	O
high-performance	O
transactional	B-General_Concept
distributed	B-Language
SQL	I-Language
database	O
for	O
cloud-native	B-General_Concept
applications	O
,	O
developed	O
by	O
Yugabyte	B-Operating_System
.	O
</s>
<s>
Yugabyte	B-Operating_System
was	O
founded	O
by	O
ex-Facebook	O
engineers	O
Kannan	O
Muthukkaruppan	O
,	O
Karthik	O
Ranganathan	O
,	O
and	O
Mikhail	O
Bautin	O
.	O
</s>
<s>
At	O
Facebook	B-Application
,	O
they	O
were	O
part	O
of	O
the	O
team	O
that	O
built	O
and	O
operated	O
Cassandra	B-Application
and	O
HBase	B-Language
during	O
a	O
period	O
of	O
significant	O
growth	O
in	O
workloads	O
such	O
as	O
Facebook	B-Protocol
Messenger	I-Protocol
and	O
Facebook	B-Application
's	O
Operational	O
Data	O
Store	O
.	O
</s>
<s>
The	O
founders	O
came	O
together	O
in	O
February	O
2016	O
to	O
build	O
YugabyteDB	B-Operating_System
,	O
believing	O
that	O
the	O
trends	O
they	O
experienced	O
at	O
Facebook	B-Application
–	O
microservices	O
,	O
containerization	B-General_Concept
,	O
high	B-General_Concept
availability	I-General_Concept
,	O
geographic	O
distribution	O
,	O
APIs	B-General_Concept
,	O
and	O
open-source	B-Application
–	O
were	O
relevant	O
to	O
all	O
businesses	O
,	O
especially	O
as	O
they	O
move	O
from	O
on-premise	O
to	O
cloud-native	B-General_Concept
operations	O
.	O
</s>
<s>
YugabyteDB	B-Operating_System
was	O
initially	O
available	O
in	O
two	O
editions	O
:	O
community	O
and	O
enterprise	O
.	O
</s>
<s>
In	O
July	O
2019	O
,	O
Yugabyte	B-Operating_System
open	O
sourced	O
previously	O
commercial	O
features	O
and	O
launched	O
YugabyteDB	B-Operating_System
as	O
open-source	B-Application
under	O
the	O
Apache	B-Application
2.0	I-Application
license	I-Application
.	O
</s>
<s>
Yugabyte	B-Operating_System
launched	O
Yugabyte	B-Operating_System
Cloud	O
,	O
now	O
renamed	O
YugabyteDB	B-Operating_System
Managed	O
,	O
a	O
fully	O
managed	O
database-as-a-service	O
offering	O
of	O
YugabyteDB	B-Operating_System
,	O
in	O
September	O
2021	O
.	O
</s>
<s>
YugabyteDB	B-Operating_System
is	O
a	O
distributed	B-Language
SQL	I-Language
database	O
that	O
aims	O
to	O
be	O
strongly	O
transactionally	O
consistent	O
across	O
failure	O
zones	O
(	O
i.e.	O
</s>
<s>
In	O
CAP	B-Operating_System
Theorem	I-Operating_System
terms	O
YugabyteDB	B-Operating_System
is	O
a	O
Consistent/Partition	O
Tolerant	O
(	O
CP	O
)	O
database	O
.	O
</s>
<s>
YugabyteDB	B-Operating_System
has	O
two	O
layers	O
,	O
a	O
storage	O
engine	O
known	O
as	O
DocDB	O
and	O
the	O
Yugabyte	B-Operating_System
Query	O
Layer	O
.	O
</s>
<s>
The	O
storage	O
engine	O
consists	O
of	O
a	O
customized	O
RocksDB	B-Language
combined	O
with	O
sharding	O
and	O
load	O
balancing	O
algorithms	O
for	O
the	O
data	O
.	O
</s>
<s>
In	O
addition	O
,	O
the	O
Raft	B-Operating_System
consensus	I-Operating_System
algorithm	I-Operating_System
controls	O
the	O
replication	O
of	O
data	O
between	O
the	O
nodes	O
.	O
</s>
<s>
There	O
is	O
also	O
a	O
Distributed	B-General_Concept
transaction	I-General_Concept
manager	O
and	O
Multiversion	B-Operating_System
concurrency	I-Operating_System
control	I-Operating_System
(	O
MVCC	O
)	O
to	O
support	O
distributed	B-General_Concept
transactions	I-General_Concept
.	O
</s>
<s>
The	O
engine	O
also	O
exploits	O
a	O
Hybrid	O
Logical	O
Clock	O
that	O
combines	O
coarsely-synchronized	O
physical	O
clocks	O
with	O
Lamport	B-Operating_System
clocks	I-Operating_System
to	O
track	O
causal	O
relationships	O
.	O
</s>
<s>
Yugabyte	B-Operating_System
has	O
a	O
pluggable	O
query	O
layer	O
that	O
abstracts	O
the	O
query	O
layer	O
from	O
the	O
storage	O
layer	O
below	O
.	O
</s>
<s>
There	O
are	O
currently	O
two	O
APIs	B-General_Concept
that	O
can	O
access	O
the	O
database	O
:	O
</s>
<s>
YSQL	O
is	O
a	O
PostgreSQL	O
code-compatible	O
API	B-General_Concept
based	O
around	O
v11.2	O
.	O
</s>
<s>
This	O
re-use	O
means	O
that	O
Yugabyte	B-Operating_System
supports	O
many	O
features	O
,	O
including	O
:	O
</s>
<s>
YCQL	O
is	O
a	O
Cassandra-like	O
API	B-General_Concept
based	O
around	O
v3.10	O
and	O
re-written	O
in	O
C++	B-Language
.	O
</s>
<s>
YCQL	O
is	O
accessed	O
via	O
standard	O
Cassandra	B-Application
drivers	O
using	O
the	O
native	O
protocol	O
port	O
of	O
9042	O
.	O
</s>
<s>
In	O
addition	O
to	O
the	O
'	O
vanilla	O
 '	O
Cassandra	B-Application
components	O
,	O
YCQL	O
is	O
augmented	O
with	O
the	O
following	O
features	O
:	O
</s>
<s>
Transactional	B-General_Concept
consistency	O
-	O
unlike	O
Cassandra	B-Application
,	O
Yugabyte	B-Operating_System
YCQL	O
is	O
transactional	B-General_Concept
.	O
</s>
<s>
Currently	O
,	O
data	O
written	O
to	O
either	O
API	B-General_Concept
is	O
not	O
accessible	O
via	O
the	O
other	O
API	B-General_Concept
,	O
however	O
YSQL	O
can	O
access	O
YCQL	O
using	O
the	O
PostgreSQL	O
foreign	O
data	O
wrapper	O
feature	O
.	O
</s>
<s>
The	O
security	O
model	O
for	O
accessing	O
the	O
system	O
is	O
inherited	O
from	O
the	O
API	B-General_Concept
,	O
so	O
access	O
controls	O
for	O
YSQL	O
look	O
like	O
PostgreSQL	O
,	O
and	O
YCQL	O
looks	O
like	O
Cassandra	B-Application
access	O
controls	O
.	O
</s>
<s>
In	O
addition	O
to	O
its	O
core	O
functionality	O
of	O
distributing	O
a	O
single	O
database	O
,	O
YugabyteDB	B-Operating_System
has	O
the	O
ability	O
to	O
replicate	O
between	O
database	B-Application
instances	I-Application
.	O
</s>
<s>
Yugabyte	B-Operating_System
also	O
provides	O
YugabyteDB	B-Operating_System
Voyager	O
,	O
tooling	O
to	O
facilitate	O
the	O
migration	O
of	O
Oracle	O
and	O
other	O
similar	O
databases	B-Application
to	O
YugabyteDB	B-Operating_System
.	O
</s>
<s>
This	O
tool	O
supports	O
the	O
migration	O
of	O
schemas	O
,	O
procedural	O
code	O
and	O
data	O
from	O
the	O
source	O
platform	O
to	O
YugabyteDB	B-Operating_System
.	O
</s>
