<s>
RocksDB	B-Language
is	O
a	O
high	O
performance	O
embedded	B-Application
database	I-Application
for	O
key-value	B-Data_Structure
data	O
.	O
</s>
<s>
It	O
is	O
a	O
fork	O
of	O
Google	O
's	O
LevelDB	B-Language
optimized	O
to	O
exploit	O
many	O
CPU	B-Architecture
cores	I-Architecture
,	O
and	O
make	O
efficient	O
use	O
of	O
fast	O
storage	O
,	O
such	O
as	O
solid-state	B-Device
drives	I-Device
(	O
SSD	B-Device
)	O
,	O
for	O
input/output	O
(	O
I/O	O
)	O
bound	O
workloads	O
.	O
</s>
<s>
It	O
is	O
based	O
on	O
a	O
log-structured	B-Data_Structure
merge-tree	I-Data_Structure
(	O
LSM	O
tree	O
)	O
data	O
structure	O
.	O
</s>
<s>
It	O
is	O
written	O
in	O
C++	B-Language
and	O
provides	O
official	O
language	B-Application
bindings	I-Application
for	O
C++	B-Language
,	O
C	B-Language
,	O
and	O
Java	B-Language
;	O
alongside	O
many	O
third-party	O
language	B-Application
bindings	I-Application
.	O
</s>
<s>
RocksDB	B-Language
is	O
open-source	B-Application
software	I-Application
,	O
and	O
was	O
originally	O
released	O
under	O
a	O
BSD	B-Operating_System
3-clause	I-Operating_System
license	O
.	O
</s>
<s>
RocksDB	B-Language
is	O
used	O
in	O
production	O
systems	O
at	O
various	O
web-scale	B-Architecture
enterprises	O
including	O
Facebook	B-Application
,	O
Yahoo	O
!,	O
and	O
LinkedIn	B-Application
.	O
</s>
<s>
RocksDB	B-Language
,	O
like	O
LevelDB	B-Language
,	O
stores	O
keys	O
and	O
values	O
in	O
arbitrary	O
byte	O
arrays	O
,	O
and	O
data	O
is	O
sorted	O
byte-wise	O
by	O
key	O
or	O
by	O
providing	O
a	O
custom	O
comparator	O
.	O
</s>
<s>
RocksDB	B-Language
provides	O
all	O
of	O
the	O
features	O
of	O
LevelDB	B-Language
,	O
plus	O
:	O
</s>
<s>
RocksDB	B-Language
is	O
not	O
an	O
SQL	B-Language
database	I-Language
(	O
although	O
MyRocks	B-Language
combines	O
RocksDB	B-Language
with	O
MySQL	B-Application
)	O
.	O
</s>
<s>
Like	O
other	O
NoSQL	B-General_Concept
and	O
dbm	B-General_Concept
stores	O
,	O
it	O
has	O
no	O
relational	O
data	O
model	O
,	O
and	O
it	O
does	O
not	O
support	O
SQL	B-Language
queries	O
.	O
</s>
<s>
Also	O
,	O
it	O
has	O
no	O
direct	O
support	O
for	O
secondary	O
indexes	O
,	O
however	O
a	O
user	O
may	O
build	O
their	O
own	O
internally	O
using	O
Column	B-Application
Families	I-Application
or	O
externally	O
.	O
</s>
<s>
Applications	O
use	O
RocksDB	B-Language
as	O
a	O
library	O
,	O
as	O
it	O
does	O
not	O
provide	O
a	O
server	O
or	O
command-line	O
interface	O
.	O
</s>
<s>
RocksDB	B-Language
was	O
created	O
at	O
Facebook	B-Application
by	O
Dhruba	O
Borthakur	O
in	O
April	O
2012	O
,	O
as	O
a	O
fork	O
of	O
LevelDB	B-Language
with	O
the	O
initial	O
stated	O
goal	O
of	O
improving	O
performance	O
for	O
server	O
workloads	O
.	O
</s>
<s>
As	O
an	O
embeddable	O
database	O
,	O
RocksDB	B-Language
can	O
be	O
used	O
as	O
a	O
storage	O
engine	O
within	O
a	O
larger	O
database	O
management	O
system	O
(	O
DBMS	B-General_Concept
)	O
.	O
</s>
<s>
For	O
example	O
,	O
Rockset	O
uses	O
RocksDB	B-Language
mostly	O
for	O
analytical	O
data	O
processing	O
.	O
</s>
<s>
The	O
following	O
projects	O
have	O
been	O
started	O
to	O
replace	O
or	O
offer	O
alternative	O
storage	O
engines	O
for	O
already-established	O
database	O
systems	O
with	O
RocksDB	B-Language
:	O
</s>
<s>
ArangoDB	B-Operating_System
has	O
added	O
RocksDB	B-Language
to	O
its	O
previous	O
storage	O
engine	O
(	O
"	O
mmfiles	O
"	O
)	O
.	O
</s>
<s>
Starting	O
with	O
ArangoDB	B-Operating_System
3.4	O
,	O
RocksDB	B-Language
will	O
be	O
the	O
default	O
storage	O
engine	O
in	O
ArangoDB	B-Operating_System
.	O
</s>
<s>
Cassandra	B-Application
on	O
RocksDB	B-Language
can	O
improve	O
the	O
performance	O
of	O
Apache	B-Application
Cassandra	I-Application
significantly	O
(	O
3-4	O
times	O
faster	O
in	O
general	O
,	O
100	O
times	O
faster	O
in	O
some	O
use-cases	O
)	O
.	O
</s>
<s>
The	O
Instagram	O
team	O
at	O
Facebook	B-Application
developed	O
and	O
open-sourced	O
their	O
code	O
,	O
along	O
with	O
benchmarks	O
of	O
their	O
performance	O
results	O
.	O
</s>
<s>
MariaDB	B-Application
can	O
use	O
the	O
MyRocks	B-Language
storage	O
engine	O
(	O
which	O
is	O
forked	O
from	O
RocksDB	B-Language
)	O
since	O
MariaDB	B-Application
10.2.5	O
(	O
Alpha	O
status	O
)	O
and	O
stable	O
since	O
MariaDB	B-Application
10.2.16	O
in	O
2018	O
.	O
</s>
<s>
The	O
MongoRocks	O
project	O
provides	O
a	O
storage	O
module	O
for	O
MongoDB	B-Application
where	O
the	O
storage	O
engine	O
is	O
RocksDB	B-Language
.	O
</s>
<s>
A	O
related	O
program	O
is	O
Rocks	O
Strata	O
,	O
a	O
tool	O
written	O
in	O
Go	B-Application
,	O
which	O
allows	O
managing	O
incremental	O
backups	B-Protocol
of	O
MongoDB	B-Application
when	O
RocksDB	B-Language
is	O
used	O
as	O
the	O
storage	O
engine	O
.	O
</s>
<s>
The	O
MyRocks	B-Language
project	O
creates	O
a	O
new	O
RocksDB-based	O
storage	O
engine	O
for	O
MySQL	B-Application
.	O
</s>
<s>
In-depth	O
details	O
about	O
MyRocks	B-Language
were	O
presented	O
at	O
Percona	O
Live	O
2016	O
.	O
</s>
<s>
The	O
UKV	O
project	O
allows	O
users	O
to	O
use	O
RocksDB	B-Language
on	O
par	O
with	O
LevelDB	B-Language
as	O
the	O
underlying	O
Key-Value	B-Data_Structure
Store	I-Data_Structure
.	O
</s>
<s>
It	O
augments	O
it	O
with	O
structured	O
bindings	O
for	O
several	O
high-level	O
languages	O
,	O
like	O
Python	B-Language
,	O
Java	B-Language
,	O
and	O
Go	B-Application
.	O
</s>
<s>
The	O
following	O
database	O
systems	O
and	O
applications	O
have	O
chosen	O
to	O
use	O
RocksDB	B-Language
as	O
their	O
embedded	O
storage	O
engine	O
:	O
</s>
<s>
The	O
Ceph	B-Operating_System
's	I-Operating_System
BlueStore	O
storage	O
layer	O
uses	O
RocksDB	B-Language
for	O
metadata	O
management	O
in	O
OSD	O
devices	O
.	O
</s>
<s>
Apache	O
Flink	O
uses	O
RocksDB	B-Language
to	O
store	O
checkpoints	O
.	O
</s>
<s>
FusionDB	O
uses	O
RocksDB	B-Language
as	O
its	O
storage	O
engine	O
for	O
XML	O
,	O
Key/Value	O
,	O
and	O
JSON	O
.	O
</s>
<s>
LogDevice	O
's	O
LogsDB	O
is	O
built	O
atop	O
RocksDB	B-Language
.	O
</s>
<s>
The	O
Manhattan	O
Distributed	O
Key-Value	B-Data_Structure
Store	I-Data_Structure
has	O
used	O
RocksDB	B-Language
as	O
its	O
primary	O
engine	O
to	O
store	O
Twitter	B-Application
data	O
since	O
2018	O
.	O
</s>
<s>
The	O
service	O
that	O
is	O
used	O
for	O
operational	O
data	O
analytics	O
uses	O
RocksDB	B-Language
as	O
its	O
storage	O
engine	O
.	O
</s>
<s>
The	O
ssdb-rocks	O
project	O
uses	O
RocksDB	B-Language
as	O
the	O
storage	O
engine	O
for	O
the	O
SSDB	O
NoSQL	B-General_Concept
Database	O
.	O
</s>
<s>
The	O
TiDB	O
project	O
uses	O
RocksDB	B-Language
as	O
its	O
storage	O
engine	O
.	O
</s>
<s>
Third-party	O
programming	O
language	B-Application
bindings	I-Application
available	O
for	O
RocksDB	B-Language
include	O
:	O
</s>
