<s>
LevelDB	B-Language
is	O
an	O
open-source	B-Application
on-disk	O
key-value	O
store	O
written	O
by	O
Google	B-Application
fellows	O
Jeffrey	O
Dean	O
and	O
Sanjay	O
Ghemawat	O
.	O
</s>
<s>
Inspired	O
by	O
Bigtable	B-Application
,	O
LevelDB	B-Language
is	O
hosted	O
on	O
GitHub	B-Application
under	O
the	O
New	O
BSD	O
License	O
and	O
has	O
been	O
ported	O
to	O
a	O
variety	O
of	O
Unix-based	O
systems	O
,	O
macOS	B-Application
,	O
Windows	B-Application
,	O
and	O
Android	B-Application
.	O
</s>
<s>
LevelDB	B-Language
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
by	O
key	O
.	O
</s>
<s>
It	O
supports	O
batching	O
writes	O
,	O
forward	O
and	O
backward	O
iteration	O
,	O
and	O
compression	O
of	O
the	O
data	O
via	O
Google	B-Application
's	I-Application
Snappy	B-Language
compression	O
library	O
.	O
</s>
<s>
LevelDB	B-Language
is	O
not	O
an	O
SQL	B-Language
database	I-Language
.	O
</s>
<s>
Like	O
other	O
NoSQL	B-General_Concept
and	O
dbm	B-General_Concept
stores	O
,	O
it	O
does	O
not	O
have	O
a	O
relational	B-Architecture
data	I-Architecture
model	I-Architecture
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
support	O
for	O
indexes	B-Data_Structure
.	O
</s>
<s>
Applications	O
use	O
LevelDB	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>
MariaDB	B-Application
10.0	O
comes	O
with	O
a	O
storage	O
engine	O
which	O
allows	O
users	O
to	O
query	O
LevelDB	B-Language
tables	O
from	O
MariaDB	B-Application
.	O
</s>
<s>
LevelDB	B-Language
is	O
based	O
on	O
concepts	O
from	O
Google	B-Application
's	I-Application
Bigtable	B-Application
database	O
system	O
.	O
</s>
<s>
The	O
table	O
implementation	O
for	O
the	O
Bigtable	B-Application
system	O
was	O
developed	O
starting	O
in	O
about	O
2004	O
,	O
and	O
is	O
based	O
on	O
a	O
different	O
Google	B-Application
internal	O
code	O
base	O
than	O
the	O
LevelDB	B-Language
code	O
.	O
</s>
<s>
That	O
code	O
base	O
relies	O
on	O
a	O
number	O
of	O
Google	B-Application
code	O
libraries	O
that	O
are	O
not	O
themselves	O
open	O
sourced	O
,	O
so	O
directly	O
open	O
sourcing	O
that	O
code	O
would	O
have	O
been	O
difficult	O
.	O
</s>
<s>
Jeff	O
Dean	O
and	O
Sanjay	O
Ghemawat	O
wanted	O
to	O
create	O
a	O
system	O
resembling	O
the	O
Bigtable	B-Application
tablet	O
stack	O
that	O
had	O
minimal	O
dependencies	O
and	O
would	O
be	O
suitable	O
for	O
open	O
sourcing	O
,	O
and	O
also	O
would	O
be	O
suitable	O
for	O
use	O
in	O
Chrome	B-Application
for	O
the	O
IndexedDB	O
implementation	O
.	O
</s>
<s>
They	O
wrote	O
LevelDB	B-Language
starting	O
in	O
early	O
2011	O
,	O
with	O
the	O
same	O
general	O
design	O
as	O
the	O
Bigtable	B-Application
tablet	O
stack	O
,	O
but	O
not	O
sharing	O
any	O
of	O
the	O
code	O
.	O
</s>
<s>
LevelDB	B-Language
is	O
used	O
as	O
the	O
backend	O
database	O
for	O
Google	B-Application
Chrome	I-Application
's	O
IndexedDB	O
and	O
is	O
one	O
of	O
the	O
supported	O
backends	O
for	O
Riak	B-General_Concept
.	O
</s>
<s>
Additionally	O
,	O
Bitcoin	B-Language
Core	I-Language
and	O
go-ethereum	O
store	O
the	O
blockchain	B-Application
metadata	O
using	O
a	O
LevelDB	B-Language
database	O
.	O
</s>
<s>
Minecraft	B-Application
Bedrock	O
Edition	O
uses	O
a	O
modified	O
version	O
for	O
chunk	O
and	O
entity	O
data	O
storage	O
.	O
</s>
<s>
Autodesk	O
AutoCAD	O
2016	O
also	O
uses	O
LevelDB	B-Language
.	O
</s>
<s>
Google	B-Application
has	O
provided	O
benchmarks	O
comparing	O
LevelDB	B-Language
's	O
performance	O
to	O
SQLite	B-Language
and	O
Kyoto	B-Language
Cabinet	I-Language
in	O
different	O
scenarios	O
.	O
</s>
<s>
LevelDB	B-Language
outperforms	O
both	O
SQLite	B-Language
and	O
Kyoto	B-Language
Cabinet	I-Language
in	O
write	O
operations	O
and	O
sequential-order	O
read	O
operations	O
.	O
</s>
<s>
LevelDB	B-Language
also	O
excels	O
at	O
batch	O
writes	O
,	O
but	O
is	O
slower	O
than	O
SQLite	B-Language
when	O
dealing	O
with	O
large	O
values	O
.	O
</s>
<s>
The	O
currently	O
published	O
benchmarks	O
were	O
updated	O
after	O
SQLite	B-Language
configuration	O
mistakes	O
were	O
noted	O
in	O
an	O
earlier	O
version	O
of	O
the	O
results	O
.	O
</s>
<s>
Updated	O
benchmarks	O
show	O
that	O
LevelDB	B-Language
also	O
outperforms	O
Berkeley	B-Language
DB	I-Language
,	O
but	O
these	O
tests	O
also	O
show	O
that	O
OpenLDAP	B-Language
LightningDB	B-Language
is	O
much	O
faster	O
(	O
~	O
10	O
times	O
in	O
some	O
scenarios	O
)	O
in	O
read	O
operations	O
and	O
some	O
write	O
types	O
(	O
e.g.	O
</s>
<s>
All	O
the	O
above	O
benchmarks	O
date	O
back	O
from	O
2011	O
to	O
2014	O
,	O
and	O
may	O
only	O
be	O
of	O
historical	O
significance	O
as	O
SQLite	B-Language
,	O
for	O
instance	O
,	O
became	O
significantly	O
more	O
efficient	O
.	O
</s>
<s>
LevelDB	B-Language
has	O
history	O
of	O
database	O
corruption	O
bugs	O
.	O
</s>
