<s>
Tarantool	B-Operating_System
is	O
an	O
in-memory	B-General_Concept
computing	B-Device
platform	I-Device
with	O
a	O
flexible	O
data	O
schema	O
,	O
best	O
used	O
for	O
creating	O
high-performance	O
applications	O
.	O
</s>
<s>
Two	O
main	O
parts	O
of	O
it	O
are	O
an	O
in-memory	B-General_Concept
database	I-General_Concept
and	O
a	O
Lua	B-Language
application	B-Application
server	I-Application
.	O
</s>
<s>
Tarantool	B-Operating_System
maintains	O
data	O
in	O
memory	O
and	O
ensures	O
crash	O
resistance	O
with	O
write-ahead	B-Algorithm
logging	I-Algorithm
and	O
snapshotting	B-Application
.	O
</s>
<s>
It	O
includes	O
a	O
Lua	B-Language
interpreter	O
and	O
interactive	O
console	O
,	O
but	O
also	O
accepts	O
connections	O
from	O
programs	O
in	O
several	O
other	O
languages	O
.	O
</s>
<s>
In	O
2010	O
for	O
a	O
project	O
head	O
it	O
hired	O
a	O
former	O
technical	O
lead	O
from	O
MySQL	B-Application
.	O
</s>
<s>
Open-source	O
contributors	O
have	O
been	O
active	O
especially	O
in	O
the	O
area	O
of	O
external-language	O
connectors	O
for	O
C	B-Language
,	O
Perl	B-Language
,	O
PHP	B-Application
,	O
Python	B-Language
,	O
Ruby	B-Language
,	O
and	O
node.js	B-Language
.	O
</s>
<s>
Tarantool	B-Operating_System
became	O
part	O
of	O
the	O
Mail.Ru	O
backbone	O
,	O
used	O
for	O
dynamic	O
content	O
such	O
as	O
user	O
sessions	O
,	O
unsent	O
instant	O
messages	O
,	O
task	O
queues	O
,	O
and	O
a	O
caching	O
layer	O
for	O
traditional	O
relational	O
databases	O
such	O
as	O
MySQL	B-Application
or	O
PostgreSQL	O
.	O
</s>
<s>
By	O
2014	O
Tarantool	B-Operating_System
had	O
also	O
been	O
adopted	O
by	O
the	O
social	O
network	O
services	O
Badoo	O
and	O
Odnoklassniki	O
(	O
the	O
latter	O
is	O
affiliated	O
with	O
Mail.Ru	O
since	O
2010	O
)	O
.	O
</s>
<s>
All	O
data	O
is	O
maintained	O
in	O
memory	O
(	O
RAM	O
)	O
,	O
with	O
data	O
persistence	O
ensured	O
by	O
write-ahead	B-Algorithm
logging	I-Algorithm
and	O
snapshotting	B-Application
,	O
and	O
for	O
those	O
reasons	O
some	O
industry	O
observers	O
have	O
compared	O
Tarantool	B-Operating_System
to	O
Membase	B-Operating_System
.	O
</s>
<s>
Replication	O
is	O
asynchronous	O
and	O
failover	O
(	O
getting	O
one	O
Tarantool	B-Operating_System
server	O
to	O
take	O
over	O
from	O
another	O
)	O
is	O
possible	O
either	O
from	O
a	O
replica	O
server	O
or	O
from	O
a	O
"	O
hot	O
standby	O
"	O
server	O
.	O
</s>
<s>
Tarantool	B-Operating_System
uses	O
Lua-style	O
coroutines	O
and	O
asynchronous	B-Architecture
I/O	I-Architecture
.	O
</s>
<s>
The	O
result	O
is	O
that	O
application	O
programs	O
or	O
stored	O
procedures	O
must	O
be	O
written	O
with	O
cooperative	B-Operating_System
multitasking	I-Operating_System
in	O
mind	O
,	O
rather	O
than	O
the	O
more	O
popular	O
preemptive	O
multitasking	O
.	O
</s>
<s>
Supported	O
index	O
types	O
are	O
B-tree	B-Architecture
,	O
hash	O
,	O
bitmap	O
,	O
and	O
R-tree	B-Library
(	O
spatial	O
)	O
.	O
</s>
<s>
In	O
2017	O
Tarantool	B-Operating_System
introduced	O
an	O
optional	O
on-disk	O
storage	B-General_Concept
engine	I-General_Concept
which	O
allows	O
databases	O
larger	O
than	O
memory	O
size	O
.	O
</s>
<s>
In	O
2019	O
Tarantool	B-Operating_System
introduced	O
an	O
optional	O
SQL	B-Language
interface	O
which	O
complies	O
with	O
most	O
of	O
the	O
mandatory	O
features	O
of	O
the	O
official	O
SQL	B-Language
standard	O
.	O
</s>
<s>
Tarantool	B-Operating_System
comes	O
as	O
part	O
of	O
the	O
official	O
distributions	O
for	O
some	O
Linux	B-Application
distros	O
such	O
as	O
Debian	O
,	O
Fedora	O
or	O
Ubuntu	B-Operating_System
.	O
</s>
<s>
The	O
Tarantool	B-Operating_System
organization	O
also	O
supplies	O
downloads	O
for	O
other	O
Linux	B-Application
distributions	O
,	O
OS	O
X	O
,	O
and	O
FreeBSD	B-Operating_System
.	O
</s>
<s>
Tarantool	B-Operating_System
can	O
be	O
extended	O
with	O
modules	O
installed	O
using	O
LuaRocks	B-Language
,	O
and	O
it	O
includes	O
its	O
own	O
selection	O
of	O
extension	O
rocks	O
.	O
</s>
