<s>
Apache	B-General_Concept
Parquet	I-General_Concept
is	O
a	O
free	B-License
and	I-License
open-source	I-License
column-oriented	B-General_Concept
data	O
storage	O
format	O
in	O
the	O
Apache	B-Application
Hadoop	I-Application
ecosystem	O
.	O
</s>
<s>
It	O
is	O
similar	O
to	O
RCFile	O
and	O
ORC	B-General_Concept
,	O
the	O
other	O
columnar-storage	O
file	O
formats	O
in	O
Hadoop	B-Application
,	O
and	O
is	O
compatible	O
with	O
most	O
of	O
the	O
data	O
processing	O
frameworks	O
around	O
Hadoop	B-Application
.	O
</s>
<s>
It	O
provides	O
efficient	O
data	B-General_Concept
compression	I-General_Concept
and	O
encoding	B-Algorithm
schemes	O
with	O
enhanced	O
performance	O
to	O
handle	O
complex	O
data	O
in	O
bulk	O
.	O
</s>
<s>
The	O
open-source	B-Application
project	O
to	O
build	O
Apache	B-General_Concept
Parquet	I-General_Concept
began	O
as	O
a	O
joint	O
effort	O
between	O
Twitter	B-Application
and	O
Cloudera	B-General_Concept
.	O
</s>
<s>
Parquet	O
was	O
designed	O
as	O
an	O
improvement	O
on	O
the	O
Trevni	O
columnar	O
storage	O
format	O
created	O
by	O
Doug	O
Cutting	O
,	O
the	O
creator	O
of	O
Hadoop	B-Application
.	O
</s>
<s>
Since	O
April	O
27	O
,	O
2015	O
,	O
Apache	B-General_Concept
Parquet	I-General_Concept
has	O
been	O
a	O
top-level	O
Apache	O
Software	O
Foundation	O
(	O
ASF	O
)	O
-sponsored	O
project	O
.	O
</s>
<s>
Apache	B-General_Concept
Parquet	I-General_Concept
is	O
implemented	O
using	O
the	O
record-shredding	O
and	O
assembly	O
algorithm	O
,	O
which	O
accommodates	O
the	O
complex	O
data	B-General_Concept
structures	I-General_Concept
that	O
can	O
be	O
used	O
to	O
store	O
data	O
.	O
</s>
<s>
Apache	B-General_Concept
Parquet	I-General_Concept
is	O
implemented	O
using	O
the	O
Apache	B-Protocol
Thrift	I-Protocol
framework	O
,	O
which	O
increases	O
its	O
flexibility	O
;	O
it	O
can	O
work	O
with	O
a	O
number	O
of	O
programming	O
languages	O
like	O
C++	B-Language
,	O
Java	B-Language
,	O
Python	B-Language
,	O
PHP	B-Application
,	O
etc	O
.	O
</s>
<s>
As	O
of	O
August	O
2015	O
,	O
Parquet	O
supports	O
the	O
big-data-processing	O
frameworks	O
including	O
Apache	B-General_Concept
Hive	I-General_Concept
,	O
Apache	B-General_Concept
Drill	I-General_Concept
,	O
Apache	B-Language
Impala	I-Language
,	O
,	O
Apache	B-Language
Pig	I-Language
,	O
Cascading	B-General_Concept
,	O
Presto	B-Language
and	O
Apache	B-Language
Spark	I-Language
.	O
</s>
<s>
It	O
is	O
one	O
of	O
external	O
data	O
formats	O
used	O
by	O
pandas	B-Application
Python	B-Language
data	O
manipulation	O
and	O
analysis	O
library	O
.	O
</s>
<s>
In	O
Parquet	O
,	O
compression	O
is	O
performed	O
column	O
by	O
column	O
,	O
which	O
enables	O
different	O
encoding	B-Algorithm
schemes	O
to	O
be	O
used	O
for	O
text	O
and	O
integer	O
data	O
.	O
</s>
<s>
This	O
strategy	O
also	O
keeps	O
the	O
door	O
open	O
for	O
newer	O
and	O
better	O
encoding	B-Algorithm
schemes	O
to	O
be	O
implemented	O
as	O
they	O
are	O
invented	O
.	O
</s>
<s>
Parquet	O
has	O
an	O
automatic	O
dictionary	B-Algorithm
encoding	I-Algorithm
enabled	O
dynamically	O
for	O
data	O
with	O
a	O
small	O
number	O
of	O
unique	O
values	O
(	O
i.e.	O
</s>
<s>
Parquet	O
implements	O
a	O
hybrid	O
of	O
bit	O
packing	O
and	O
RLE	O
,	O
in	O
which	O
the	O
encoding	B-Algorithm
switches	O
based	O
on	O
which	O
produces	O
the	O
best	O
compression	O
results	O
.	O
</s>
<s>
This	O
strategy	O
works	O
well	O
for	O
certain	O
types	O
of	O
integer	O
data	O
and	O
combines	O
well	O
with	O
dictionary	B-Algorithm
encoding	I-Algorithm
.	O
</s>
<s>
Apache	B-General_Concept
Parquet	I-General_Concept
is	O
comparable	O
to	O
RCFile	O
and	O
Optimized	O
Row	O
Columnar	O
(	O
ORC	B-General_Concept
)	O
file	O
formats	O
all	O
three	O
fall	O
under	O
the	O
category	O
of	O
columnar	O
data	O
storage	O
within	O
the	O
Hadoop	B-Application
ecosystem	O
.	O
</s>
<s>
They	O
all	O
have	O
better	O
compression	O
and	O
encoding	B-Algorithm
with	O
improved	O
read	O
performance	O
at	O
the	O
cost	O
of	O
slower	O
writes	O
.	O
</s>
<s>
In	O
addition	O
to	O
these	O
features	O
,	O
Apache	B-General_Concept
Parquet	I-General_Concept
supports	O
limited	O
schema	B-Application
evolution	I-Application
,	O
i.e.	O
,	O
the	O
schema	O
can	O
be	O
modified	O
according	O
to	O
the	O
changes	O
in	O
the	O
data	O
.	O
</s>
<s>
Apache	B-Application
Arrow	I-Application
is	O
designed	O
as	O
an	O
in-memory	O
complement	O
to	O
on-disk	O
columnar	O
formats	O
like	O
Parquet	O
and	O
ORC	B-General_Concept
.	O
</s>
