redis überall

redis
überall
Mariano Vallés!
@zucaritask

redis
/rədɪs/
in memory key-value cache and store
@zucaritask

redis
/rədɪs/
in memory key-value cache and store
Considered a data structure server since keys
can contain strings, hashes, lists, sets …
@zucaritask

First: Nested hashes
In redis:
[ !
] a hash has values
[ ] those values can be hashes

In redis:
! ✓
[ ] a hash has values

In redis:
✓
[ ] a hash has values
!
✘

:001
>
$redis.hgetall(“levels:1234").
!
{
easy_10:
“{"progress":0,"goal":10,"started_at":1415278026,"finished_at":0}",
easy_20:
"{"progress":0,"goal":20,"started_at":1415278050,"finished_at":0}"
}

:001
>
!
{
easy_10:
easy_20:
}
:002
>
$redis.hgetall(“levels:1234").inject({})
do
|result,
(key,
value)|
result[key]
=
JSON.parse(value);
result
end
=>
{
easy_10:
{progress:
0,
goal:
10,
started_at:
1415278026,
finished_at:
0}
easy_20:
{progress:
0,
:goal:
20,
started_at:
1415278050,
finished_at:
0}
}

Redis hash
:001
>
!
{
easy_10:
easy_20:
}
:002
>$redis.hgetall(“levels:1234").inject({})
do
|result,
(key,
value)|
result[key]
=
JSON.parse(value);
result
end
=>
{
easy_10:
{:progress
=>
0,
:goal
=>
10,
started_at:
1415278026,
finished_at:
0}
easy_20:
{:progress
=>
0,
:goal
=>
20,
started_at:
1415278050,
finished_at:
0}
}

Redis hash
:001
>
!
{
!
easy_10:
easy_20:
}
deal with
le crowd
:002
>$redis.hgetall(“levels:1234").inject({})
do
|result,
(key,
value)|
result[key]
=
JSON.parse(value);
result
end
=>
{
easy_10:
{:progress
=>
0,
:goal
=>
10,
started_at:
1415278026,
finished_at:
0}
easy_20:
{:progress
=>
0,
:goal
=>
20,
started_at:
1415278050,
finished_at:
0}
}

From:
{
easy_10:
“{"progress":0,"goal":10,"started_at":1415278026,"finished_at":easy_20:
"{"progress":0,"goal":20,"started_at":1415278050,"finished_at":}

From:
{
easy_10:
To:

From:
{
easy_10:
To:
{
easy_10:
"0,10,1415278026,0",
easy_20:
"4,20,1415278050,0"
}

{
easy_10:
"0,10,1415278026,0",
easy_20:
"4,20,1415278050,0"
} To:

goal
{
easy_10:
"0,10,1415278026,0",
easy_20:
"4,20,1415278050,0"
} To:
progress
started_at
finished at

In redis:
[ ] hashes are memory efficient
[ ] millions of hashes are memory
efficient
!
Last: Avoiding hashes

In redis:
efficient
! ✓

In redis:
✓
efficient
!
✘

:01
>
$redis.hgetall(“counter:1234”)

:01
>
=>
{
popup_shown:
1,
extra_life_given:
0
}

the crowd
has no mercy
de a l w i th i t

From:
To:
:01
>
=>
{
popup_shown:
1,
extra_life_given:
0
}

From:
To:
:01
>
=>
{
popup_shown:
1,
extra_life_given:
0
}
:01
>
$redis.get(“counter:1234”)
=>
"u0000u0001"

From:
To:
:01
>
=>
{
popup_shown:
1,
extra_life_given:
0
}
:01
>
=>
"u0000u0001"
A sequence of binary data

From:
To:
:01
>
=>
{
popup_shown:
1,
extra_life_given:
0
}
:01
>
=>
"u0000u0001"
A sequence of binary data
Less memory usage FTW!

class
Counter
!
COUNTERS
=
%w[
VERSION
popup_shown
extra_life_given
]
!
def
set(key,
value)
$redis.setrange(
user_id,
COUNTERS.index(key),
[value].pack("C*")
)
end
!
def
[](key)
char
=
$redis.getrange(user_id,
index,
index)
char.unpack("C*").first.to_i
end
end

class
Counter
!
COUNTERS
=
%w[
VERSION
popup_shown
extra_life_given
]
!
def
set(key,
value)
$redis.setrange(
user_id,
[value].pack("C*")
)
end
!
def
set the value for a part of a string
[](key)
char
=
index,
index)
end
end

class
Counter
!
COUNTERS
=
%w[
VERSION
popup_shown
extra_life_given
]
!
def
set(key,
value)
$redis.setrange(
user_id,
[value].pack("C*")
)
end
!
def
starting in this position
[](key)
char
=
index,
index)
end
end

class
Counter
!
COUNTERS
=
%w[
VERSION
popup_shown
extra_life_given
]
!
def
set(key,
value)
$redis.setrange(
user_id,
[value].pack("C*")
)
end
!
def
starting in this position
turn an integer into an 8-bit unsigned char
[](key)
char
=
index,
index)
end
end

:01
>
[0].pack(“C*”)
=>
"x00"

:01
>
[0].pack(“C*”)
=>
"x00"
:02
>
[256].pack(“C*”)
=>
"x00"

Ac h t u n g , 8 bits !
:01
>
[0].pack(“C*”)
=>
"x00"
:02
>
[256].pack(“C*”)
=>
"x00"

redis
überall
but
@zucaritask
use
beware of the crowds

redis überall

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