“Redis ismore than justa key-value store,it’s a lifestyle.

–– Mathias Meyer

a data structure server

hash tables

sets

sorted sets

Fundamental data structuresfor a fundamental API

lists

user1234567890field0: abc…field1: def…field2: ghi…field3: jkl…field4: mno…field5: pqr…field6: stu…field7: vwx…field8: yzä…field9: öüß…

hash tables

user1234567890field0: abc…field1: def…field2: ghi…field3: jkl…field4: mno…field5: pqr…field6: stu…field7: vwx…field8: yzä…field9: öüß…

insertread

updatedelete

HMSETHMGETHMSET

DEL

CRUD

RedisClient.java

a data structure server

hash tables

sets

sorted sets

Fundamental data structuresfor a fundamental API

lists

factory settings hand-tuned

hash-max-zipmap-value 2048

2.54MB 1.62MB

0.5M initial size

The Harry Potter Approach

WWVDWhat Would Voldemort Do

101 @Override102 public int scan(…) {104 logger.warn(⁞ "Voldemort does not support Scan semantics");105 return OK;106 }

db/voldemort/src/com/yahoo/ycsb/db/VoldemortClient.java

sorted sets

user1 user2 user3 user5 user8

1 2 3 5 8…

user1 user2 user3 user5 user8

not that easy

user1 user2 user3 user5 user8

not that easy

record name can be anythingthus: position = hash(name)

sorted sets

50% performance hit

workload A

thro

ugh

pu

t

target

workload E

thro

ugh

pu

t

target

workload F

thro

ugh

pu

t

target

“I think the… problem is… believing thatthere can be“one true datastore”.Different technologies excel at different things.

–– Weixi Yen

“I think the… problem is… believing thatthere can be“one true datastore”.Different technologies excel at different things.

–– Weixi Yen

Memory storage is #1

Redis key space

http://spotfireblog.tibco.com/wp-content/uploads/in-memory-analytics.jpg

bandwidth contentionnetworkmemory

200 ops/secsingle-threaded

user1234567890field0: abc…field1: def…field2: ghi…field3: jkl…field4: mno…field5: pqr…field6: stu…field7: vwx…field8: yzä…field9: öüß…

= 1 KB

user1234567890field0: abc…field1: def…field2: ghi…field3: jkl…field4: mno…field5: pqr…field6: stu…field7: vwx…field8: yzä…field9: öüß…

= 1 KBfactory page size := 32 bytes

user1234567890field0: abc…field1: def…field2: ghi…field3: jkl…field4: mno…field5: pqr…field6: stu…field7: vwx…field8: yzä…field9: öüß…

= 1 KBfactory page size := 32 bytes

values must be swapped in their entirety,even for complex types

user1234567890field0: abc…field1: def…field2: ghi…field3: jkl…field4: mno…field5: pqr…field6: stu…field7: vwx…field8: yzä…field9: öüß…

= 1 KBfactory page size := 32 bytes

values must be swapped in their entirety,even for complex types

= 32 pages

user1234567890field0: abc…field1: def…field2: ghi…field3: jkl…field4: mno…field5: pqr…field6: stu…field7: vwx…field8: yzä…field9: öüß…

= 1 KBfactory page size := 32 bytes

values must be swapped in their entirety,even for complex types

= 32 pages vm-page-size et al

user1234567890field0: abc…field1: def…field2: ghi…field3: jkl…field4: mno…field5: pqr…field6: stu…field7: vwx…field8: yzä…field9: öüß…

= 1 KB

= 32 pages

50% performance hit

32-bit 64-bit

4 GB 8 TB

large pointers

redis-cli INFO

Memory storage is #1

meh, persistence

http://www.flickr.com/photos/generationbass/4827013488/

memory overhead

Memory storage is #1

meh, persistence

http://www.flickr.com/photos/generationbass/4827013488/

memory overhead

load phase fails randomly

http://www.flickr.com/photos/31748439@N06/3026024436/

there are no silver bullets