Based on a paper with the same name

1. SHARE Interface in Flash Storage
for Relational and NoSQL Databases
Farzad Nozarian
Information Systems Group - Saarland University
infosys.cs.uni-saarland.de

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Motivation

3. Motivation
3
Page Write Atomicity

4. Guarantee write atomicity in databases
4
Copy-on-write[ ]Journaling[ ]
Write amplifications

5. Redundant Writes in MySQL/InnoDB
5
DRAM Buffer
Dirty Page Write
Clean Dirty
In-Place Update
Journaling
for Atomic Page Write
Double Write in MySQL/InnoDB
D’ C’ B A’
Database
A’
C’
D
B Double Write Buffer
(DWB)
A’ C’

6. Copy-on-Write in Couchbase
6
A
B C
D1 D2 D3
Valid
Stale
Tree Nodes
Documents
A’
C’
D2’
new copy
C
A
old document
D2
Costly compaction
operation
Wandering-tree
write amplification

7. Problem of atomic
writes In flash storages
7

8. Seems similar…
8
Copy-on-write
In flash
Out-of-place write
in database
Explicitly change the address mapping inside flash storage
SHARE

9. SHARE Architecture
9
SHARE Interface
LPN
PPN
Flash Storage
Page Mapping Table
(L2P)
Physical Address in
Flash Memory (PPN)
D2’
A
B C
D1 D2 D3
Valid
StaleTree Nodes
Documents Write amplificationD2
D2D2 D2’

10. 10
void SHARE(double LPN1, double LPN2)
}
add_as_SATA_command() ;
if(is_available_SATA == false)
use_ioctl() ;
bool is_batch_supported = true ;
{

11. Extending MySQL/InnoDB
11
H
A
R
E
Writing another copy in the DWB
Writing each page to its original location
Call SHARE command with the LPN pair(s)
Evicting dirty pages from the buffer

12. Couchbase Compaction With SHARE
12
Valid
Stale
LPN
PPN
D1 D2 D3 D1’
Flash Storage
Page Mapping Table
(L2P)
Physical Address in
Flash Memory (PPN)
E
F G
D1’ D2 D3
Compaction
File 2
SHARE(File2’s LPNs, File1’s LPNs)
A
B C
D1 D2 D3
Tree Nodes
Documents
D1’
B’
A’
File 1

13. 13
Easy to incorporate into the existing
storage interface frameworks

14. Using SHARE with marginal code changes
14
500
line
new
codes
200
line
new
codes

15. Complicating
garbage collection process
Multiple reverse mapping for each physical page
15

16. No SSD memory space for extra data structures
1GB NAND
~1MB DRAM
Forward mapping
Cache
I/O buffers
16

17. LinkBench YCSB
Configurable benchmark for social graphs
Benchmark framework for cloud systems
Workloads
17
Workload-A: 50% read, 50% update
Workload-F: 100% read-modify-write
3 databases with page sizes of 4KB, 8KB,16KBKB

18. The Effect of SHARE on Throughput
18
LinkBench throughput on MySQL/InnoDB
241
277
316
578
617
799
0
200
400
600
800
1000
50MB 100MB 150MB
TransactionsPerSecond(TPS)
Buffer Size
DWB-ON SHARE
241
118
60
578
271
131
0
200
400
600
800
1000
4KB 8KB 16KB
TransactionsPerSecond(TPS)
Page Size
DWB-ON SHARE
Figure (a) Figure (b)

19. The Effect of SHARE on IO Activities
19
IO activities inside OpenSSD (50MB buffer cache, 4KB page)
0
50000
100000
150000
200000
250000
300000
350000
400000
50MB 100MB 150MB
WriteCount(page)
Buffer Size
DWB-ON SHARE
0
500
1000
1500
2000
2500
3000
3500
4000
4500
50MB 100MB 150MB
GarbageCollection(GC)Count
Buffer Size
DWB-ON SHARE
0
20000
40000
60000
80000
100000
120000
140000
160000
180000
200000
50MB 100MB 150MB
Copy-backCount(page)
Buffer Size
DWB-ON SHARE
45% 55% 75%
Figure (a) Figure (b) Figure (c)

20. Effect of SHARE on Workload-F
20
0
200
400
600
800
1000
1200
1400
1600
1800
1 4 16 64 256
WrittenBytes(MB)
Batch-Size
DWB-ON SHARE
38.78
218.83
396.08
555.6
641.68
133.89
443.42
889.34
1192.35
1260.93
0
200
400
600
800
1000
1200
1400
1 4 16 64 256
OperationsPerSecond(OPS)
Batch-Size
DWB-ON SHARE
Figure (a)
YCSB throughput on Couchbase: Workload-F
Figure (b)

21. Effect of SHARE on Workload-A and Compaction
21
Effect of SHARE on compaction
Elapsed
Time (sec)
Written Bytes
(MB)
Original 277.52 1126.4
SHARE 88.38 150.6
118.58
455.86
801.15
1033.12
1108.71
264.67
856.35
1564.41
1767.3 1787.21
0
500
1000
1500
2000
1 4 16 64 256
OPERATIONSPERSECOND(OPS)
BATCH-SIZE
DWB-ON SHARE
YCSB throughput on Couchbase
3.1X 7.5X

22. 22
Rewired User-space Memory Access[ ]
RUMA
Rewiring the mappings from virtual to physical memory at runtime

23. Rewiring Memory Layers + Swapping Pages
23
filephysicalvirtual
b ; b+p-1 b+p ; b+2.p-1
0 ; p-1 p ; 2p-1
mmap()
mmap() mmap()
ppage42 ppage7
vpage0 vpage1
ppage42 ppage7
vpage0 vpage1vpage0 vpage1

24. Conclusion and future work
24
FTL
Write atomicity
with Journaling
and Copy-on-write
SHARE allows
applications to
change the FTL
Extending MySQL
and Couchbase
to exploit SHARE
Reducing SSDs
performance
and lifespan
Write atomicity
almost at no cost!
Extending
PostgreSQL and
SQLite, Ext4, …

25. 25
Performing costly operations
minimal
writes
with

26. Just MySQL and Couchbase?
26
…

27. Related Work
27
FTL for journal mode Closest approach to SHARE Tailored to journaling FS
Copy-on-write mechanism Transactional atomicity Update-in-place
JFTLJFTL(2009) X-FTL(2013) RUMA(2016)

28. Complicating
garbage collection process
Multiple reverse mapping for each physical page
Physical to logical
(PPN)
#12
Logical to physical
28

29. The Effect Of SHARE On Tail Tolerance
29
Transaction DWB-On SHARE
I/O
Type
Name Mean P50 Max Mean P50 Max
Read
Get_Node 51.4 12 1363.3 23.9 10 901.1
Count_Link 32.8 5 1244.4 14.4 5 747.4
Multiget_Link 40.7 5 1573.5 15.2 6 313.3
Get_Link_List 39.4 5 17467.4 17.2 5 6140.7
write
Add_Node 6.3 0.4 1521.0 1.5 0.3 554.6
Update_Node 64.0 15 2071.4 28.3 14 823.8
Delete_Node 62.6 13 1104.6 26.3 12 596.7
Add_Link 119.3 40 2248.2 49.7 27 730.4
Delete_Link 70.5 16 1417.6 30.3 14 1132.8
Updae_Link 114.9 38 2270.5 49.4 26 1102.5
Distribution of LinkBench transaction latency (in millisec)

30. Picture References
1. 2. 3. 4. 5. 6. 7. 8. 9. 10.
11. 12. 13. 14. 15. 16. 17. 18. 19. 20.
21. 22. 23. 24. 25. 26. 27. 28. 29. 30.
31. 32. 33. 34. 35. 36. 37. 38. 39. 40.
41. 42. 43. 44. 45. 46. 47. 48. 49. 50.
51. 52. 53. 54. 55. 56.

31. Picture References
[1] Icons made by Chris Veigt from www.flaticon.com is licensed by CC 3.0 BY
[2, 5, 6, 8, 9, 12, 13, 16, 18, 20, 24, 25, 27, 29, 39] Icons made by Freepik from www.flaticon.com is licensed by CC 3.0 BY
[3, 4, 37] Icons made by Gregor Cresnar from www.flaticon.com is licensed by CC 3.0 BY
[7] Icons made by Pixel Buddha from www.flaticon.com is licensed by CC 3.0 BY
[10] Icons made by Lucy G from www.flaticon.com is licensed by CC 3.0 BY
[11, 14, 15, 21, 22, 35] Icons made by Madebyoliver from www.flaticon.com is licensed by CC 3.0 BY
[17, 40] Icons made by Vectors Market from www.flaticon.com is licensed by CC 3.0 BY
[19, 36] Icons made by Dave Gandy from www.flaticon.com is licensed by CC 3.0 BY
[23] Icons made by Nikita Golubev from www.flaticon.com is licensed by CC 3.0 BY
[26] Icons made by Twitter from www.flaticon.com is licensed by CC 3.0 BY
[28] Icons made by DinosoftLabs from www.flaticon.com is licensed by CC 3.0 BY
[30] Icons made by Becris from www.flaticon.com is licensed by CC 3.0 BY
[31] https://upload.wikimedia.org/wikipedia/en/thumb/6/62/MySQL.svg/1200px-MySQL.svg.png
[32] https://safenet.gemalto.com/uploadedImages/images/Logos/postgresql-logo.png
[33] https://upload.wikimedia.org/wikipedia/commons/thumb/3/38/SQLite370.svg/2000px-SQLite370.svg.png
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32. Picture References
[34] https://upload.wikimedia.org/wikipedia/commons/6/67/Couchbase%2C_Inc._official_logo.png
[38] http://www.pinsdaddy.com/
[41] https://g16languagebslmackay.files.wordpress.com/2014/04/landfill-ban-on-unsorted-waste-could-save-c2a32-1-billion.jpg
[42] https://c.slashgear.com/wp-content/uploads/2012/10/google-datacenter-tech-21.jpg
[43] http://assets.inoutput.io/images/code-minimalism-what-is-it-and-should-you-use-it/Code-minimalism-article_-FINAL-RESIZE.jpg
[44] https://willnationsdev.files.wordpress.com/2017/03/orange-halves-02.jpg?w=613&h=460
[45] https://images-na.ssl-images-amazon.com/images/I/71hV7hZcRmL._SL1500_.jpg
[46] https://www.etb-tech.com/media/catalog/product/cache/1/image/1200x800/8914f37fee28e25f390b3ea202924aa1/e/m/emc_hssdc2-hssdc2_4gb_fibre_cable_038-003-514-closeup.jpg
[47] https://images-na.ssl-images-amazon.com/images/I/71kJ7lTJw-L._SL1010_.jpg
[48] https://images.techhive.com/images/article/2013/05/intel_ssd_525_series_1160-100037016-orig.png
[49] https://images-fe.ssl-images-amazon.com/images/I/71Ae-lqBdCL._SL1500_.jpg
[50] http://www.procomponentes.com/70869-thickbox_default/startechcom-cable-2m-sff-8470-a-sff8088-infiniband-cx4-molex-lanelink-mini-sas-molex-ipass-isas88702.jpg
[51] http://www.sps.cs.uni-saarland.de/resources/uds-logo.svg
[52] https://garciamedialife.files.wordpress.com/2014/12/subway-10.jpg
[53] http://www.bbq4all.it/wp-content/uploads/2017/05/codecode.jpg
[54] http://www.all-electronics.de/wp-content/uploads/2016/10/Bild1-bigstock-Festplatte.jpg
[55] https://www.iguides.ru/upload/medialibrary/e00/e00fbe4066eff1d84b279c039e0e32f6.jpg
[56] http://s1.1zoom.me/b6862/130/Closeup_Electric_wire_Multicolor_512328_3840x2160.jpg
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