This document provides a summary of new features and improvements in recent versions of Apache HBase, a distributed, scalable, big data store. It discusses major changes and enhancements in HBase 0.92+, 0.94+, and 0.96+, including new HFile formats, coprocessors, caching improvements, performance tuning, and more. The document is intended to bring readers up to date on the current state and capabilities of HBase.

1. 1
HBase
0.96+
A
Report
on
the
Current
Status
Lars
George
|
EMEA
Chief
Architect

2. About
Me
• EMEA
Chief
Architect
@
Cloudera
• ConsulDng
on
Hadoop
projects
(everywhere)
• Apache
CommiLer
• HBase
and
Whirr
• O’Reilly
Author
• HBase
–
The
DefiniDve
Guide
• Now
in
Japanese!
• Contact
• lars@cloudera.com
• @larsgeorge
日本語版も出ました!

3. The
Content...
• Version
History
• Overview
of
new
Features
• Summary

4. CONFIDENTIAL
-­‐
RESTRICTED
Version
History
A
Timeline
Overview

5. HBase
Releases
5
URL:
hLp://s.apache.org/hbase-­‐releases

6. HBase
Releases
–
Issues
Closed
(JIRA)
6
URL:
hLp://s.apache.org/hbase-­‐releases

7. HBase
Releases
–
Issues
Closed
(DisDnct)
7
URL:
hLp://s.apache.org/hbase-­‐releases

8. HBase
Book?
I
targeted
0.92.0
but…
r1130336 | stack | 2011-06-02 00:52:45 +0200 ⤦
(Thu, 02 Jun 2011) | 1 line
Add link to meet up
...
r1234894 | stack | 2012-01-23 17:50:43 +0100 ⤦
(Mon, 23 Jan 2012) | 1 line
Move version on past 0.92.0 to 0.92.1-SNAPSHOT
$ svn log -r 1130336:1234894 | grep "^r" | wc -l
807
8

9. HBase
Book?
I
am
trailing
0.92.0
by
800+
commits,
including
for
example
r1153634 | tedyu | 2011-08-03 21:59:48 +0200 ⤦
(Wed, 03 Aug 2011) | 2 lines
HBASE-3857 Change the HFile Format (Mikhail & Liyin)
…which
is
not
“unimportant”.
J
I
am
working
on
an
update!
9

10. 10
Coprocessors
and
more…
HBase
0.92

11. HBase
0.92
-­‐
Highlights
• 682
issues
addressed
• 811
issues
total
in
0.92.x
line
• New
logo!
(HBASE-­‐4312)
• HFile
v2
(HBASE-­‐3857)
• Distributed
Log
Splilng
(HBASE-­‐1364)
• Enhanced
Master
UI
• Major
compacDon
progress
(HBASE-­‐3900)
• Regions
in
transiDon
(HBASE-­‐4291)
• Tasks
(HBASE-­‐3839)
• Slow
Query
Metrics
(HBASE-­‐4117)
11

12. HBase
0.92
-­‐
Highlights
• Coprocessors
(HBASE-­‐2000)
• Oneap
cache
(HBASE-­‐4027)
• Online
Table
Schema
Change
(HBASE-­‐1730)
• Regions
Size
from
256MB
to
1GB
(HBASE-­‐4374)
• Hadoop
1
Support
(HBASE-­‐5125)
• Snappy
Support
(HBASE-­‐3691)
• Keep
last
version
with
TTL
(HBASE-­‐4071)
• MulDthreaded
CompacDons
(HBASE-­‐4572)
12

13. HFile
v1
–
HBase
0.90
13
• Previously
the
file
layout
was
data
blocks,
meta
blocks
and
then
file
metadata
like
indexes.
• Each
data
block
held
a
magic
header
and
then
the
actual
data
sequenDally.

14. HFile
v2
–
HBase
0.92+
The
2nd
version
of
HFile
splits
the
indexes
and
Bloom
filters
up
into
a
hierarchy
and
interleaves
those
with
data
blocks.
14
The
data
block
header
now
holds
addiDonal
info
on
the
block
itself.
Source:
hLp://blog.cloudera.com/blog/2012/06/hbase-­‐io-­‐hfile-­‐input-­‐output/

15. Coprocessors:
Observers
15

16. Coprocessors:
RPC
Calls
16

17. Slab
Cache
–
Off-­‐heap
Block
Cache
17 hLp://blog.cloudera.com/blog/2012/01/caching-­‐in-­‐hbase-­‐slabcache/
• The
off-­‐heap
cache
uses
Java
NIO’s
Direct
ByteBuffer
structures
• Uses
its
on
slab
allocaDon
handling
• Does
copy-­‐on-­‐read
during
access
of
data
• Uses
L2
cache
and
replaces
OS
buffer
cache

18. 18
Performance
Tuning…
HBase
0.94

19. HBase
0.94
-­‐
Highlights
• 420
issues
addressed
• 1394
issues
total
in
0.94.x
line
• Read
Caching
Improvements
(HBASE-­‐5074)
• Seek
OpDmizaDon
• Bloom
Filter
for
Delete
Family
(HBASE-­‐4532)
• Lazy
Seeks
(HBASE-­‐4465)
• Write
to
WAL
OpDmizaDons
• WAL
Compression
(HBASE-­‐4608)
• Data
Block
Encoding
of
KeyValues
(HBASE-­‐4218)
• Improved
HBaseFsck
(HBASE-­‐5128)
19

20. HBase
0.94
-­‐
Highlights
• Simplified
Region
Sizing
(HBASE-­‐4365)
• Smarter
TransacDon
SemanDcs
• Atomic
Put&Delete
in
One
Call
(HBASE-­‐3584)
• Snapshots
(0.94.6)
(HBASE-­‐7360)
• Atomic
Appends
(HBASE-­‐4102)
• MulD
Increment
and
Append
(HBASE-­‐2947)
• More
Aggressive
Off-­‐Peak
CompacDons
(HBASE-­‐4463)
20

21. HBase
0.94
-­‐
Highlights
• Per
Column
Family
Metrics
(HBASE-­‐4219)
• MulD-­‐row
local
transacDons
(HBASE-­‐5229)
• Pluggable
Split
Key
Policy
(HBASE-­‐5304)
• Load
balance
regions
by
table
(HBASE-­‐3373)
• Also
backported
to
0.92.1
• Make
CompacDon
Code
Pluggable
(HBASE-­‐6427)
• Deprecate
HTablePool
(0.94.11)
(HBASE-­‐6580)
• Canary
Test
Tool
(HBASE-­‐4393)
21

22. Block
Encoding
• Allows
to
reduce
data
footprint
in
memory
• Only
encodes
the
key
porDon
of
a
key/value
pair
• Encoded
keys
stay
encoded
also
during
flushes
• Compression
on
top
of
encoding
takes
care
of
the
values
and
remainder
of
key
data
Example:
• Key
length:
90B
• Value
length:
8B
22
Type
Ra0o
Key
Compression
92%
Total
Compression
85%
LZO
on
same
data
85%
LZO
axer
encoding
91%
hLps://issues.apache.org/jira/browse/HBASE-­‐4218

23. Block
Encoding:
None
23
Source:
hLp://blog.cloudera.com/blog/2012/06/hbase-­‐io-­‐hfile-­‐input-­‐output/
• With
no
encoding
the
Key/Value
structures
are
stored
verbaDm
(with
some
overhead
for
lengths)
• In
the
past
you
were
advised
to
keep
the
“keys”
short
for
that
reason

24. Block
Encoding:
Prefix
Encoding
24
Source:
hLp://blog.cloudera.com/blog/2012/06/hbase-­‐io-­‐hfile-­‐input-­‐output/
• The
encoding
patch
added
a
new
Cell
abstracDon
that
allows
for
extra
fields
in
a
Key/Value
• The
fields
are
used
to
track
necessary
details
for
the
encoding

25. Block
Encoding:
Diff
Encoding
25
Source:
hLp://blog.cloudera.com/blog/2012/06/hbase-­‐io-­‐hfile-­‐input-­‐output/
• Apart
from
the
prefix
encoding
there
are
other
ways
of
encoding
the
keys
• The
diff
encoding
is
one
of
such
approaches

26. Block
Encoding
• Advantage
of
block
encoding
is
faster
decompression/
decoding
• 20-­‐80%
faster
than
LZO
• Also
it
allows
to
seek
data
sDll,
which
is
not
possible
with
compressed
data
• Penalty
is
a
slightly
slower
read
performance
compared
to
non-­‐encoded
keys
• Important
is
to
watch
the
sizes
and
repeDDon
of
key
data,
encoding
might
not
be
useful
for
random
data
26 hLps://issues.apache.org/jira/browse/HBASE-­‐4218

27. 27
The
Singularity
HBase
0.96

28. HBase
0.96
-­‐
Highlights
• 1219
issues
addressed
• 2243
issues
total
in
0.96.x
line
• Improved
Stability
(HBASE-­‐6241/6201)
• ZK
based
Read/Write
locks
for
table
operaDons
(HBASE-­‐7305)
• Scalability
Improvements
(HBASE-­‐8877)
• Schema
Storage
(HBASE-­‐8778)
• Log
Cleaner
for
ReplicaDon
Speed
Up
(HBASE-­‐9208)
• Mean-­‐Time-­‐To-­‐Recovery
(MTTR)
Improvements
(HBASE-­‐5844/5926)
• Distributed
Log
Replay
(HBASE-­‐7006)
• Dedicated
WAL
for
System
Table
(HBASE-­‐7213/8631)
28

29. HBase
0.96
-­‐
Highlights
• Operability
Improvements
• Hooks
for
Health
Scripts
(HBASE-­‐7399/7406)
• Trace
Lagging
Calls
with
HTrace
(HBASE-­‐9121)
• Versioned
RPCs
and
Metadata
(Protobufs)
(HBASE-­‐3505)
• Parallel
Seeks
in
Stores
(HBASE-­‐7495)
• Hadoop
1
and
2
Support
• Secure
Short
Circuit
Reads
on
H2
(HBASE-­‐6783)
• Namespaces
Support
(HBASE-­‐8015)
• New
Metrics
v2
(HBASE-­‐4050)
• Cell
Interface
vs
KeyValue
(HBASE-­‐7162)
29

30. HBase
0.96
-­‐
Highlights
• No
more
ROOT
table
(HBASE-­‐3171)
• Remove
HFile
v1
(HBASE-­‐7660)
• Trie
Data
Block
Encoding
(HBASE-­‐4676)
• Remove
Client-­‐side
Row
Locks
(HBASE-­‐7263/7315)
• CompacDon
and
Flush
Improvements
(HBASE-­‐7516/7763/6466/7678)
(HBASE-­‐7667/7110/7603/7519/7842)
• Improved
Default
ConfiguraDon
(HBASE-­‐4657?)
• Client-­‐side
Type
Library
(HBASE-­‐8089)
30

31. HBase
0.96
-­‐
Highlights
• Online
Region
Merging
(HBASE-­‐7403/8219)
• Bucket
Cache
Support
(HBASE-­‐7404)
• Remove
older
ICV
Calls
(HBASE-­‐7032)
• New
“Bootstrap”
based
UIs!
(HBASE-­‐6135)
• Remove
Client-­‐side
Row
Locks
(HBASE-­‐7263/7315)
• CompacDon
and
Flush
Improvements
(HBASE-­‐7516/7763/6466/7678)
(HBASE-­‐7667/7110/7603/7519/7842)
31

32. 32
—
Michael
Stack,
HBase
PMC
Chair

33. Mean-­‐Time-­‐To-­‐Recovery
(MTTR)
• Lot‘s
of
effort
put
into
improve
how
long
data
might
not
be
accessible
during
a
region
move
• The
offline
period
is
made
up
of
phases:
• a
detecDon
phase,
• a
repair
phase,
• reassignment,
and
finally,
• clients
noDcing
the
data
available
in
its
new
locaDon
• Improvements
in
many
of
those
areas
• Faster
detecDon,
efficient
repair,
parallel
replay
• Dedicated
WAL
for
system
tables
33 hLps://blog.cloudera.com/blog/2013/10/hbase-­‐0-­‐96-­‐0-­‐released/

34. 34
Cell
Level
Security
HBase
0.98

35. HBase
0.98
-­‐
Highlights
• 1303
issues
addressed
• 1458
issues
total
in
0.98.x
line
• Cell
Level
Security
(HBASE-­‐6222/7663/7662)
• Server-­‐side
EncrypDon
(HBASE-­‐7544)
• WAL
Throughput
Improvements
(HBASE-­‐8755)
• Reverse
Scanner
(HBASE-­‐4811)
• MapReduce
over
Snapshot
Files
(HBASE-­‐8369)
• Striped
CompacDons
(HBASE-­‐7667)
• ThroLle
ReplicaDon
(HBASE-­‐9501)
35

36. Cell
Level
Security
• Added
HFile
v3
which
can
store
arbitrary
metadata
in
a
cell,
called
tags
• Also
extended
ACL
checks
to
apply
to
cell
levels
• With
this
visibility
labels
can
be
stored
in
tags
• An
API
and
CLI
tools
are
provided
that
are
akin
to
Accumulo’s,
axer
which
it
is
modeled
• AddiDonal
encrypDon
of
data
at
rest
ensures
further
security
of
sensiDve
data
36 hLps://blogs.apache.org/hbase/entry/hbase_cell_security

37. Visibility
Labels
The
API
allows
to
set
visibility
by
using
expressions
with
“&”,
“|”,
and
“!”,
as
well
as
“(“
and
“)”,
e.g.
label
set
of
{
confidenDal,
secret,
topsecret,
probaDonary
}
could
be
combined
as
( secret | topsecret ) & !probationary
At
runDme
the
expressions
are
evaluated
against
a
user
and
then
applied
to
each
cell.
37

38. 38
The
Future…
HBase
0.??

39. HBase
Future
• Not
much
is
wriDng
in
stone
yet
• Master
gets
rewriLen
and
also
META
table
handling
• Build
in
consensus
(HBASE-­‐10296)
• Co-­‐locate
Master
and
META
(HBASE-­‐10569)
• MTTR
is
further
extended
into
interesDng
areas
• Read
replicas
(HBASE-­‐10070)
It
has
to
be
seen
when
1.0.0
is
released
and
what
it
contains.
Your
opinion
counts!
39

40. 40
Ques0ons?
@larsgeorge