0.96.0

Bay Area Hadoop User Group, October 16th, 2013

Michael Stack <stack@apache.org>

• 0.96.0 Release Manager• Chair of Apache HBase PMC*• Apache Hadoop PMC• Engineer at Cloudera in San Francisco

* Project Management Committee

HBase?

"...scalable, distributed datastore."

"...open source, distributed, scalable, consistent, low latency, random access non-relational database..."

Inspiration

A Google Technology described in a 2006 paper, by Chang et al.?

●Apache Top-level Project○hbase.apache.org●Up out of Apache Hadoop contrib●Project goal: “Billions of rows X millions of columns on clusters of ‘commodity hardware”●HBase persists all data to HDFS●Uses Apache ZooKeeper○Cluster coordination

When would I use it?

BIG DATA

Random read/writes

SCALING!

Who uses it?

Who runs the project?

Diverse team*

* http://hbase.apache.org/team-list.html

COMMITTERS!

Preferably ALIVE!

•Release every month• Each more stable•& more performant•Some features…• Wire compatible between releases

•Currently at 0.94.12

http://www.flickr.com/photos/sysli/3026288256/sizes/o/in/photostream/

(Self-)Migration

Downstreamers● Minimal API disturbance

–None?–Last-minute feedback

●Hive, Sqoop, OpenTSDB● Deprecations

Stats● >2k issues fixed

– >1500 in 0.96.x only● Currently 6th Release Candidate● Branched 7months ago● 18months in the making

Requirements● Hadoop 1.0.3+● Hadoop 2.1.0-beta+● Must choose one

Big Themes● Stability● Operability

–Insight, tools● Scalability● Evolvability

http://www.flickr.com/photos/allspaw/5815258929/sizes/o/in/photostream/

http://www.flickr.com/photos/allspaw/5815258929/sizes/o/in/photostream/

http://www.flickr.com/photos/38595542@N02/3690830720/sizes/o/in/photostream/

• Dedicated meta WAL

• Don't put WAL replicas on local node– 33% of reads have to timeout

• Lowered ZK timeout– 30s instead of 180s

• Watcher script kills znode– Detection time approaches 0

• Faster assignment

HBase

• HDFS-4721 Speed up lease/block recovery when DN fails and a block goes into recovery– Do not recover on STALE DNs

• HDFS-3703 Decrease the datanode failure detection time– Avoid reading STALE DNs

• HDFS-3912 Detecting and avoiding stale datanodes for writing

HDFS

● Faster WAL replay/Distributed WAL Replay– No intermediate files

● No wait on NN– Committed

● Experimental● Regions online immediately for Writes

– Read older consistent view● “Favored Nodes”

Coming...

One rationale for pb: http://goo.gl/N0HO6n

• System tables• Filesystem• Up in zookeeper• Over the wire

RPC• Implements Protobuf Service

●Specification!• Data on the sideoEncodingoCompression

PB DATA

Scalability• e.g. Replicating 1k to 1k & heading north

• HBASE-8778 Region assigments scan table directory making them slow for huge tables

• HBASE-9208 ReplicationLogCleaner slow at large scale

• HBASE-8877 Reentrant row locks

Snapshots• By TableoSnapshot, clone, restore, export

• InexpensiveoJust metadata

• Good for...oBackupsoReplicationoOffline processing

Integration Tests• Cluster test module

o Standalone or clustero Sizeable

x data x runtime

• "Borrows" test types from all overo Netflix "ChaosMonkey"o Apache Accumulo linked-list dataloss

checkerhbase-it/src/test/java//org/apache/hadoop/hbase/mapreduce/IntegrationTestBulkLoad.java

hbase-it/src/test/java//org/apache/hadoop/hbase/mapreduce/IntegrationTestImportTsv.java

hbase-it/src/test/java//org/apache/hadoop/hbase/mttr/IntegrationTestMTTR.java

hbase-it/src/test/java//org/apache/hadoop/hbase/test/IntegrationTestBigLinkedList.java

hbase-it/src/test/java//org/apache/hadoop/hbase/test/IntegrationTestLoadAndVerify.java

hbase-it/src/test/java//org/apache/hadoop/hbase/trace/IntegrationTestSendTraceRequests.java

StochasticLoadBalancer

• Region Count

• Locality

• Movement Cost

• Table Count

• Regions/Table/RegionServer

• Read/Write Counts

• Memstore Size

• Storefile Size

Tracing• Review HDFS-5274 Add Tracing to HDFS!

Namespaces• Grouping of tables

– Like database in mysql

• System/User– hbase:meta

• Quota• Coming

– Security by ns– Grouping on cluster by ns

Metrics2● Radical revamp● Module of Interfaces

–H1 and H2 Impls modules● Categories/Naming/Patterns

API● Client/Dev● Hadoop Annotations

– Stable/Evolving/Private● Cell Interface

– KeyValue deprecated

Miscellaneous• X-Row (in-region) Transactions• Hardened Assignment• Hardened Replication• New UI• Online Merge• Finer grained ACLs• More Coprocessor hooks

More Misc.• Maven modularized• Client-side Types• Revamped defaults• Compactionso Pluggableo Smarter triggers

• Windows!

0.96.1, 0.96.2, etc.● Bug fixes● Performance fixes● ONLY!● No features!

• Right after 0.96.0– Month or two

• Rolling upgrade from 0.96.0

• In-line Cell-tags• Quota/Groupings• Reverse Scan

1.0.0?

Thank You!stack@apache.org