Download - JDD2014: Multitenant Search - Pablo Barros

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Mul@tenant Search JDD 2014, Krakow -‐ PL

Pablo Barros Applica@ons Architect October 14, 2014

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•  The opinions and views expressed in this talk are my own, and do not necessarily reflect the opinions or views of my employer.

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About me

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About me

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Giveaway

•  Elas@csearch Server – Second Edi@on – By Rafal Kuc

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Agenda

Key Concepts and PiUalls of Mul@tenancy

Designing the Search Index

Defining the Cluster Topology

Integra@ng with your Applica@on

Q&A

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1

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Overview Key Concepts and Pi>alls of MulCtenant Search

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Defining Mul@tenancy

“Single so^ware instance serving mul@ple customers.”

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Benefits

•  Sharing of Resources •  Lower Costs •  Easier Horizontal Scaling • Quicker onboarding of new Customers • Data Aggrega@on •  Simpler Release Processes •  “Green”

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PiUalls & Risks

• Resource Sharing Limits • Requires more Customiza@on capabili@es • Higher Complexity • Data Security

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Search Engine

Topology

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Your Applica@on

Search Engine Search Cluster 1..N

Read/Write

Read

Hub/Tribe Node


Designing the Search Index

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Index Logical Granularity

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vs.


Shared Indices

•  Schema-‐less Index • Pros – True Global search – Intermixed Results across Customers/En@@es

• Cons – Cross Tenant Data Security – Weaker data separa@on – Index corrup@on can affect en@re Search – Ability of indexing data in parallel diminished

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Dedicated Indices

• Pros – Bejer data separa@on – More modular/portable – Bejer parallel indexing capabili@es

• Cons – More storage – Global search is more limited •  However, some search engines allow searching across indexes and even across clusters (Elas@csearch Tribe Node)

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Indexing Process & Storage

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Indexing Process & Storage

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Token Pointer

Droid 1, 2, 3

Look 2, 3

Rain 1

Doc 1: …

Doc 2: …

Doc 3: …


Indexing with Storage Enabled

“total”: 2,!“hits”: [!{!!“id”: 1,!!“text”: “These are not the <b>droids</b> you are looking for.”,!!“date”: “2014/10/8”!

},!{!!“id”: 2,!!“text”: “However, those are the <b>droids</b> you are looking for.”,!!“date”: “2014/10/8”!

} ]!

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Indexing with Storage Disabled

!“total”: 2,!“hits”: [!{!!“id”: 1,!

},!{!!“id”: 2,!

} ]!

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Storing and Retrieving Original Indexed Data

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Full Document IDs Only Pros •  Avoid hiong database on

your applica@on •  Snippet highligh@ng

•  Storage on Search Engine file system is light

•  Small response payload Cons •  Extra storage on Search

Engine file system •  Access control needs to be built in the index

•  Reliance on database for reading data to show users


Parent-‐child Rela@onships

• Defines 1-‐to-‐many rela@onship between entries in different indices • Convenient when pushing rela@onal data into Index • Parent can be updated without re-‐indexing children

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Customer Order 1 0..*


Mul@ple Languages

•  Leverage language auto-‐detec@on •  Leverage stop words •  Limit amount of stemming • Op@on: – Single entry in mul@ple languages • Merge value in different languages into single field •  Pro: Simple implementa@on. Search can be performed in any language •  Con: Match might include homonym in other languages

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Defining the Search Cluster Topology

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Node 2

Shards

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Node 1

1 2 3

4 5


Node 2

Replicas

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Node 1

1 2 3

4 5 1R 2R 3R 4R 5R


Cluster

• Approach depends on what your framework has to offer •  Elas@csearch provides a lot of support out of the box • Considera@ons: – Cluster Segmenta@on (Few Smaller vs Single Large?) – Geographical Distribu@on – Searching across Clusters – Write/Read Ra@o

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Hub

• Aware of All Clusters • Maintains map of Tenant -‐> Cluster •  Serves as discovery mechanism for the Client Applica@on • Able to create/pause/move/delete Tenants

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Hub Tenant Discovery Service

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Integra@ng with your Applica@on

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Indexing vs Querying

•  Expected load on wri@ng/reads • Depends on Problem Domain of Client Applica@on • Writes are expensive! – Specially if not done in bulk

• Reads are fairly cheap

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Ini@al Data Load/Full Re-‐index

• Perform Ac@ons in Bulk – Minimize overall number of Lucene Commits

• Consider enabling External “Versioning” – Safely parallelize indexing requests

• Keep track of documents that failed to index

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Incremental Indexing

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Incremental Indexing

• Monitor Indexing requests delay • Message customers accordingly – i.e.

Search Results might not include recently updated entries.


Disaster Recovery

•  Take advantage of what your Framework offers you – i.e. Replica@on in Elas@c Search

• Nightly Backups + Replay of changes since Backup crea@on • Avoid star@ng from scratch!

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Final Thoughts

• Recent Open-‐source Tooling (*cough* Elas%csearch) makes it easy • Consider Carefully: – Design and granularity of your tenant in the Search engine – Define En@@es and their Rela@onships – Sharding and Replica@on Schemes – Clustering Distribu@on •  i.e. per applica@on Installa@on, geographically, etc.

– High Availability Mechanisms

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Q&A Thank you!

Download - JDD2014: Multitenant Search - Pablo Barros

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