Box uses the Solr search platform to power content search across its 25 million+ users. Some key aspects of Box's search implementation with Solr include: 1) The Solr index is sharded or split across multiple shards for high availability and scalability, with each file identifier mapped to a specific shard. 2) Search queries are handled by a front-end load balancer that distributes queries across multiple search head nodes for high availability. 3) Solr documents contain metadata like file owner, parent folders, and extracted text to support search by content, ownership, and folder structure.

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June 2014
Box + Solr = Content Search for
Business

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Wei Zhao
Box backend engineer
wzhao@box.com

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to make organizations more productive,
competitive and collaborative by connecting
people and their most important information
Box mission

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25MM+
Users
225K+
Businesses
99%
Fortune 500

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Box search mission is to make user content
easy to discover.

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10Billion+
Documents
10TB+
Index size
100M+
Daily requests
Box uses Solr for search

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Quick Search

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Quick Search

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Full Search

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Sharding – splitting the index
Agenda
Highly available search
A few more things
1
2
3
4
5 Q&A
Currently working on

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We shard things

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Shard ID = File ID % Total Shards

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Multi-tenant – One big logical index for all users
Solr index
Shard1 Shard2 Shard3 ShardN

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Search scope

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File ID: 12345
OwnerID: user1
Parent Folders IDs: folder1, folder2
File Name: Solr.ppt
File Content: blah
......
A typical Solr Document

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Owner: User1
Parent: Folder1
Owner: User2
Parent: Folder3
Owner: User2
Parent: Folder2
Owner: User1
Parent:
Folder1
Folder4
File 1 File 2
File 3 File 4

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User1 with no share folder
Owner: User1
Parent: Folder1
Owner: User2
Parent: Folder3
Owner: User2
Parent: Folder2
Owner: User1
Parent:
Folder1
Folder4
File 1 File 2
File 3 File 4

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User2 shares Folder2 with User1
Owner: User1
Parent: Folder1
Owner: User2
Parent: Folder3
Owner: User2
Parent: Folder2
Owner: User1
Parent:
Folder1
Folder4
File 1 File 2
File 3 File 4

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User2 shares Folder2 with User1
Owner: User1
Parent: Folder1
Owner: User2
Parent: Folder3
Owner: User2
Parent: Folder2
Owner: User1
Parent:
Folder1
Folder4
File 1 File 2
File 3 File 4

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User2 shares Folder2 with User1
Owner: User1
Parent: Folder1
Owner: User2
Parent: Folder3
Owner: User2
Parent: Folder5
Owner: User1
Parent:
Folder1
Folder4
File 1 File 2
File 3 File 4
Removed
out of
Folder2

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User2 shares Folder2 with User1
Owner: User1
Parent: Folder1
Owner: User2
Parent: Folder3
Owner: User2
Parent: Folder5
Owner: User1
Parent:
Folder1
Folder4
File 1 File 2
File 3 File 4
Removed
out of
Folder2

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Highly Available Search

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• Index is highly available
• Search functionality is highly available

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Index workflow

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Box
Front
End
Upload
Index Queue
Queue 1
Queue 2
Queue 3
Indexer 1
Indexer 3
Indexer 2
MySQL
Index1
Index2
Index2

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Search workflow

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Box
Front
End
query HA
Proxy
Head
node
HA Proxy
1 2 3 N
Box
Front
End
query
HA
Proxy
Head
node
HA Proxy
1 2 3 N
Data center boundary

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A few more things

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File Content Search

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Box
Front
End
Upload
MySQL Box File
Storage
Indexer
Solr
Index
Text Extraction
Extracted
Text

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Multi-language support

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Raw file
content
Language
detector
English tokenizer
Spanish tokenizer
Japanese tokenizer
German tokenizer
file_content_en
File_content_es
{hola}
file_content_ja
.
.
.
.
File_content_de

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To Dos
• Scale language support
• Support document with mixed languages

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Search Warm-up

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• Front end informs backend to warm up on keyboard focus
• Backend prepares the search filter and caches it in a search session
• Backend sends a warm-up query to Solr

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What we are working on

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• Search suggestions
• Search operators
• Use machine learning to influence ranking
• Logical sharding
Things we are working on

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Question?

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Contact: wzhao@box.com
We are hiring!