Jiří Materna, Head of Research
The Czech number one Internet company
Seznam.cz
www.seznam.cz
Internet portal with tens of high-quality services:• Web search (web search engine successfully competing with Google)
• Specialized search (Czech companies, e-shops)
• E-mail (the most popular free e-mail in the Czech market)
• News (covering business, politics, lifestyle, sport, whether, TV schedules, etc.)
• Entertainment (video and music online streaming)
• On-line maps (more detailed than Google maps)
• Sklik.cz (advertising system)
• And others…
What is Seznam.cz
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www.seznam.cz
• More than 1000 employees• Revenue 2.8 billion CZK (108 mil. EUR)• 2.4 million people visit Seznam.cz every day• 1.5 billion crawled web pages
-- 45 % English
-- 37 % Czech
-- 7.7 % Slovak
-- 2.3 % German
-- 8 % Others
• 500 queries per second in peak hours
Seznam.cz in numbers
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www.seznam.cz
Search engine architecture
@JiriMaterna
www.seznam.cz
• Query understanding• Graph representation:
- AND
- OR
- optional
- other relations
Query Expander
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www.seznam.cz
Search aggregators
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• Deduplication• Document sub-results• SERP restrictions• Caching
www.seznam.cz
• RC-Rank – Boosted regression oblivious trees• Hundreds of features• Our own quality measure
Ranking
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www.seznam.cz
Index & Indexer
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• Indexing: complete, daily, fresh
• Data structures:
word barrel – stores the inverted index
document barrel – stores document features
title barrel – stores processed web pages content and metadata
others – query site barrel, site barrel, link barrel, qds barrel, query url barrel, …
www.seznam.cz
• Hadoop, Giraffe, Yarn• 50 mil. documents every day• 1.5 bil. documents out of 50 bil. known
documents stored• duplicity detection
Downloader & document database
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www.seznam.cz
• Joint projects• Providing our technology• Sharing data (MetaCentrum) • …
Possible models of cooperation
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www.seznam.cz
Jiří Materna, Head of Research, [email protected]
Thank you for your attention.
@JiriMaterna