Elasticsearch is a distributed, scalable, and highly available search and analytics engine. The key points discussed in the document include proper cluster configuration, data mappings, and monitoring. The document outlines Elasticsearch's architecture including shards, replicas, and cluster topology. It also discusses modeling data through mappings, analysis, and handling relationships. Monitoring is important and can be done through Elasticsearch plugins, JVM tools, and the stats API.
This presentation contains differences between Elasticsearch and relational Databases. Along with that it also has some Glossary Of Elasticsearch and its basic operation.
Document databases are more flexible in many ways than relational databases and this presents both opportunities and challenges. Poorly designed document structures adversely affect performance, increase maintenance overhead, and lead to unnecessarily complex application code. This presentation describes 5 commonly used design patters in document databases: one-to-many, many-to-many, simple table inheritance, trees and lookup patterns.
Presented on 10/11/12 at the Boston Elasticsearch meetup held at the Microsoft New England Research & Development Center. This talk gave a very high-level overview of Elasticsearch to newcomers and explained why ES is a good fit for Traackr's use case.
This presentation contains differences between Elasticsearch and relational Databases. Along with that it also has some Glossary Of Elasticsearch and its basic operation.
Document databases are more flexible in many ways than relational databases and this presents both opportunities and challenges. Poorly designed document structures adversely affect performance, increase maintenance overhead, and lead to unnecessarily complex application code. This presentation describes 5 commonly used design patters in document databases: one-to-many, many-to-many, simple table inheritance, trees and lookup patterns.
Presented on 10/11/12 at the Boston Elasticsearch meetup held at the Microsoft New England Research & Development Center. This talk gave a very high-level overview of Elasticsearch to newcomers and explained why ES is a good fit for Traackr's use case.
IEEE IRI 16 - Clustering Web Pages based on Structure and Style SimilarityThamme Gowda
The structural similarity of HTML pages is measured by using Tree Edit Distance measure on DOM trees. The stylistic similarity is measured by using Jaccard similarity on CSS class names. An aggregated similarity measure is computed by combining structural and stylistic measures. A clustering method is then applied to this aggregated similarity measure to group the documents.
Data Management for Quantitative Biology - Database systems, May 7, 2015, Dr....QBiC_Tue
Forth lecture in our lecture series. Introduction to different biological databases. How to use mysql or nosql database in a research setting. What data repositories are available? How to use pride, peptide pilot and co. How to formulate queries for your custom databases. Dr. Marius Codrea Dr. Sven Nahnsen
Dan Sullivan - Data Analytics and Text Mining with MongoDB - NoSQL matters Du...NoSQLmatters
Data analysis is an exploratory process that requires a variety of tools and a flexible data store. Data analysis projects are easy to start but quickly become difficult to manage and error prone when depending on file-based data storage. Relational databases are poorly equipped to accommodate the dynamic demands complex analysis. This talk describes best practices for using MongoDB for analytics projects. Examples will be drawn from a large scale text mining project (approximately 25 million documents) that applies machine learning (neural networks and support vector machines) and statistical analysis. Tools discussed include R, Spark, Python scientific stack, and custom pre-processing scripts but the focus is on using these with the document database.
This is an introduction about the MongoDB. It includes basic MongoQueries. Not a advance level of presentation but provide nice information for the starters
NOSQL IMPLEMENTATION OF A CONCEPTUAL DATA MODEL: UML CLASS DIAGRAM TO A DOCUM...ijdms
The relational databases have shown their limits to the exponential increase in the volume of manipulated
and processed data. New NoSQL solutions have been developed to manage big data. These approaches are
an interesting way to build no-relational databases that can support large amounts of data. In this work,
we use conceptual data modeling (CDM), based on UML class diagrams, to create a logical structure of a
NoSQL database, taking account the relationships and constraints that determine how data can be stored
and accessible. The NoSQL logical data model obtained is based on the Document-Oriented Model
(DOM). to eliminate joins, a total and structured nesting is done on the collections of the documentoriented
database.
Rules of passage from the CDM to the Logical Oriented-Document Model (LODM) are also proposed in
this paper to transform the different types of associations between class. An application example of this
NoSQL BDD design method is realised to the case of an organization working in the e-commerce business
sector.
A Survey on Approaches for Frequent Item Set Mining on Apache HadoopIJTET Journal
Abstract— In data mining, association rule mining is one of the major techniques for discovering meaningful patterns from large collection of data. Discovering frequent item sets play an important role in mining association rules, sequence rules, web log mining and many other interesting patterns surrounded by complex data. Frequent Item set Mining is one of the classical data mining tribulations in most of the data mining applications. Apache Hadoop is a major innovation in the IT market place last decade. From modest beginnings Apache Hadoop has become a world-wide adoption in data centers. It brings parallel processing in hands of average programmer. This paper presents a literature analysis on different techniques for mining frequent item sets and frequent item sets on Hadoop.
Annotating search results from web databases-IEEE Transaction Paper 2013Yadhu Kiran
Abstract—An increasing number of databases have become web accessible through HTML form-based search interfaces. The data units returned from the underlying database are usually encoded into the result pages dynamically for human browsing. For the encoded data units to be machine processable, which is essential for many applications such as deep web data collection and Internet comparison shopping, they need to be extracted out and assigned meaningful labels. In this paper, we present an automatic
annotation approach that first aligns the data units on a result page into different groups such that the data in the same group have the same semantic. Then, for each group we annotate it from different aspects and aggregate the different annotations to predict a final annotation label for it. An annotation wrapper for the search site is automatically constructed and can be used to annotate new result pages from the same web database. Our experiments indicate that the proposed approach is highly effective.
Automating Relational Database Schema Design for Very Large Semantic DatasetsThomas Lee
Many semantic datasets or RDF datasets are very large but have no pre-defined data structures. Triple stores are commonly used as RDF databases yet they cannot achieve good query performance for large datasets owing to excessive self-joins. Recent research work proposed to store RDF data in column-based databases. Yet, some study has shown that such an approach is not scalable to the number of predicates. The third common approach is to organize an RDF data set in different tables in a relational database. Multiple “correlated” predicates are maintained in the same table called property table so that table-joins are not needed for queries that involve only the predicates within the table. The main challenge for the property table approach is that it is infeasible to manually design good schemas for the property tables of a very large RDF dataset. We propose a novel data-mining technique called Attribute Clustering by Table Load (ACTL) that clusters a given set of attributes into correlated groups, so as to automatically generate the property table schemas. While ACTL is an NP-complete problem, we propose an agglomerative clustering algorithm with several effective pruning techniques to approximate the optimal solution. Experiments show that our algorithm can efficiently mine huge datasets (e.g., Wikipedia Infobox data) to generate good property table schemas, with which queries generally run faster than with triple stores and column-based databases.
To Get any Project for CSE, IT ECE, EEE Contact Me @ 09849539085, 09966235788 or mail us - ieeefinalsemprojects@gmail.co¬m-Visit Our Website: www.finalyearprojects.org
A Data Ecosystem to Support Machine Learning in Materials ScienceGlobus
This presentation was given at the 2019 GlobusWorld Conference in Chicago, IL by Ben Blaiszik from University of Chicago and Argonne National Laboratory Data Science and Learning Division.
Practical Large Scale Experiences with Spark 2.0 Machine Learning: Spark Summ...Spark Summit
Spark 2.0 provided strong performance enhancements to the Spark core while advancing Spark ML usability to use data frames. But what happens when you run Spark 2.0 machine learning algorithms on a large cluster with a very large data set? Do you even get any benefit from using a very large data set? It depends. How do new hardware advances affect the topology of high performance Spark clusters. In this talk we will explore Spark 2.0 Machine Learning at scale and share our findings with the community.
As our test platform we will be using a new cluster design, different from typical Hadoop clusters, with more cores, more RAM and latest generation NVMe SSD’s and a 100GbE network with a goal of more performance, in a more space and energy efficient footprint.
IEEE IRI 16 - Clustering Web Pages based on Structure and Style SimilarityThamme Gowda
The structural similarity of HTML pages is measured by using Tree Edit Distance measure on DOM trees. The stylistic similarity is measured by using Jaccard similarity on CSS class names. An aggregated similarity measure is computed by combining structural and stylistic measures. A clustering method is then applied to this aggregated similarity measure to group the documents.
Data Management for Quantitative Biology - Database systems, May 7, 2015, Dr....QBiC_Tue
Forth lecture in our lecture series. Introduction to different biological databases. How to use mysql or nosql database in a research setting. What data repositories are available? How to use pride, peptide pilot and co. How to formulate queries for your custom databases. Dr. Marius Codrea Dr. Sven Nahnsen
Dan Sullivan - Data Analytics and Text Mining with MongoDB - NoSQL matters Du...NoSQLmatters
Data analysis is an exploratory process that requires a variety of tools and a flexible data store. Data analysis projects are easy to start but quickly become difficult to manage and error prone when depending on file-based data storage. Relational databases are poorly equipped to accommodate the dynamic demands complex analysis. This talk describes best practices for using MongoDB for analytics projects. Examples will be drawn from a large scale text mining project (approximately 25 million documents) that applies machine learning (neural networks and support vector machines) and statistical analysis. Tools discussed include R, Spark, Python scientific stack, and custom pre-processing scripts but the focus is on using these with the document database.
This is an introduction about the MongoDB. It includes basic MongoQueries. Not a advance level of presentation but provide nice information for the starters
NOSQL IMPLEMENTATION OF A CONCEPTUAL DATA MODEL: UML CLASS DIAGRAM TO A DOCUM...ijdms
The relational databases have shown their limits to the exponential increase in the volume of manipulated
and processed data. New NoSQL solutions have been developed to manage big data. These approaches are
an interesting way to build no-relational databases that can support large amounts of data. In this work,
we use conceptual data modeling (CDM), based on UML class diagrams, to create a logical structure of a
NoSQL database, taking account the relationships and constraints that determine how data can be stored
and accessible. The NoSQL logical data model obtained is based on the Document-Oriented Model
(DOM). to eliminate joins, a total and structured nesting is done on the collections of the documentoriented
database.
Rules of passage from the CDM to the Logical Oriented-Document Model (LODM) are also proposed in
this paper to transform the different types of associations between class. An application example of this
NoSQL BDD design method is realised to the case of an organization working in the e-commerce business
sector.
A Survey on Approaches for Frequent Item Set Mining on Apache HadoopIJTET Journal
Abstract— In data mining, association rule mining is one of the major techniques for discovering meaningful patterns from large collection of data. Discovering frequent item sets play an important role in mining association rules, sequence rules, web log mining and many other interesting patterns surrounded by complex data. Frequent Item set Mining is one of the classical data mining tribulations in most of the data mining applications. Apache Hadoop is a major innovation in the IT market place last decade. From modest beginnings Apache Hadoop has become a world-wide adoption in data centers. It brings parallel processing in hands of average programmer. This paper presents a literature analysis on different techniques for mining frequent item sets and frequent item sets on Hadoop.
Annotating search results from web databases-IEEE Transaction Paper 2013Yadhu Kiran
Abstract—An increasing number of databases have become web accessible through HTML form-based search interfaces. The data units returned from the underlying database are usually encoded into the result pages dynamically for human browsing. For the encoded data units to be machine processable, which is essential for many applications such as deep web data collection and Internet comparison shopping, they need to be extracted out and assigned meaningful labels. In this paper, we present an automatic
annotation approach that first aligns the data units on a result page into different groups such that the data in the same group have the same semantic. Then, for each group we annotate it from different aspects and aggregate the different annotations to predict a final annotation label for it. An annotation wrapper for the search site is automatically constructed and can be used to annotate new result pages from the same web database. Our experiments indicate that the proposed approach is highly effective.
Automating Relational Database Schema Design for Very Large Semantic DatasetsThomas Lee
Many semantic datasets or RDF datasets are very large but have no pre-defined data structures. Triple stores are commonly used as RDF databases yet they cannot achieve good query performance for large datasets owing to excessive self-joins. Recent research work proposed to store RDF data in column-based databases. Yet, some study has shown that such an approach is not scalable to the number of predicates. The third common approach is to organize an RDF data set in different tables in a relational database. Multiple “correlated” predicates are maintained in the same table called property table so that table-joins are not needed for queries that involve only the predicates within the table. The main challenge for the property table approach is that it is infeasible to manually design good schemas for the property tables of a very large RDF dataset. We propose a novel data-mining technique called Attribute Clustering by Table Load (ACTL) that clusters a given set of attributes into correlated groups, so as to automatically generate the property table schemas. While ACTL is an NP-complete problem, we propose an agglomerative clustering algorithm with several effective pruning techniques to approximate the optimal solution. Experiments show that our algorithm can efficiently mine huge datasets (e.g., Wikipedia Infobox data) to generate good property table schemas, with which queries generally run faster than with triple stores and column-based databases.
To Get any Project for CSE, IT ECE, EEE Contact Me @ 09849539085, 09966235788 or mail us - ieeefinalsemprojects@gmail.co¬m-Visit Our Website: www.finalyearprojects.org
A Data Ecosystem to Support Machine Learning in Materials ScienceGlobus
This presentation was given at the 2019 GlobusWorld Conference in Chicago, IL by Ben Blaiszik from University of Chicago and Argonne National Laboratory Data Science and Learning Division.
Practical Large Scale Experiences with Spark 2.0 Machine Learning: Spark Summ...Spark Summit
Spark 2.0 provided strong performance enhancements to the Spark core while advancing Spark ML usability to use data frames. But what happens when you run Spark 2.0 machine learning algorithms on a large cluster with a very large data set? Do you even get any benefit from using a very large data set? It depends. How do new hardware advances affect the topology of high performance Spark clusters. In this talk we will explore Spark 2.0 Machine Learning at scale and share our findings with the community.
As our test platform we will be using a new cluster design, different from typical Hadoop clusters, with more cores, more RAM and latest generation NVMe SSD’s and a 100GbE network with a goal of more performance, in a more space and energy efficient footprint.
Analyzing Semi-Structured Data At Volume In The CloudRobert Dempsey
Presentation from Snowflake Computing at the November 2015 Data Wranglers DC meetup.
The Cloud, Mobile and Web Applications are producing semi-structured data at an unprecedented rate. IT professionals continue to struggle capturing, transforming, and analyzing these complex data structures mixed with traditional relational style datasets using conventional MPP and/or Hadoop infrastructures. Public cloud infrastructures such as Amazon and Azure provide almost unlimited resources and scalability to handle both structured and semi-structured data (XML, JSON, AVRO) at Petabyte scale. These new capabilities coupled with traditional data management access methods such as SQL allow organizations and businesses new opportunities to leverage analytics at an unprecedented scale while greatly simplifying data pipeline architectures and providing an alternative to the "data lake".
Building a Dataset Search Engine with Spark and Elasticsearch: Spark Summit E...Spark Summit
Elasticsearch provides native integration with Apache Spark through ES-Hadoop. However, especially during development, it is at best cumbersome to have Elasticsearch running in a separate machine/instance. Leveraging Spark Cluster with Elasticsearch Inside it is possible to run an embedded instance of Elasticsearch in the driver node of a Spark Cluster. This opens up new opportunities to develop cutting-edge applications. One such application is Dataset Search.
Oscar will give a demo of a Dataset Search Engine built on Spark Cluster with Elasticsearch Inside. Motivation is that once Elasticsearch is running on Spark it becomes possible and interesting to have the Elasticsearch in-memory instance join an (existing) Elasticsearch cluster. And this in turn enables indexing of Datasets that are processed as part of Data Pipelines running on Spark. Dataset Search and Data Management are R&D topics that should be of interest to Spark Summit East attendees who are looking for a way to organize their Data Lake and make it searchable.
Entity relationship model, Components of ER model, Mapping E-R model to Relational schema, Network and Object-Oriented Data models, Storage Strategies: Detailed Storage Architecture, Storing Data, Magnetic Disk, RAID, Other Disks, Magnetic Tape, Storage Access, File & Record Organization, File Organizations & Indexes, Order Indices, B+ Tree Index Files, Hashing Data Dictionary
Webinar Slides: Tungsten Replicator for Elasticsearch - Real-time data loadin...Continuent
Elasticsearch provides a quick and easy method to aggregate data, whether you want to use it for simplifying your search across multiple depots and databases, or as part of your analytics stack. Getting the data from your transactional engines into Elasticsearch is something that can be achieved within your application layer with all of the associated development and maintenance costs. Instead, offload the operation and simplify your deployment by using direct data replication to handle the insert, update and delete processes.
AGENDA
- Basic replication model
- How to concentrate data from multiple sources
- How the data is represented within Elasticsearch
- Customizations and configurations available to tailor the data format
- Filters and data modifications available
Global introduction to elastisearch presented at BigData meetup.
Use cases, getting started, Rest CRUD API, Mapping, Search API, Query DSL with queries and filters, Analyzers, Analytics with facets and aggregations, Percolator, High Availability, Clients & Integrations, ...
Elasticsearch as a search alternative to a relational databaseKristijan Duvnjak
The volume of data that we are working with is growing every day, the size of data is pushing us to find new intelligent solutions for problem’s put in front of us. Elasticsearch server has proved it self as an excellent full text search solution for big volume’s of data.
Multi-model Databases and Tightly Integrated PolystoresJiaheng Lu
One of the most challenging issues in the era of Big Data is the
“Variety” of the data. In general, there are two solutions to directly manage multi-model data currently: a single integrated multi-model database system or a tightly-integrated middleware over multiple single-model data stores. In this tutorial, we review and compare these two approaches giving insights on their advantages, tradeoffs, and research opportunities. In particular, we dive into four key aspects of technology for both types of systems, namely (1) theoretical foundation of multi-model data management, (2) storage strategies for multi-model data, (3) query languages across models, and (4) query evaluation and its optimization. We provide a comparison of performance for the two approaches and discuss related open problems and remaining challenges.
A (vintage) presentation about a database system for the study of gene expression data. Including distributed metadata annotation and some interactive analytics. Some ideas are still actual today.
A brief presentation outlining the basics of elasticsearch for beginners. Can be used to deliver a seminar on elasticsearch.(P.S. I used it) Would Recommend the presenter to fiddle with elasticsearch beforehand.
Data Centers - Striving Within A Narrow Range - Research Report - MCG - May 2...pchutichetpong
M Capital Group (“MCG”) expects to see demand and the changing evolution of supply, facilitated through institutional investment rotation out of offices and into work from home (“WFH”), while the ever-expanding need for data storage as global internet usage expands, with experts predicting 5.3 billion users by 2023. These market factors will be underpinned by technological changes, such as progressing cloud services and edge sites, allowing the industry to see strong expected annual growth of 13% over the next 4 years.
Whilst competitive headwinds remain, represented through the recent second bankruptcy filing of Sungard, which blames “COVID-19 and other macroeconomic trends including delayed customer spending decisions, insourcing and reductions in IT spending, energy inflation and reduction in demand for certain services”, the industry has seen key adjustments, where MCG believes that engineering cost management and technological innovation will be paramount to success.
MCG reports that the more favorable market conditions expected over the next few years, helped by the winding down of pandemic restrictions and a hybrid working environment will be driving market momentum forward. The continuous injection of capital by alternative investment firms, as well as the growing infrastructural investment from cloud service providers and social media companies, whose revenues are expected to grow over 3.6x larger by value in 2026, will likely help propel center provision and innovation. These factors paint a promising picture for the industry players that offset rising input costs and adapt to new technologies.
According to M Capital Group: “Specifically, the long-term cost-saving opportunities available from the rise of remote managing will likely aid value growth for the industry. Through margin optimization and further availability of capital for reinvestment, strong players will maintain their competitive foothold, while weaker players exit the market to balance supply and demand.”
4. Introduction (1): Elasticsearch definition and key points
Elasticsearch is not a NO-SQL database
Elasticsearch is not a Search Engine (uses Apache Lucene)
Elasticsearch is a server used to search & analyze data in real time.
• It is distributed, scalable and highly available.
• It is meant for real-time search and analytics capabilities.
• It comes with a sophisticated RESTful API.
3 key points in Elasticsearch:
• Proper cluster configuration and architecture
• Proper Data Mappings
• Proper JVM and cluster monitoring
Elasticsearch is fragile, delicate, sensitive, frail and tricky
“With great power comes great responsibility” Benjamin Parker
5. Introduction (2): Apache Lucene Inverted indexes
1. Spiderman is my favourite hero
2. Batman is a hero
3. Ernesto is a hero better than Spiderman and Batman
Term Count Docs
Spiderman 2 1, 3
is 3 1,2,3
my 1 1
favourite 1 1
hero 3 1,2,3
Batman 2 2,3
a 2 2,3
Ernesto 1 3
better 1 3
than 1 3
and 1 3
7. Configuration (1): Shards and Replica
• Shard: Apache Lucene Index
• Replica: copy of a shard
• Elasticsearch Index: 1 or more shards
• Question 1: How many shards do we need? And how many replicas?
• Question 2: Does it make sense to have one shard and its corresponding replica in the
same node?
• Question 3: Is it useful having a 1-node cluster with "number_of_replicas": 1?
• General rule:
– Max Number of nodes = number of shards * (number of replica + 1)
8. Configuration (2)
• Dedicated memory should not be more than 50% of the total memory available.
– Example 16g:
• ./bin/elasticsearch -Xmx8g -Xms8g
• export ES_HEAP_SIZE=8g
– Xms and max Xmx should be the same
• Do not give more than 32 GB!
– ( http://www.elastic.co/guide/en/elasticsearch/guide/master/heap-
sizing.html#compressed_oops)
• Enable mlockall to avoid memory swapping:
– bootstrap.mlockall: true
• Use SSD disks
• Change logs path:
– path.logs: /var/log/elasticsearch
9. Configuration (3): cluster topology (1)
• A well designed topology will make the cluster to:
– Increase search speed
– Reduce CPU consumption
– Reduce memory consumption
– Accept more concurrent requests per second
– Reduce probability of split brain
– Reduce probability of other errors in general.
– Reduce hardware costs
• Data nodes and 2 types of non-data nodes:
– data nodes
• http.enabled: false
• node.data: true
• node.master: false
– dedicated master nodes
• http.enabled: false
• node.data: false
• node.master: true
– client nodes. Smart load balancers
• http.enabled: true
• node.data: false
• node.master: false
10. Configuration (4): cluster topology (2)
With this configuration we can use
machines with different hardware
configuration for every type of node.
This way we can save a lot
of money invested in hardware!!
Example of cluster topology with 2
HTTP nodes, 2 master nodes and
1 to X data nodes
12. Modeling the data (1): Mapping
• Mapping is the process of defining how a document should be mapped to
the Search Engine
– Default Dynamic Mapping
• An index may store documents of different "mapping types”
• Mapping types are a way to divide the documents in an index into logical
groups. Think of it as tables in a database
• Components:
– Fields: _id, _type, _source, _all, _parent, _index, _size,…
– Types: the datatype for each field in a document (eg strings, numbers, objects
etc)
• Core Types: string, integer/long, float/double, boolean, and null.
• Array
• Object
• Nested
• IP
• Geo Point
• Geo Shape
• Attachment
13. Modeling the data (2): Analysis
• Analysis is a process that consists of the following:
– First, tokenizing a block of text into individual terms suitable for use in an inverted index,
– Then normalizing these terms into a standard form to improve their “searchability,” or recall
• This job is performed by analyzers. An analyzer is really just a wrapper that
combines three functions into a single package:
– 0 or more Character filters
– 1 Tokenizer
– 0 or more Token filters
• Analysis is performed to both:
– break indexed (analyzed) fields when a document is indexed
– process query strings
• Elasticsearch provides many character filters, tokenizers, and token filters
out of the box. These can be combined to create custom analyzers
suitable for different purposes.
14. Modeling the data (3): Analysis steps example
Original sentence: Batman & Robin aren´t my favourite heroes
Batman
and
Robin
aren´t
my
favourite
heroes
1st) Character filter: Batman and Robin aren´t my favourite heroes
2nd) Tokenizer:
3rd) Token Filter:
batman
--
robin
aren
my
favourite
heroes
Indexed:
15. Modeling the data (4): Handling relationships
Handling relationships between entities is not as obvious as it is with a
dedicated relational store. The golden rule of a relational database—normalize
your data—does not apply to Elasticsearch.
Four common techniques are used to manage relational data in Elasticsearch:
• Application-side joins
• Data denormalization
• Nested objects
• Parent/child relationships
16. PUT /my_index/user/1
{
"name": "John Smith",
"email": "john@smith.com",
"dob": "1970/10/24"
}
PUT /my_index/blogpost/2
{
"title": "Relationships",
"body": "It's complicated...",
"user": 1
}
Modeling the data (5): Handling relationships – Application-side joins
We can (partly) emulate a relational database by implementing joins in our application:
Problem: This approach is only suitable when the first entity (the user in this example)
has a small number of documents and, preferably, they seldom change.
17. PUT /my_index/user/1
{
"name": "John Smith",
"email": "john@smith.com",
"dob": "1970/10/24"
}
PUT /my_index/blogpost/2
{
"title": "Relationships",
"body": "It's complicated...",
"user": {
"id": 1,
"name": "John Smith"
}
}
Modeling the data (6): Handling relationships – Data denormalization
Having redundant copies of data in each document that requires access to it removes the need for
joins:
Problem: if we want to update the name, or remove a user object, we have to reindex
also the whole blogpost document.
18. PUT /my_index/blogpost/1
{
"title": "Nest eggs",
"body": "Making your money work...",
"tags": [ "cash", "shares" ],
"comments": [
{
"name": "John Smith",
"comment": "Great article",
"age": 28,
"stars": 4,
"date": "2014-09-01"
},
{
"name": "Alice White",
"comment": "More like this please",
"age": 31,
"stars": 5,
"date": "2014-10-22"
}
]
}
Modeling the data (7): Handling relationships – Nested objects
Given the fact that creating, deleting, and updating a single document in Elasticsearch is atomic, it
makes sense to store closely related entities within the same document:
Problem: As with denormalization, to update, add, or remove a nested object, we have to reindex the
whole document also the whole blogpost document.
19. Find children by parent:
GET /company/employee/_search
{
"query": {
"has_parent": {
"type": "branch",
"query": {
"match": {
"country": "UK"
}
}
}
}
}
Index a child document:
PUT /company
{
"mappings": {
"branch": {},
"employee": {
"_parent": {
"type": "branch"
}
}
}
}
Modeling the data (8): Handling relationships – Parent/child relationship
The parent-child functionality allows you to associate one document type with another, in a one-to-many relationship—
one parent to many children. Advantages:
• The parent document can be updated without reindexing the children.
• Child documents can be added, changed, or deleted without affecting either the parent or other children.
• Child documents can be returned as the results of a search request.
Find parents by children:
GET /company/branch/_search
{
"query": {
"has_child": {
"type": "employee",
"query": {
“term": {
“name": “John"
}
}
}
}
}