I started looking into ElasticSearch, and most examples of creating and reading involve POSTing data to the ElasticSearch server and then doing a GET to retrieve them.
Is this data that is POSTed stored separately by the ElasticSearch server? So, if I want to use ElasticSearch with MongoDB, does the raw data, not including the search indices, get stored twice (once copy for MongoDB and one for ElasticSearch)?
In conjunction with an answer to this question, a description or a link to a description of how ElasticSearch and the primary data store interact would be very helpful.
Yes, ElasticSearch can only search within its own data store, so a separate copy will be there.
You can use the mongodb connector to keep the data in elastic in sync with the mongo database: https://github.com/mongodb-labs/mongo-connector
Related
When I search in Elasticsearch, Elasticsearch send RESTAPI to original db?
Or Elasticsearch have orginal data?
I find Elasticsearch have indexing data. But I can't certain Elasticsearch have original data.
Elasticsearch is a database itself, so if you want some external data source to be in Elasticsearch (e.g: SQL Database) you need to index the data into Elasticsearch first, and then search against that data.
So no, the REST Api will not query against the original DB but against the data you have in Elasticsearch.
You can read more about the process here:
https://www.elastic.co/guide/en/cloud/current/ec-getting-started-search-use-cases-db-logstash.html
I am trying to Use my Elastic search server installed in my local machine to use Postman .i.e., With the help of Postman I want to Post Data and retrieve it with a get operation but unable to do it as I am getting error unknown key [High] for create index
So please help me with the same.
If you want to add a document to your index,
your url should look something like this ( for document ID 1 ) :
PUT http://localhost:9200/test/_doc/1
A good place to start :
https://www.elastic.co/guide/en/elasticsearch/reference/current/getting-started-index.html
For indexing document in the index
PUT http://localhost:9200/my_index/_doc/1
Retrieving indexed document
GET http://localhost:9200/my_index/_doc/1
Introduction:
Elasticsearch is a distributed, RESTful search and analytics engine capable of addressing a growing number of use cases. As the heart of the Elastic Stack, it centrally stores your data for lightning fast search, fine‑tuned relevancy, and powerful analytics that scale with ease.
Kibana is a free and open user interface that lets you visualize your Elasticsearch data and navigate the Elastic Stack. Do anything from tracking query load to understanding the way requests flow through your apps.
Logstash is a free and open server-side data processing pipeline that ingests data from a multitude of sources, transforms it, and then sends it to your favorite “stash.” .
Elasticsearch exposes itself through rest API so in this case you don't have to use logstash as we are directly adding data to elastic search
How to add it directly
you can create an index and type using :
{{url}}/index/type
where index is like a table and type is like just a unique data type that we will be storing to the index. Eg {{url}/movielist/movie
https://praveendavidmathew.medium.com/visualization-using-kibana-and-elastic-search-d04b388a3032
Elastic search is a search engine, according to Wikipedia. This implies it is not a database, and does not store the data it is indexing (but presumably does store its indexes)
There are presumably 2 ways to get data into Es. Log shipping or directly via api.
Let’s say my app wants to write an old fashioned log file entry:
Logger.error(now() + “ something bad happened in module “ + module + “;” + message”
This could either write to a file or put the data directly in es using a rest api.
If it was done via rest api, does es store the entire log message, in which case you dont need to waste disk writing the logs to files for compliance etc. Or does it only index the data, so you need to keep a separate copy? If you delete or move the original log file, how does es know, and is what it Deos store still usefull?
If you write to a log file, then use log stash or similar to “put the log data in es” does es store the entire log file as well as any indexes?
How does es parse or index arbitrary log files? Does it treat a log line as a single string, or does it require logs to have a specific format such as cvs or Jason?
Does anyone know of a resource with this key info?
Elasticsearch does store the data you are indexing.
When you ingest data into elasticsearch, this data is stored in one or more index and then it can be searched. To be able to search something with elasticsearch you need to store the data in elasticsearch, it can not for example search on external files.
In your example, if you have an app sending logs do elasticsearch, it will store the entire message you send and after it is in elasticsearch you don't need the original log anymore.
If you need to parse your documents in different fields you can do it before sending the log to elasticsearch as a json document, use logstash to do this or use an ingest pipeline in elasticsearch.
A good starting point to know more about how it works is the official documentation
I have a multi-tenant system, whereby each tenant gets their own Mongo database within a MongoDB deployment.
However for elastic search indexing, this all goes into one elastic instance via Mongoosastic, tagged with a TenantDB to keep data separated when searching.
Currently we have some of the same _id's reused across the multiple databases in test data for various config collections(Different document content, same _id), however this is causing a problem when syncing to elastic as although they're in separate databases when they come into elastic with the same Type and ID one of them gets dropped.
Is it possible to specify both the ID and TenantDB as the primary key?
Solution 1: You can search for multiple index in Elasticsearch. But, If you can not separate your index for database, you can follow like below method. While syncing your data to elasticsearch, use a pattern to create elastic document _id. For example, from mongoDb1 use mdb1_{mongo_id}, from mongoDb2 use mdb2_{mongo_id} , etc. This will be unique your _ids if you have not same id in same mongo database.
Solution 2: Separate your index.
Disclaimer: I am very new to ELK Stack, so this question can be very basic.
I am setting up ELK stack now. I have below basic questions about ElasticSearch.
What is the storage model elastic search is following?
For example Oracle is using relational model ,Alfresco is using "document model" and Apache Jackrabbit is using "hierarchial model"
2.Log data stored in elastic search is persistent/permanent ? Or ElasticSearch deletes log data after certain period?
3.How we will manage/backup this data?
4.Log/data files in Elastic Search is human-readable?
Any help/route to documentation will be appreciated.
the storage model is a Document model. Everything is a document. The documents are of a particular type and they are stored in an index.
Data send to ES is stored on disk. It can be then read, searched or deleted through a REST API.
The Data is managed through the rest API. Usually for log centralisation, the logs are stored in date-based index (one index for today, one for yesterday and so on), so to delete the logs from one day, you delete the relevant index. Curator can help in this case. ES offers a backup and restore module.
To access the data in ES, you'll have to use the REST API or use the Kibana client.
Documentation:
https://www.elastic.co/guide/en/elasticsearch/guide/current/index.html
https://www.elastic.co/guide/en/elasticsearch/reference/current/index.html