reindexing elastic search or updating indexes? - elasticsearch

I am now on elastic search, I cant figure out how to update elastic search index,type or document without deleting and reindexing? or is it the best way to achieve it?
So if I have products in my sql product table, should I better delete product type and reindex it or even entire DB as index on elasticsearc. what is the best use case and how can I achieve it?
I would like to do it with Nest preferably but if it is easier, ElasticSearch works for me as well.
Thanks

This can be a real challenge! Historic records in elasticsearch will need to be reindexed when the template changes. New records will automatically be formatted according to the template you specify.
Using this link has helped us a lot:
https://www.elastic.co/guide/en/elasticsearch/reference/current/indices-templates.html
You'll want to be sure to have the logstash filter set up to match the fields in your template.

Related

ElasticSearch updating all the documents

I am using elasticsearch to implement autocomplete feature. I have an api from which I get a list of all the values for autocomplete and I put those as documents in elastic search. The problem I am having is, those values could change, not very often but once a week.
I am thinking of deleting the all the documents and updating those again once a week, same as ttl of a cache. Is there any better way to achieve this?
Thank you in advance.
Maybe there are a bit more elegant than deleting and updating, you could create a new index xxxx_V2, putting new docs into xxxx_v2, and use the alias to make your app code link to the new index, then delete old index.
ideas is from https://www.elastic.co/blog/changing-mapping-with-zero-downtime.

ElasticSearch1.5 : Add new field in existing working Index

I have an existing index named as "MyIndex", which I am using to store a kind of data in ElasticSearch. That same index has millions of records. I am using ElasticSearch 1.5 version.
Now I have a new requirement for which I want to add two more fields in the same document which I am storing in "MyIndex" Index. Now I want to use both new schema and old schema documents in future.
What Can I do?
Can I inset new document in the same Index?
Are we need some changes in ElasticSearch mapping?
If we don't change anything, Is it affect on existing search capability?
Please help me to conclude this issue with your opinions.
Thanks in advance.
You can add new fields to existing index by updating mapping, but in many cases it would be just ok to index documents with new fields directly, and let ES infer types (although not always recommended) - but this will depend on what type of data you're indexing, and do you need special analyzers for strings or not.

How Alfresco and SOLR works with indexes queries

I have a doubt about how indexed properties works in Alfresco 4.1.6 with SOLR 1.4.
I use something like this for my queries:
SearchParameters sp = new SearchParameters();
sp.addStore(StoreRef.STORE_REF_WORKSPACE_SPACESSTORE);
sp.setLanguage(SearchService.LANGUAGE_FTS_ALFRESCO);
sp.setQuery(query);
ResultSet results = getSearchService().query(sp);
where query variable is something like this:
PATH:" /app:company_home/app:user_homes/cm:_x0030_123//*" AND
((#cm\:title:food) OR (#cm\:name:abcde) OR (TEXT:valles) OR
(#doc\:custom_property:"report") OR (#doc\:custom_property2:"report")
AND (#doc\:custom_property3:"report") AND TYPE:"{my.model}voc_document"
On my model.xml I specify what custom properties are indexed
<index enabled="true">
My question is... How works SOLR 1.4 with the indexes if I put on the search query two or more indexed properties? Like Oracle? Oracle try the best index and use only this. Or maybe SOLR combine all the indexed properties and uses all the index on the query?
I need this answer to determine how many indexes put on my model.xml. Maybe put a lot of indexes don't give me the best and efficient result and is better index only a few properties.
And finally, one question. I use LANGUAGE_FTS_ALFRESCO, but I can see that exists a LANGUAGE_SOLR_FTS_ALFRESCO. Is the same? I need to use the second if I use SOLR?
Thanks a lot!
Best regards
There is only one "index". Every field you mark as indexable (which is enabled by default) ends up in your solr index. Alfresco takes your query and sends it to SOLR for processing.
If you don't have a lot of documents, you can go ahead and index every field. By far the biggest impact on indexing and search is the full text index of the content field, which is enabled by default also.
LANGUAGE_FTS_ALFRESCO will use whatever index subsystem you have enabled. In later versions it may use SOLR or the database depending on your configuration. If you try to LANGUAGE_SOLR_FTS_ALFRESCO, it's forcing SOLR, so if you don't have solr enabled, you would have an error.
Regards!

What is the advantage of multiple index in elasticsearch?

Example for this is Logstash format. They formatted their index in elasticsearch with [logstash-]YYYY.MM.DD, where a new index will be used each day. The elasticsearch itself will be used by Kibana. Is there any reason why it's being done? What is the advantage?
Advantages that come to mind:
If you're looking for Tuesday's data, you can just look in Tuesday's index.
You can delete old data more easily.
If you want to modify the mappings, you can update the template and the changes will take effect the next day. It's your choice if you want to reindex the old data or not.

Do elasticsearch queries touch the DB?

Just starting to use elasticsearch with haystack in django using postgres, and I'm pretty happy with it so far.
I'm wondering if the search queries (filters) through ES will submit a query to the DB or do they use data gathered during indexing?
Given that I can delete the data in the DB and still search, the answer seems to be yes, the queries do not touch the DB but only touch the index.
Also, I found this documentation on the matter:
http://django-haystack.readthedocs.org/en/latest/best_practices.html#avoid-hitting-the-database
Further, this is also from the docs:
For example, one great way to leverage this is to pre-rendering an
object’s search result template DURING indexing. You define an
additional field, render a template with it and it follows the main
indexed record into the index. Then, when that record is pulled when
it matches a query, you can simply display the contents of that field,
which avoids the database hit.:

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