Im trying to deploy a Ruby on Rails app on a Ubuntu 16.04 EC2 server but is giving a error about the difference between max_gram and min_gram on Elasticsearch, i don't have any experience with Elasticsearch yet so im totally lost here and i need some guidance to do this and learn how to set it to avoid this problems in the future.
The first time i did the deploy there was a error refusing the connection to localhost:9200 so i had to check if the service was running and even check the firewall and at the end i had to do a clean install and configure everything on elasticsearch.yml and now is running and working but when i try to deploy again is giving me a error, did a lot of search on internet there is a lot of documentation but i still don't get where to set these values.
This is the error im getting on the log:
-----> Migrating database...
rake aborted!
StandardError: An error has occurred, all later migrations canceled:
[400] {"error":{"root_cause":[{"type":"illegal_argument_exception","reason":"The difference between max_gram and min_gram in NGram Tokenizer must be less than or equal to: [1] but was [49]. This limit can be set by changing the [index.max_ngram_diff] index level setting."}],"type":"illegal_argument_exception","reason":"The difference between max_gram and min_gram in NGram Tokenizer must be less than or equal to: [1] but was [49]. This limit can be set by changing the [index.max_ngram_diff] index level setting."},"status":400}
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/elasticsearch-transport-6.0.2/lib/elasticsearch/transport/transport/base.rb:205:in `__raise_transport_error'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/elasticsearch-transport-6.0.2/lib/elasticsearch/transport/transport/base.rb:323:in `perform_request'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/elasticsearch-transport-6.0.2/lib/elasticsearch/transport/transport/http/faraday.rb:20:in `perform_request'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/elasticsearch-transport-6.0.2/lib/elasticsearch/transport/client.rb:131:in `perform_request'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/elasticsearch-api-6.0.2/lib/elasticsearch/api/namespace/common.rb:21:in `perform_request'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/elasticsearch-api-6.0.2/lib/elasticsearch/api/actions/indices/create.rb:86:in `create'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/searchkick-3.0.2/lib/searchkick/index.rb:16:in `create'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/searchkick-3.0.2/lib/searchkick/index.rb:203:in `create_index'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/searchkick-3.0.2/lib/searchkick/index.rb:270:in `reindex_scope'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/searchkick-3.0.2/lib/searchkick/index.rb:196:in `reindex'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/searchkick-3.0.2/lib/searchkick/model.rb:59:in `searchkick_reindex'
/home/deploy/catalogindustry/releases/20190807135404/db/migrate/20180405153226_validated_true.rb:4:in `change'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/activerecord-5.0.7/lib/active_record/migration.rb:789:in `exec_migration'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/activerecord-5.0.7/lib/active_record/migration.rb:773:in `block (2 levels) in migrate'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/activerecord-5.0.7/lib/active_record/migration.rb:772:in `block in migrate'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/activerecord-5.0.7/lib/active_record/connection_adapters/abstract/connection_pool.rb:398:in `with_connection'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/activerecord-5.0.7/lib/active_record/migration.rb:771:in `migrate'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/activerecord-5.0.7/lib/active_record/migration.rb:951:in `migrate'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/activerecord-5.0.7/lib/active_record/migration.rb:1232:in `block in execute_migration_in_transaction'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/activerecord-5.0.7/lib/active_record/migration.rb:1302:in `ddl_transaction'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/activerecord-5.0.7/lib/active_record/migration.rb:1231:in `execute_migration_in_transaction'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/activerecord-5.0.7/lib/active_record/migration.rb:1203:in `block in migrate_without_lock'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/activerecord-5.0.7/lib/active_record/migration.rb:1202:in `each'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/activerecord-5.0.7/lib/active_record/migration.rb:1202:in `migrate_without_lock'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/activerecord-5.0.7/lib/active_record/migration.rb:1150:in `block in migrate'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/activerecord-5.0.7/lib/active_record/migration.rb:1319:in `with_advisory_lock'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/activerecord-5.0.7/lib/active_record/migration.rb:1150:in `migrate'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/activerecord-5.0.7/lib/active_record/migration.rb:1006:in `up'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/activerecord-5.0.7/lib/active_record/migration.rb:984:in `migrate'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/activerecord-5.0.7/lib/active_record/tasks/database_tasks.rb:163:in `migrate'
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/activerecord-5.0.7/lib/active_record/railties/databases.rake:58:in `block (2 levels) in '
/home/deploy/catalogindustry/shared/bundle/ruby/2.3.0/gems/rake-12.3.1/exe/rake:27:in `'
/home/deploy/.rbenv/versions/2.3.1/bin/bundle:23:in `load'
/home/deploy/.rbenv/versions/2.3.1/bin/bundle:23:in `
There is no index files on elasticsearch and there is nothing about this setting on the default template
I have faced a similar issue and below error message is clearly explaining the issue.
[400] {"error":{"root_cause":[{"type":"illegal_argument_exception","reason":"The difference between max_gram and min_gram in NGram Tokenizer must be less than or equal to: 1 but was [49]. This limit can be set by changing the [index.max_ngram_diff] index level setting."}],"type":"illegal_argument_exception","reason":"The difference between max_gram and min_gram in NGram Tokenizer must be less than or equal to: 1 but was [49]. This limit can be set by changing the [index.max_ngram_diff] index level setting."},"status":400}
Basically, by Default, the difference between max_gram and min_gram in NGram Tokenizer can't be more than 1 and if you want you to change this, then in your index settings you need to change it by adding below setting.
"max_ngram_diff" : "50" --> you can mention this number accoding to your requirement.
Below is my index settings, where you can see I have a difference of 47 in my max_gram and min_gram hence set max_ngram_diff to 50.
{
"settings": {
"index": {
"analysis": {
"analyzer": {
"prefix": {
"type": "custom",
"filter": [
"lowercaseFilter"
],
"tokenizer": "edgeNGramTokenizer"
}
},
"tokenizer": {
"edgeNGramTokenizer": {
"token_chars": [
"letter",
"digit"
],
"min_gram": "1",
"type": "edgeNGram",
"max_gram": "40"
},
"loginNGram": {
"type": "nGram",
"min_gram": "3",
"max_gram": "50"
}
}
},
"number_of_shards": "1",
"number_of_replicas": "0",
"max_ngram_diff" : "50"
}
}
}
Edit: Adding an official Elastic documentation, which explains that default length of max_gram is 2 and min_gram is 1, hence default difference between these can't be more than 1, hence the exception. And then snippet from the same doc
The index level setting index.max_ngram_diff controls the maximum allowed difference between max_gram and min_gram.