{"action":"created","issue":{"url":"https://api.github.com/repos/elasticsearch/elasticsearch/issues/8142","labels_url":"https://api.github.com/repos/elasticsearch/elasticsearch/issues/8142/labels{/name}","comments_url":"https://api.github.com/repos/elasticsearch/elasticsearch/issues/8142/comments","events_url":"https://api.github.com/repos/elasticsearch/elasticsearch/issues/8142/events","html_url":"https://github.com/elasticsearch/elasticsearch/issues/8142","id":46105054,"number":8142,"title":"Mappings: Ensure that reindexing is always possible","user":{"login":"jpountz","id":299848,"avatar_url":"https://avatars.githubusercontent.com/u/299848?v=3","gravatar_id":"","url":"https://api.github.com/users/jpountz","html_url":"https://github.com/jpountz","followers_url":"https://api.github.com/users/jpountz/followers","following_url":"https://api.github.com/users/jpountz/following{/other_user}","gists_url":"https://api.github.com/users/jpountz/gists{/gist_id}","starred_url":"https://api.github.com/users/jpountz/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/jpountz/subscriptions","organizations_url":"https://api.github.com/users/jpountz/orgs","repos_url":"https://api.github.com/users/jpountz/repos","events_url":"https://api.github.com/users/jpountz/events{/privacy}","received_events_url":"https://api.github.com/users/jpountz/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/elasticsearch/elasticsearch/labels/discuss","name":"discuss","color":"fbca04"},{"url":"https://api.github.com/repos/elasticsearch/elasticsearch/labels/enhancement","name":"enhancement","color":"4a4ea8"},{"url":"https://api.github.com/repos/elasticsearch/elasticsearch/labels/v2.0.0","name":"v2.0.0","color":"dddddd"}],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":11,"created_at":"2014-10-17T14:26:19Z","updated_at":"2015-02-24T13:20:50Z","closed_at":null,"body":"Our mappings are very permissive in terms of what can be enabled or disabled, and in particular it is possible to disable the `_source`. This can be problematic if at some point you need to perform a change that requires reindexing (eg. an analyzer change) because this means that the data needs to be pulled again from another data source.\r\n\r\nInstead, we could disable some mappings options in order to make sure that we always have all the information needed to reindex (eg. with [client helpers](http://elasticsearch-py.readthedocs.org/en/latest/helpers.html#elasticsearch.helpers.reindex)). Here are the settings that we would need to enforce:\r\n - `_source` is enabled and stored\r\n - `_timestamp`, `_ttl`, `_routing`, `_parent` are stored\r\n\r\nRelates to #8870"},"comment":{"url":"https://api.github.com/repos/elasticsearch/elasticsearch/issues/comments/75754710","html_url":"https://github.com/elasticsearch/elasticsearch/issues/8142#issuecomment-75754710","issue_url":"https://api.github.com/repos/elasticsearch/elasticsearch/issues/8142","id":75754710,"user":{"login":"brwe","id":4320215,"avatar_url":"https://avatars.githubusercontent.com/u/4320215?v=3","gravatar_id":"","url":"https://api.github.com/users/brwe","html_url":"https://github.com/brwe","followers_url":"https://api.github.com/users/brwe/followers","following_url":"https://api.github.com/users/brwe/following{/other_user}","gists_url":"https://api.github.com/users/brwe/gists{/gist_id}","starred_url":"https://api.github.com/users/brwe/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/brwe/subscriptions","organizations_url":"https://api.github.com/users/brwe/orgs","repos_url":"https://api.github.com/users/brwe/repos","events_url":"https://api.github.com/users/brwe/events{/privacy}","received_events_url":"https://api.github.com/users/brwe/received_events","type":"User","site_admin":false},"created_at":"2015-02-24T13:20:50Z","updated_at":"2015-02-24T13:20:50Z","body":"Disabling does reduce the size on disk:\r\nhttps://groups.google.com/forum/?utm_medium=email&utm_source=footer#!msg/elasticsearch/cZ7tkx8HZ70/AOFAt42mNt0J\r\nI think when people store the raw data outside es in some secondary store then we should not force them to store the source in es again or even make it hard to disable it."}}