Github user mmiklavc commented on a diff in the pull request: https://github.com/apache/metron/pull/840#discussion_r159680299 --- Diff: metron-platform/metron-elasticsearch/README.md --- @@ -33,7 +42,217 @@ For instance, an `es.date.format` of `yyyy.MM.dd.HH` would have the consequence roll hourly, whereas an `es.date.format` of `yyyy.MM.dd` would have the consequence that the indices would roll daily. -## Using Metron with Elasticsearch 2.x +## Upgrading to 5.6.2 + +Users should be prepared to re-index when migrating from Elasticsearch 2.3.3 to 5.6.2. There are a number of template changes, most notably around +string type handling, that may cause issues when upgrading. + +[https://www.elastic.co/guide/en/elasticsearch/reference/5.6/setup-upgrade.html](https://www.elastic.co/guide/en/elasticsearch/reference/5.6/setup-upgrade.html) + +Be aware that if you add a new string value and want to be able to filter and search on this value from the Alerts UI, you **must** add a mapping for that type to +the appropriate Elasticsearch template. Below is more detail on how to choose the appropriate mapping type for your string value. + +## Type Mappings + +Type mappings have changed quite a bit from ES 2.x -> 5.x. Here is a brief rundown of the biggest changes. More detailed references from Elasticsearch +are provided in the [Type Mapping References](#type-mapping-references) section below. +* string fields replaced by text/keyword type +* strings have new default mappings as follows + + ``` + { + "type": "text", + "fields": { + "keyword": { + "type": "keyword", + "ignore_above": 256 + } + } + } + ``` + +* There is no longer a `_timestamp` field that you can set "enabled" on. This field now causes an exception on templates. +Replace with an application-created timestamp of "date" type. + +The semantics for string types have changed. In 2.x, you have the concept of index settings as either "analyzed" or "not_analyzed" which basically means "full text" and "keyword", respectively. +Analyzed text basically means the indexer will split the text using a text analyzer thus allowing you to search on substrings within the original text. "New York" is split and indexed as two buckets, + "New" and "York", so you can search or query for aggregate counts for those terms independently and will match against the individual terms "New" or "York." "Keyword" means that the original text + will not be split/analyzed during indexing and instead treated as a whole unit, i.e. "New" or "York" will not match in searches against the document containing "New York", but searching on "New York" + as the full city name will. In 5.x language instead of using the "index" setting, you now set the "type" to either "text" for full text, or "keyword" for keywords. + +Below is a table depicting the changes to how String types are now handled. + +<table> +<tr> + <th>sort, aggregate, or access values</th> + <th>ES 2.x</th> + <th>ES 5.x</th> + <th>Example</th> +</tr> +<tr> + <td>no</td> + <td> +<pre><code>"my_property" : { + "type": "string", + "index": "analyzed" +} +</code></pre> + </td> + <td> +<pre><code>"my_property" : { + "type": "text" +} +</code></pre> + Additional defaults: "index": "true", "fielddata": "false" + </td> + <td> + "New York" handled via in-mem search as "New" and "York" buckets. <strong>No</strong> aggregation or sort. + </td> +</tr> +<tr> + <td> + yes + </td> + <td> +<pre><code>"my_property": { + "type": "string", + "index": "analyzed" +} +</code></pre> + </td> + <td> +<pre><code>"my_property": { + "type": "text", + "fielddata": "true" +} +</code></pre> + </td> + <td> + "New York" handled via in-mem search as "New" and "York" buckets. <strong>Can</strong> aggregate and sort. + </td> +</tr> +<tr> + <td> + yes + </td> + <td> +<pre><code>"my_property": { + "type": "string", + "index": "not_analyzed" +} +</code></pre> + </td> + <td> +<pre><code>"my_property" : { + "type": "keyword" +} +</code></pre> + </td> + <td> + "New York" searchable as single value. <strong>Can</strong> aggregate and sort. A search for "New" or "York" will not match against the whole value. + </td> +</tr> +<tr> + <td> + yes + </td> + <td> +<pre><code>"my_property": { + "type": "string", + "index": "analyzed" +} +</code></pre> + </td> + <td> +<pre><code>"my_property": { + "type": "text", + "fields": { + "keyword": { + "type": "keyword", + "ignore_above": 256 + } + } +} +</code></pre> + </td> + <td> + "New York" searchable as single value or as text document, can aggregate and sort on the sub term "keyword." + </td> +</tr> +</table> + +If you want to set default string behavior for all strings for a given index and type, you can do so with a mapping similar to the following (replace ${your_type_here} accordingly): + +``` +# curl -XPUT 'http://${ES_HOST}:${ES_PORT}/_template/default_string_template' -d ' +{ + "template": "*", + "mappings" : { + "${your_type_here}": { + "dynamic_templates": [ + { + "strings": { + "match_mapping_type": "string", + "mapping": { + "type": "text" + } + } + } + ] + } + } +} +' +``` + +By specifying the "template" property with value "*" the template will apply to all indexes that have documents indexed of the specified type (${your_type_here}). This results in the following template. + +``` +# curl -XGET 'http://${ES_HOST}:${ES_PORT}/_template/default_string_template?pretty' +{ + "default_string_template" : { + "order" : 0, + "template" : "*", + "settings" : { }, + "mappings" : { + "${your_type_here}" : { + "dynamic_templates" : [ + { + "strings" : { + "match_mapping_type" : "string", + "mapping" : { + "type" : "text" + } + } + } + ] + } + }, + "aliases" : { } + } +} +``` + +Notes on other settings for types in ES +* doc_values + * on-disk data structure + * provides access for sorting, aggregation, and field values + * stores same values as _source, but in column-oriented fashion better for sorting and aggregating + * not supported on text fields + * enabled by default +* fielddata + * in-memory data structure + * provides access for sorting, aggregation, and field values + * primarily for text fields + * disabled by default because the heap space required can be large + + +##### Type Mapping References +* [https://www.elastic.co/guide/en/elasticsearch/reference/5.6/mapping.html](https://www.elastic.co/guide/en/elasticsearch/reference/5.6/mapping.html) +* [https://www.elastic.co/guide/en/elasticsearch/reference/5.6/breaking_50_mapping_changes.html](https://www.elastic.co/guide/en/elasticsearch/reference/5.6/breaking_50_mapping_changes.html) +* [https://www.elastic.co/blog/strings-are-dead-long-live-strings](https://www.elastic.co/blog/strings-are-dead-long-live-strings) + +## Using Metron with Elasticsearch 5.6.2 --- End diff -- All set
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