Related to #9049.
By default, the default value for `timestamp` is `now` which means the date the document was processed by the indexing chain.
You can now reject documents which not provide a `timestamp` value by setting `ignore_missing` to false (default to `true`):
```js
{
"tweet" : {
"_timestamp" : {
"enabled" : true,
"ignore_missing" : false
}
}
}
```
When you update the cluster to 1.5 or master, this index created with 1.4 we automatically migrate an index created with 1.4 to the 1.5 syntax.
Let say you have defined this in elasticsearch 1.4.x:
```js
DELETE test
PUT test
{
"settings": {
"number_of_shards": 1,
"number_of_replicas": 0
}
}
PUT test/type/_mapping
{
"type" : {
"_timestamp" : {
"enabled" : true,
"default" : null
}
}
}
```
After migration, the mapping become:
```js
{
"test": {
"mappings": {
"type": {
"_timestamp": {
"enabled": true,
"store": false,
"ignore_missing": false
},
"properties": {}
}
}
}
}
```
Closes#8882.
Storing `_timestamp` by default means that under the default configuration, you
would have all the information you need in order to reindex into a different
index.
Close#8139
Index process fails when having `_timestamp` enabled and `path` option is set.
It fails with a `TimestampParsingException[failed to parse timestamp [null]]` message.
Reproduction:
```
DELETE test
PUT test
{
"mappings": {
"test": {
"_timestamp" : {
"enabled" : "yes",
"path" : "post_date"
}
}
}
}
PUT test/test/1
{
"foo": "bar"
}
```
You can define a default value for when timestamp is not provided
within the index request or in the `_source` document.
By default, the default value is `now` which means the date the document was processed by the indexing chain.
You can disable that default value by setting `default` to `null`. It means that `timestamp` is mandatory:
```
{
"tweet" : {
"_timestamp" : {
"enabled" : true,
"default" : null
}
}
}
```
If you don't provide any timestamp value, indexation will fail.
You can also set the default value to any date respecting timestamp format:
```
{
"tweet" : {
"_timestamp" : {
"enabled" : true,
"format" : "YYYY-MM-dd",
"default" : "1970-01-01"
}
}
}
```
If you don't provide any timestamp value, indexation will fail.
Closes#4718.
Closes#7036.
David Pilato
Alban Perillat-Merceroz
Adrien Grand
hanneskaeufler
Konrad Feldmeier
Clinton Gormley