diff --git a/docs/java-rest/high-level/rollup/put_job.asciidoc b/docs/java-rest/high-level/rollup/put_job.asciidoc index 5e763616919..ff80bca9757 100644 --- a/docs/java-rest/high-level/rollup/put_job.asciidoc +++ b/docs/java-rest/high-level/rollup/put_job.asciidoc @@ -21,7 +21,7 @@ include-tagged::{doc-tests}/RollupDocumentationIT.java[x-pack-rollup-put-rollup- ==== Rollup Job Configuration The `RollupJobConfig` object contains all the details about the rollup job -configuration. See {ref}/rollup-job-config.html[Rollup configuration] to learn more +configuration. See {ref}/rollup-put-job.html[create rollup job API] to learn more about the various configuration settings. A `RollupJobConfig` requires the following arguments: @@ -45,7 +45,7 @@ include-tagged::{doc-tests}/RollupDocumentationIT.java[x-pack-rollup-put-rollup- The grouping configuration of the Rollup job is defined in the `RollupJobConfig` using a `GroupConfig` instance. `GroupConfig` reflects all the configuration -settings that can be defined using the REST API. See {ref}/rollup-job-config.html#rollup-groups-config[Grouping Config] +settings that can be defined using the REST API. See {ref}/rollup-put-job.html#rollup-groups-config[Grouping config] to learn more about these settings. Using the REST API, we could define this grouping configuration: @@ -89,7 +89,7 @@ include-tagged::{doc-tests}/RollupDocumentationIT.java[x-pack-rollup-put-rollup- After defining which groups should be generated for the data, you next configure which metrics should be collected. The list of metrics is defined in the `RollupJobConfig` using a `List` instance. `MetricConfig` reflects all the configuration -settings that can be defined using the REST API. See {ref}/rollup-job-config.html#rollup-metrics-config[Metrics Config] +settings that can be defined using the REST API. See {ref}/rollup-put-job.html#rollup-metrics-config[Metrics config] to learn more about these settings. Using the REST API, we could define this metrics configuration: diff --git a/docs/reference/aggregations/bucket/datehistogram-aggregation.asciidoc b/docs/reference/aggregations/bucket/datehistogram-aggregation.asciidoc index 62cd850a276..0e8e0e144b1 100644 --- a/docs/reference/aggregations/bucket/datehistogram-aggregation.asciidoc +++ b/docs/reference/aggregations/bucket/datehistogram-aggregation.asciidoc @@ -1,5 +1,5 @@ [[search-aggregations-bucket-datehistogram-aggregation]] -=== Date Histogram Aggregation +=== Date histogram aggregation This multi-bucket aggregation is similar to the normal <>, but it can @@ -10,7 +10,8 @@ that here the interval can be specified using date/time expressions. Time-based data requires special support because time-based intervals are not always a fixed length. -==== Calendar and Fixed intervals +[[calendar_and_fixed_intervals]] +==== Calendar and fixed intervals When configuring a date histogram aggregation, the interval can be specified in two manners: calendar-aware time intervals, and fixed time intervals. @@ -42,7 +43,8 @@ are clear to the user immediately and there is no ambiguity. The old `interval` will be removed in the future. ================================== -===== Calendar Intervals +[[calendar_intervals]] +===== Calendar intervals Calendar-aware intervals are configured with the `calendar_interval` parameter. Calendar intervals can only be specified in "singular" quantities of the unit @@ -100,7 +102,8 @@ One year (1y) is the interval between the start day of the month and time of day and the same day of the month and time of day the following year in the specified timezone, so that the date and time are the same at the start and end. + -===== Calendar Interval Examples +[[calendar_interval_examples]] +===== Calendar interval examples As an example, here is an aggregation requesting bucket intervals of a month in calendar time: [source,console] @@ -157,7 +160,8 @@ POST /sales/_search?size=0 -------------------------------------------------- // NOTCONSOLE -===== Fixed Intervals +[[fixed_intervals]] +===== Fixed intervals Fixed intervals are configured with the `fixed_interval` parameter. @@ -192,7 +196,8 @@ All days begin at the earliest possible time, which is usually 00:00:00 Defined as 24 hours (86,400,000 milliseconds) -===== Fixed Interval Examples +[[fixed_interval_examples]] +===== Fixed interval examples If we try to recreate the "month" `calendar_interval` from earlier, we can approximate that with 30 fixed days: diff --git a/docs/reference/redirects.asciidoc b/docs/reference/redirects.asciidoc index 3f664682d45..41de4915f7f 100644 --- a/docs/reference/redirects.asciidoc +++ b/docs/reference/redirects.asciidoc @@ -1015,3 +1015,8 @@ See <>. === How security works See <>. + +[role="exclude",id="rollup-job-config"] +=== Rollup job configuration + +See <>. diff --git a/docs/reference/rollup/apis/put-job.asciidoc b/docs/reference/rollup/apis/put-job.asciidoc index 1816edc8038..54203dec5bc 100644 --- a/docs/reference/rollup/apis/put-job.asciidoc +++ b/docs/reference/rollup/apis/put-job.asciidoc @@ -26,6 +26,14 @@ experimental[] [[rollup-put-job-api-desc]] ==== {api-description-title} +The {rollup-job} configuration contains all the details about how the job should +run, when it indexes documents, and what future queries will be able to execute +against the rollup index. + +There are three main sections to the job configuration: the logistical details +about the job (cron schedule, etc), the fields that are used for grouping, and +what metrics to collect for each group. + Jobs are created in a `STOPPED` state. You can start them with the <>. @@ -33,42 +41,183 @@ Jobs are created in a `STOPPED` state. You can start them with the ==== {api-path-parms-title} ``:: - (Required, string) Identifier for the {rollup-job}. + (Required, string) Identifier for the {rollup-job}. This can be any + alphanumeric string and uniquely identifies the data that is associated with + the {rollup-job}. The ID is persistent; it is stored with the rolled up data. + If you create a job, let it run for a while, then delete the job, the data + that the job rolled up is still be associated with this job ID. You cannot + create a new job with the same ID since that could lead to problems with + mismatched job configurations. [[rollup-put-job-api-request-body]] ==== {api-request-body-title} `cron`:: - (Required, string) A cron string which defines when the {rollup-job} should be executed. + (Required, string) A cron string which defines the intervals when the + {rollup-job} should be executed. When the interval triggers, the indexer + attempts to rollup the data in the index pattern. The cron pattern is + unrelated to the time interval of the data being rolled up. For example, you + may wish to create hourly rollups of your document but to only run the indexer + on a daily basis at midnight, as defined by the cron. The cron pattern is + defined just like a {watcher} cron schedule. +[[rollup-groups-config]] `groups`:: - (Required, object) Defines the grouping fields that are defined for this - {rollup-job}. See <>. + (Required, object) Defines the grouping fields and aggregations that are + defined for this {rollup-job}. These fields will then be available later for + aggregating into buckets. ++ +-- +These aggs and fields can be used in any combination. Think of the `groups` +configuration as defining a set of tools that can later be used in aggregations +to partition the data. Unlike raw data, we have to think ahead to which fields +and aggregations might be used. Rollups provide enough flexibility that you +simply need to determine _which_ fields are needed, not _in what order_ they are +needed. + +There are three types of groupings currently available: +-- + +`date_histogram`::: + (Required, object) A date histogram group aggregates a `date` field into + time-based buckets. This group is *mandatory*; you currently cannot rollup + documents without a timestamp and a `date_histogram` group. The + `date_histogram` group has several parameters: + +`field`:::: + (Required, string) The date field that is to be rolled up. + +`calendar_interval` or `fixed_interval`:::: + (Required, <>) The interval of time buckets to be + generated when rolling up. For example, `60m` produces 60 minute (hourly) + rollups. This follows standard time formatting syntax as used elsewhere in + {es}. The interval defines the _minimum_ interval that can be aggregated only. + If hourly (`60m`) intervals are configured, <> + can execute aggregations with 60m or greater (weekly, monthly, etc) intervals. + So define the interval as the smallest unit that you wish to later query. For + more information about the difference between calendar and fixed time + intervals, see <>. ++ +-- +NOTE: Smaller, more granular intervals take up proportionally more space. + +-- + +`delay`:::: + (Optional,<>) How long to wait before rolling up new + documents. By default, the indexer attempts to roll up all data that is + available. However, it is not uncommon for data to arrive out of order, + sometimes even a few days late. The indexer is unable to deal with data that + arrives after a time-span has been rolled up. That is to say, there is no + provision to update already-existing rollups. ++ +-- +Instead, you should specify a `delay` that matches the longest period of time +you expect out-of-order data to arrive. For example, a `delay` of `1d` +instructs the indexer to roll up documents up to `now - 1d`, which provides +a day of buffer time for out-of-order documents to arrive. +-- + +`time_zone`:::: + (Optional, string) Defines what time_zone the rollup documents are stored as. + Unlike raw data, which can shift timezones on the fly, rolled documents have + to be stored with a specific timezone. By default, rollup documents are stored + in `UTC`. + +`terms`::: + (Optional, object) The terms group can be used on `keyword` or numeric fields + to allow bucketing via the `terms` aggregation at a later point. The indexer + enumerates and stores _all_ values of a field for each time-period. This can + be potentially costly for high-cardinality groups such as IP addresses, + especially if the time-bucket is particularly sparse. ++ +-- +TIP: While it is unlikely that a rollup will ever be larger in size than the raw +data, defining `terms` groups on multiple high-cardinality fields can +effectively reduce the compression of a rollup to a large extent. You should be +judicious which high-cardinality fields are included for that reason. + +The `terms` group has a single parameter: +-- + +`fields`:::: + (Required, string) The set of fields that you wish to collect terms for. This + array can contain fields that are both `keyword` and numerics. Order does not + matter. + +`histogram`::: + (Optional, object) The histogram group aggregates one or more numeric fields + into numeric histogram intervals. ++ +-- +The `histogram` group has a two parameters: +-- + +`fields`:::: + (Required, array) The set of fields that you wish to build histograms for. All fields + specified must be some kind of numeric. Order does not matter. + +`interval`:::: + (Required, integer) The interval of histogram buckets to be generated when + rolling up. For example, a value of `5` creates buckets that are five units + wide (`0-5`, `5-10`, etc). Note that only one interval can be specified in the + `histogram` group, meaning that all fields being grouped via the histogram + must share the same interval. `index_pattern`:: (Required, string) The index or index pattern to roll up. Supports - wildcard-style patterns (`logstash-*`). + wildcard-style patterns (`logstash-*`). The job will + attempt to rollup the entire index or index-pattern. ++ +-- +NOTE: The `index_pattern` cannot be a pattern that would also match the +destination `rollup_index`. For example, the pattern `foo-*` would match the +rollup index `foo-rollup`. This situation would cause problems because the +{rollup-job} would attempt to rollup its own data at runtime. If you attempt to +configure a pattern that matches the `rollup_index`, an exception occurs to +prevent this behavior. +-- + +[[rollup-metrics-config]] `metrics`:: - (Optional, object) Defines the metrics to collect for each grouping tuple. See - <>. + (Optional, object) Defines the metrics to collect for each grouping tuple. + By default, only the doc_counts are collected for each group. To make rollup + useful, you will often add metrics like averages, mins, maxes, etc. Metrics + are defined on a per-field basis and for each field you configure which metric + should be collected. ++ +-- +The `metrics` configuration accepts an array of objects, where each object has +two parameters: +-- + +`field`::: + (Required, string) The field to collect metrics for. This must be a numeric + of some kind. + +`metrics`::: + (Required, array) An array of metrics to collect for the field. At least one + metric must be configured. Acceptable metrics are `min`,`max`,`sum`,`avg`, and + `value_count`. `page_size`:: (Required, integer) The number of bucket results that are processed on each iteration of the rollup indexer. A larger value tends to execute faster, but - requires more memory during processing. + requires more memory during processing. This value has no effect on how the + data is rolled up; it is merely used for tweaking the speed or memory cost of + the indexer. `rollup_index`:: (Required, string) The index that contains the rollup results. The index can - be shared with other {rollup-jobs}. - -For more details about the job configuration, see <>. + be shared with other {rollup-jobs}. The data is stored so that it doesn't + interfere with unrelated jobs. [[rollup-put-job-api-example]] ==== {api-example-title} -The following example creates a {rollup-job} named "sensor", targeting the -"sensor-*" index pattern: +The following example creates a {rollup-job} named `sensor`, targeting the +`sensor-*` index pattern: [source,console] -------------------------------------------------- @@ -78,7 +227,7 @@ PUT _rollup/job/sensor "rollup_index": "sensor_rollup", "cron": "*/30 * * * * ?", "page_size" :1000, - "groups" : { + "groups" : { <1> "date_histogram": { "field": "timestamp", "fixed_interval": "1h", @@ -88,7 +237,7 @@ PUT _rollup/job/sensor "fields": ["node"] } }, - "metrics": [ + "metrics": [ <2> { "field": "temperature", "metrics": ["min", "max", "sum"] @@ -101,6 +250,11 @@ PUT _rollup/job/sensor } -------------------------------------------------- // TEST[setup:sensor_index] +<1> This configuration enables date histograms to be used on the `timestamp` +field and `terms` aggregations to be used on the `node` field. +<2> This configuration defines metrics over two fields: `temperature` and +`voltage`. For the `temperature` field, we are collecting the min, max, and +sum of the temperature. For `voltage`, we are collecting the average. When the job is created, you receive the following results: @@ -109,4 +263,4 @@ When the job is created, you receive the following results: { "acknowledged": true } ----- \ No newline at end of file +---- diff --git a/docs/reference/rollup/apis/rollup-job-config.asciidoc b/docs/reference/rollup/apis/rollup-job-config.asciidoc deleted file mode 100644 index e0ca2b73320..00000000000 --- a/docs/reference/rollup/apis/rollup-job-config.asciidoc +++ /dev/null @@ -1,279 +0,0 @@ -[role="xpack"] -[testenv="basic"] -[[rollup-job-config]] -=== Rollup job configuration - -experimental[] - -The Rollup Job Configuration contains all the details about how the rollup job should run, when it indexes documents, -and what future queries will be able to execute against the rollup index. - -There are three main sections to the Job Configuration; the logistical details about the job (cron schedule, etc), what fields -should be grouped on, and what metrics to collect for each group. - -A full job configuration might look like this: - -[source,console] --------------------------------------------------- -PUT _rollup/job/sensor -{ - "index_pattern": "sensor-*", - "rollup_index": "sensor_rollup", - "cron": "*/30 * * * * ?", - "page_size" :1000, - "groups" : { - "date_histogram": { - "field": "timestamp", - "fixed_interval": "60m", - "delay": "7d" - }, - "terms": { - "fields": ["hostname", "datacenter"] - }, - "histogram": { - "fields": ["load", "net_in", "net_out"], - "interval": 5 - } - }, - "metrics": [ - { - "field": "temperature", - "metrics": ["min", "max", "sum"] - }, - { - "field": "voltage", - "metrics": ["avg"] - } - ] -} --------------------------------------------------- -// TEST[setup:sensor_index] - -==== Logistical Details - -In the above example, there are several pieces of logistical configuration for the job itself. - -`{job_id}` (required):: - (string) In the endpoint URL, you specify the name of the job (`sensor` in the above example). This can be any alphanumeric string, - and uniquely identifies the data that is associated with the rollup job. The ID is persistent, in that it is stored with the rolled - up data. So if you create a job, let it run for a while, then delete the job... the data that the job rolled up will still be - associated with this job ID. You will be unable to create a new job with the same ID, as that could lead to problems with mismatched - job configurations - -`index_pattern` (required):: - (string) The index, or index pattern, that you wish to rollup. Supports wildcard-style patterns (`logstash-*`). The job will - attempt to rollup the entire index or index-pattern. Once the "backfill" is finished, it will periodically (as defined by the cron) - look for new data and roll that up too. - -`rollup_index` (required):: - (string) The index that you wish to store rollup results into. All the rollup data that is generated by the job will be - stored in this index. When searching the rollup data, this index will be used in the <> endpoint's URL. - The rollup index can be shared with other rollup jobs. The data is stored so that it doesn't interfere with unrelated jobs. - -`cron` (required):: - (string) A cron string which defines when the rollup job should be executed. The cron string defines an interval of when to run - the job's indexer. When the interval triggers, the indexer will attempt to rollup the data in the index pattern. The cron pattern - is unrelated to the time interval of the data being rolled up. For example, you may wish to create hourly rollups of your document (as - defined in the <>) but to only run the indexer on a daily basis at midnight, as defined by the cron. - The cron pattern is defined just like Watcher's Cron Schedule. - -`page_size` (required):: - (int) The number of bucket results that should be processed on each iteration of the rollup indexer. A larger value - will tend to execute faster, but will require more memory during processing. This has no effect on how the data is rolled up, it is - merely used for tweaking the speed/memory cost of the indexer. - -[NOTE] -The `index_pattern` cannot be a pattern that would also match the destination `rollup_index`. E.g. the pattern -`"foo-*"` would match the rollup index `"foo-rollup"`. This causes problems because the rollup job would attempt -to rollup it's own data at runtime. If you attempt to configure a pattern that matches the `rollup_index`, an exception -will be thrown to prevent this behavior. - -[[rollup-groups-config]] -==== Grouping Config - -The `groups` section of the configuration is where you decide which fields should be grouped on, and with what aggregations. These -fields will then be available later for aggregating into buckets. For example, this configuration: - -[source,js] --------------------------------------------------- -"groups" : { - "date_histogram": { - "field": "timestamp", - "fixed_interval": "60m", - "delay": "7d" - }, - "terms": { - "fields": ["hostname", "datacenter"] - }, - "histogram": { - "fields": ["load", "net_in", "net_out"], - "interval": 5 - } -} --------------------------------------------------- -// NOTCONSOLE - -Allows `date_histogram`'s to be used on the `"timestamp"` field, `terms` aggregations to be used on the `"hostname"` and `"datacenter"` -fields, and `histograms` to be used on any of `"load"`, `"net_in"`, `"net_out"` fields. - -Importantly, these aggs/fields can be used in any combination. Think of the `groups` configuration as defining a set of tools that can -later be used in aggregations to partition the data. Unlike raw data, we have to think ahead to which fields and aggregations might be used. -But Rollups provide enough flexibility that you simply need to determine _which_ fields are needed, not _in what order_ they are needed. - -There are three types of groupings currently available: - -===== Date Histogram - -A `date_histogram` group aggregates a `date` field into time-based buckets. The `date_histogram` group is *mandatory* -- you currently -cannot rollup documents without a timestamp and a `date_histogram` group. - -The `date_histogram` group has several parameters: - -`field` (required):: - The date field that is to be rolled up. - -`interval` (required):: - The interval of time buckets to be generated when rolling up. E.g. `"60m"` will produce 60 minute (hourly) rollups. This follows standard time formatting - syntax as used elsewhere in Elasticsearch. The `interval` defines the _minimum_ interval that can be aggregated only. If hourly (`"60m"`) - intervals are configured, <> can execute aggregations with 60m or greater (weekly, monthly, etc) intervals. - So define the interval as the smallest unit that you wish to later query. - - Note: smaller, more granular intervals take up proportionally more space. - -`delay`:: - How long to wait before rolling up new documents. By default, the indexer attempts to roll up all data that is available. However, it - is not uncommon for data to arrive out of order, sometimes even a few days late. The indexer is unable to deal with data that arrives - after a time-span has been rolled up (e.g. there is no provision to update already-existing rollups). - - Instead, you should specify a `delay` that matches the longest period of time you expect out-of-order data to arrive. E.g. a `delay` of - `"1d"` will instruct the indexer to roll up documents up to `"now - 1d"`, which provides a day of buffer time for out-of-order documents - to arrive. - -`time_zone`:: - Defines what time_zone the rollup documents are stored as. Unlike raw data, which can shift timezones on the fly, rolled documents have - to be stored with a specific timezone. By default, rollup documents are stored in `UTC`, but this can be changed with the `time_zone` - parameter. - -.Calendar vs Fixed time intervals -********************************** -Elasticsearch understands both "calendar" and "fixed" time intervals. Fixed time intervals are fairly easy to understand; -`"60s"` means sixty seconds. But what does `"1M` mean? One month of time depends on which month we are talking about, -some months are longer or shorter than others. This is an example of "calendar" time, and the duration of that unit -depends on context. Calendar units are also affected by leap-seconds, leap-years, etc. - -This is important because the buckets generated by Rollup will be in either calendar or fixed intervals, and will limit -how you can query them later (see <>. - -We recommend sticking with "fixed" time intervals, since they are easier to understand and are more flexible at query -time. It will introduce some drift in your data during leap-events, and you will have to think about months in a fixed -quantity (30 days) instead of the actual calendar length... but it is often easier than dealing with calendar units -at query time. - -Multiples of units are always "fixed" (e.g. `"2h"` is always the fixed quantity `7200` seconds. Single units can be -fixed or calendar depending on the unit: - -[options="header"] -|======= -|Unit |Calendar |Fixed -|millisecond |NA |`1ms`, `10ms`, etc -|second |NA |`1s`, `10s`, etc -|minute |`1m` |`2m`, `10m`, etc -|hour |`1h` |`2h`, `10h`, etc -|day |`1d` |`2d`, `10d`, etc -|week |`1w` |NA -|month |`1M` |NA -|quarter |`1q` |NA -|year |`1y` |NA -|======= - -For some units where there are both fixed and calendar, you may need to express the quantity in terms of the next -smaller unit. For example, if you want a fixed day (not a calendar day), you should specify `24h` instead of `1d`. -Similarly, if you want fixed hours, specify `60m` instead of `1h`. This is because the single quantity entails -calendar time, and limits you to querying by calendar time in the future. - - -********************************** - -===== Terms - -The `terms` group can be used on `keyword` or numeric fields, to allow bucketing via the `terms` aggregation at a later point. The `terms` -group is optional. If defined, the indexer will enumerate and store _all_ values of a field for each time-period. This can be potentially -costly for high-cardinality groups such as IP addresses, especially if the time-bucket is particularly sparse. - -While it is unlikely that a rollup will ever be larger in size than the raw data, defining `terms` groups on multiple high-cardinality fields -can effectively reduce the compression of a rollup to a large extent. You should be judicious which high-cardinality fields are included -for that reason. - -The `terms` group has a single parameter: - -`fields` (required):: - The set of fields that you wish to collect terms for. This array can contain fields that are both `keyword` and numerics. Order - does not matter - - -===== Histogram - -The `histogram` group aggregates one or more numeric fields into numeric histogram intervals. This group is optional - - -The `histogram` group has a two parameters: - -`fields` (required):: - The set of fields that you wish to build histograms for. All fields specified must be some kind of numeric. Order does not matter - -`interval` (required):: - The interval of histogram buckets to be generated when rolling up. E.g. `5` will create buckets that are five units wide - (`0-5`, `5-10`, etc). Note that only one interval can be specified in the `histogram` group, meaning that all fields being grouped via - the histogram must share the same interval. - -[[rollup-metrics-config]] -==== Metrics Config - -After defining which groups should be generated for the data, you next configure which metrics should be collected. By default, only -the doc_counts are collected for each group. To make rollup useful, you will often add metrics like averages, mins, maxes, etc. - -Metrics are defined on a per-field basis, and for each field you configure which metric should be collected. For example: - -[source,js] --------------------------------------------------- -"metrics": [ - { - "field": "temperature", - "metrics": ["min", "max", "sum"] - }, - { - "field": "voltage", - "metrics": ["avg"] - } -] --------------------------------------------------- -// NOTCONSOLE - -This configuration defines metrics over two fields, `"temperature` and `"voltage"`. For the `"temperature"` field, we are collecting -the min, max and sum of the temperature. For `"voltage"`, we are collecting the average. These metrics are collected in a way that makes -them compatible with any combination of defined groups. - -The `metrics` configuration accepts an array of objects, where each object has two parameters: - -`field` (required):: - The field to collect metrics for. This must be a numeric of some kind - -`metrics` (required):: - An array of metrics to collect for the field. At least one metric must be configured. Acceptable metrics are min/max/sum/avg/value_count. - - - -.Averages aren't composable?! -********************************** -If you've worked with rollups before, you may be cautious around averages. If an average is saved for a 10 minute -interval, it usually isn't useful for larger intervals. You cannot average six 10-minute averages to find a -hourly average (average of averages is not equal to the total average). - -For this reason, other systems tend to either omit the ability to average, or store the average at multiple intervals -to support more flexible querying. - -Instead, the Rollup feature saves the `count` and `sum` for the defined time interval. This allows us to reconstruct -the average at any interval greater-than or equal to the defined interval. This gives maximum flexibility for -minimal storage costs... and you don't have to worry about average accuracies (no average of averages here!) -********************************** - diff --git a/docs/reference/rollup/rollup-api.asciidoc b/docs/reference/rollup/rollup-api.asciidoc index c156265c2ff..9e56c5f1584 100644 --- a/docs/reference/rollup/rollup-api.asciidoc +++ b/docs/reference/rollup/rollup-api.asciidoc @@ -10,7 +10,6 @@ * <> or <> * <> or <> * <> -* <> [float] [[rollup-data-endpoint]] @@ -32,6 +31,5 @@ include::apis/get-job.asciidoc[] include::apis/rollup-caps.asciidoc[] include::apis/rollup-index-caps.asciidoc[] include::apis/rollup-search.asciidoc[] -include::apis/rollup-job-config.asciidoc[] include::apis/start-job.asciidoc[] include::apis/stop-job.asciidoc[] \ No newline at end of file diff --git a/docs/reference/rollup/rollup-getting-started.asciidoc b/docs/reference/rollup/rollup-getting-started.asciidoc index 3b57e968a9e..740a921713d 100644 --- a/docs/reference/rollup/rollup-getting-started.asciidoc +++ b/docs/reference/rollup/rollup-getting-started.asciidoc @@ -72,12 +72,11 @@ seconds worth of data that was indexed into the `sensor-*` indices. If instead the cron was configured to run once a day at midnight, the job would process the last 24 hours worth of data. The choice is largely preference, based on how "realtime" you want the rollups, and if you wish to process continuously or move it to off-peak hours. -Next, we define a set of `groups` and `metrics`. The metrics are fairly straightforward: we want to save the min/max/sum of the `temperature` -field, and the average of the `voltage` field. - -The groups are a little more interesting. Essentially, we are defining the dimensions that we wish to pivot on at a later date when -querying the data. The grouping in this job allows us to use date_histograms aggregations on the `timestamp` field, rolled up at hourly intervals. -It also allows us to run terms aggregations on the `node` field. +Next, we define a set of `groups`. Essentially, we are defining the dimensions +that we wish to pivot on at a later date when querying the data. The grouping in +this job allows us to use `date_histogram` aggregations on the `timestamp` field, +rolled up at hourly intervals. It also allows us to run terms aggregations on +the `node` field. .Date histogram interval vs cron schedule ********************************** @@ -93,8 +92,31 @@ simply go back to sleep. But there's nothing wrong with it either, the job will ********************************** -For more details about the job syntax, see <>. +After defining which groups should be generated for the data, you next configure +which metrics should be collected. By default, only the `doc_counts` are +collected for each group. To make rollup useful, you will often add metrics +like averages, mins, maxes, etc. In this example, the metrics are fairly +straightforward: we want to save the min/max/sum of the `temperature` +field, and the average of the `voltage` field. +.Averages aren't composable?! +********************************** +If you've worked with rollups before, you may be cautious around averages. If an +average is saved for a 10 minute interval, it usually isn't useful for larger +intervals. You cannot average six 10-minute averages to find a hourly average; +the average of averages is not equal to the total average. + +For this reason, other systems tend to either omit the ability to average or +store the average at multiple intervals to support more flexible querying. + +Instead, the {rollup-features} save the `count` and `sum` for the defined time +interval. This allows us to reconstruct the average at any interval greater-than +or equal to the defined interval. This gives maximum flexibility for minimal +storage costs... and you don't have to worry about average accuracies (no +average of averages here!) +********************************** + +For more details about the job syntax, see <>. After you execute the above command and create the job, you'll receive the following response: diff --git a/docs/reference/rollup/understanding-groups.asciidoc b/docs/reference/rollup/understanding-groups.asciidoc index eb1b47e8a16..8d0aadb9778 100644 --- a/docs/reference/rollup/understanding-groups.asciidoc +++ b/docs/reference/rollup/understanding-groups.asciidoc @@ -119,7 +119,54 @@ Rollup Search to execute: Ultimately, when configuring `groups` for a job, think in terms of how you might wish to partition data in a query at a future date... then include those in the config. Because Rollup Search allows any order or combination of the grouped fields, you just need to decide -if a field is useful for aggregating later, and how you might wish to use it (terms, histogram, etc) +if a field is useful for aggregating later, and how you might wish to use it (terms, histogram, etc). + +[[rollup-understanding-group-intervals]] +==== Calendar vs fixed time intervals + +Each rollup-job must have a date histogram group with a defined interval. {es} +understands both +<>. Fixed time +intervals are fairly easy to understand; `60s` means sixty seconds. But what +does `1M` mean? One month of time depends on which month we are talking about, +some months are longer or shorter than others. This is an example of calendar +time and the duration of that unit depends on context. Calendar units are also +affected by leap-seconds, leap-years, etc. + +This is important because the buckets generated by rollup are in either calendar +or fixed intervals and this limits how you can query them later. See +<>. + +We recommend sticking with fixed time intervals, since they are easier to +understand and are more flexible at query time. It will introduce some drift in +your data during leap-events and you will have to think about months in a fixed +quantity (30 days) instead of the actual calendar length. However, it is often +easier than dealing with calendar units at query time. + +Multiples of units are always "fixed". For example, `2h` is always the fixed +quantity `7200` seconds. Single units can be fixed or calendar depending on the +unit: + +[options="header"] +|======= +|Unit |Calendar |Fixed +|millisecond |NA |`1ms`, `10ms`, etc +|second |NA |`1s`, `10s`, etc +|minute |`1m` |`2m`, `10m`, etc +|hour |`1h` |`2h`, `10h`, etc +|day |`1d` |`2d`, `10d`, etc +|week |`1w` |NA +|month |`1M` |NA +|quarter |`1q` |NA +|year |`1y` |NA +|======= + +For some units where there are both fixed and calendar, you may need to express +the quantity in terms of the next smaller unit. For example, if you want a fixed +day (not a calendar day), you should specify `24h` instead of `1d`. Similarly, +if you want fixed hours, specify `60m` instead of `1h`. This is because the +single quantity entails calendar time, and limits you to querying by calendar +time in the future. ==== Grouping limitations with heterogeneous indices