mirror of https://github.com/apache/druid.git
180 lines
9.3 KiB
Markdown
180 lines
9.3 KiB
Markdown
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---
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layout: doc_page
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---
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# Tutorial: Roll-up
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Druid can summarize raw data at ingestion time using a process we refer to as "roll-up". Roll-up is a first-level aggregation operation over a selected set of columns that reduces the size of stored segments.
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This tutorial will demonstrate the effects of roll-up on an example dataset.
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For this tutorial, we'll assume you've already downloaded Druid as described in
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the [single-machine quickstart](index.html) and have it running on your local machine.
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It will also be helpful to have finished [Tutorial: Loading a file](/docs/VERSION/tutorials/tutorial-batch.html) and [Tutorial: Querying data](/docs/VERSION/tutorials/tutorial-query.html).
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## Example data
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For this tutorial, we'll use a small sample of network flow event data, representing packet and byte counts for traffic from a source to a destination IP address that occurred within a particular second.
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```
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{"timestamp":"2018-01-01T01:01:35Z","srcIP":"1.1.1.1", "dstIP":"2.2.2.2","packets":20,"bytes":9024}
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{"timestamp":"2018-01-01T01:01:51Z","srcIP":"1.1.1.1", "dstIP":"2.2.2.2","packets":255,"bytes":21133}
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{"timestamp":"2018-01-01T01:01:59Z","srcIP":"1.1.1.1", "dstIP":"2.2.2.2","packets":11,"bytes":5780}
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{"timestamp":"2018-01-01T01:02:14Z","srcIP":"1.1.1.1", "dstIP":"2.2.2.2","packets":38,"bytes":6289}
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{"timestamp":"2018-01-01T01:02:29Z","srcIP":"1.1.1.1", "dstIP":"2.2.2.2","packets":377,"bytes":359971}
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{"timestamp":"2018-01-01T01:03:29Z","srcIP":"1.1.1.1", "dstIP":"2.2.2.2","packets":49,"bytes":10204}
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{"timestamp":"2018-01-02T21:33:14Z","srcIP":"7.7.7.7", "dstIP":"8.8.8.8","packets":38,"bytes":6289}
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{"timestamp":"2018-01-02T21:33:45Z","srcIP":"7.7.7.7", "dstIP":"8.8.8.8","packets":123,"bytes":93999}
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{"timestamp":"2018-01-02T21:35:45Z","srcIP":"7.7.7.7", "dstIP":"8.8.8.8","packets":12,"bytes":2818}
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```
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A file containing this sample input data is located at `quickstart/tutorial/rollup-data.json`.
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We'll ingest this data using the following ingestion task spec, located at `quickstart/tutorial/rollup-index.json`.
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```
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{
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"type" : "index",
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"spec" : {
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"dataSchema" : {
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"dataSource" : "rollup-tutorial",
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"parser" : {
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"type" : "string",
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"parseSpec" : {
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"format" : "json",
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"dimensionsSpec" : {
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"dimensions" : [
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"srcIP",
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"dstIP"
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]
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},
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"timestampSpec": {
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"column": "timestamp",
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"format": "iso"
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}
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}
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},
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"metricsSpec" : [
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{ "type" : "count", "name" : "count" },
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{ "type" : "longSum", "name" : "packets", "fieldName" : "packets" },
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{ "type" : "longSum", "name" : "bytes", "fieldName" : "bytes" }
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],
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"granularitySpec" : {
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"type" : "uniform",
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"segmentGranularity" : "week",
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"queryGranularity" : "minute",
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"intervals" : ["2018-01-01/2018-01-03"],
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"rollup" : true
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}
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},
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"ioConfig" : {
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"type" : "index",
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"firehose" : {
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"type" : "local",
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"baseDir" : "quickstart/tutorial",
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"filter" : "rollup-data.json"
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},
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"appendToExisting" : false
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},
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"tuningConfig" : {
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"type" : "index",
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"targetPartitionSize" : 5000000,
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"maxRowsInMemory" : 25000,
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"forceExtendableShardSpecs" : true
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}
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}
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}
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```
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Roll-up has been enabled by setting `"rollup" : true` in the `granularitySpec`.
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Note that we have `srcIP` and `dstIP` defined as dimensions, a longSum metric is defined for the `packets` and `bytes` columns, and the `queryGranularity` has been defined as `minute`.
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We will see how these definitions are used after we load this data.
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## Load the example data
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From the druid-${DRUIDVERSION} package root, run the following command:
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```
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bin/post-index-task --file quickstart/tutorial/rollup-index.json
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```
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After the script completes, we will query the data.
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## Query the example data
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Let's run `bin/dsql` and issue a `select * from "rollup-tutorial";` query to see what data was ingested.
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```
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$ bin/dsql
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Welcome to dsql, the command-line client for Druid SQL.
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Type "\h" for help.
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dsql> select * from "rollup-tutorial";
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┌──────────────────────────┬────────┬───────┬─────────┬─────────┬─────────┐
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│ __time │ bytes │ count │ dstIP │ packets │ srcIP │
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├──────────────────────────┼────────┼───────┼─────────┼─────────┼─────────┤
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│ 2018-01-01T01:01:00.000Z │ 35937 │ 3 │ 2.2.2.2 │ 286 │ 1.1.1.1 │
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│ 2018-01-01T01:02:00.000Z │ 366260 │ 2 │ 2.2.2.2 │ 415 │ 1.1.1.1 │
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│ 2018-01-01T01:03:00.000Z │ 10204 │ 1 │ 2.2.2.2 │ 49 │ 1.1.1.1 │
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│ 2018-01-02T21:33:00.000Z │ 100288 │ 2 │ 8.8.8.8 │ 161 │ 7.7.7.7 │
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│ 2018-01-02T21:35:00.000Z │ 2818 │ 1 │ 8.8.8.8 │ 12 │ 7.7.7.7 │
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└──────────────────────────┴────────┴───────┴─────────┴─────────┴─────────┘
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Retrieved 5 rows in 1.18s.
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dsql>
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```
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Let's look at the three events in the original input data that occurred during `2018-01-01T01:01`:
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```
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{"timestamp":"2018-01-01T01:01:35Z","srcIP":"1.1.1.1", "dstIP":"2.2.2.2","packets":20,"bytes":9024}
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{"timestamp":"2018-01-01T01:01:51Z","srcIP":"1.1.1.1", "dstIP":"2.2.2.2","packets":255,"bytes":21133}
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{"timestamp":"2018-01-01T01:01:59Z","srcIP":"1.1.1.1", "dstIP":"2.2.2.2","packets":11,"bytes":5780}
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```
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These three rows have been "rolled up" into the following row:
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```
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┌──────────────────────────┬────────┬───────┬─────────┬─────────┬─────────┐
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│ __time │ bytes │ count │ dstIP │ packets │ srcIP │
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├──────────────────────────┼────────┼───────┼─────────┼─────────┼─────────┤
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│ 2018-01-01T01:01:00.000Z │ 35937 │ 3 │ 2.2.2.2 │ 286 │ 1.1.1.1 │
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└──────────────────────────┴────────┴───────┴─────────┴─────────┴─────────┘
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```
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The input rows have been grouped by the timestamp and dimension columns `{timestamp, srcIP, dstIP}` with sum aggregations on the metric columns `packets` and `bytes`.
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Before the grouping occurs, the timestamps of the original input data are bucketed/floored by minute, due to the `"queryGranularity":"minute"` setting in the ingestion spec.
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Likewise, these two events that occurred during `2018-01-01T01:02` have been rolled up:
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```
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{"timestamp":"2018-01-01T01:02:14Z","srcIP":"1.1.1.1", "dstIP":"2.2.2.2","packets":38,"bytes":6289}
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{"timestamp":"2018-01-01T01:02:29Z","srcIP":"1.1.1.1", "dstIP":"2.2.2.2","packets":377,"bytes":359971}
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```
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```
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┌──────────────────────────┬────────┬───────┬─────────┬─────────┬─────────┐
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│ __time │ bytes │ count │ dstIP │ packets │ srcIP │
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├──────────────────────────┼────────┼───────┼─────────┼─────────┼─────────┤
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│ 2018-01-01T01:02:00.000Z │ 366260 │ 2 │ 2.2.2.2 │ 415 │ 1.1.1.1 │
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└──────────────────────────┴────────┴───────┴─────────┴─────────┴─────────┘
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```
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For the last event recording traffic between 1.1.1.1 and 2.2.2.2, no roll-up took place, because this was the only event that occurred during `2018-01-01T01:03`:
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```
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{"timestamp":"2018-01-01T01:03:29Z","srcIP":"1.1.1.1", "dstIP":"2.2.2.2","packets":49,"bytes":10204}
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```
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```
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┌──────────────────────────┬────────┬───────┬─────────┬─────────┬─────────┐
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│ __time │ bytes │ count │ dstIP │ packets │ srcIP │
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├──────────────────────────┼────────┼───────┼─────────┼─────────┼─────────┤
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│ 2018-01-01T01:03:00.000Z │ 10204 │ 1 │ 2.2.2.2 │ 49 │ 1.1.1.1 │
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└──────────────────────────┴────────┴───────┴─────────┴─────────┴─────────┘
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```
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Note that the `count` metric shows how many rows in the original input data contributed to the final "rolled up" row.
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