hevansDev commented on code in PR #16908: URL: https://github.com/apache/druid/pull/16908#discussion_r1736908217
########## docs/tutorials/tutorial-transform-spec.md: ########## @@ -0,0 +1,148 @@ +--- +id: tutorial-transform-spec +title: Transform input data +sidebar_label: Transform input data +--- + +<!-- + ~ Licensed to the Apache Software Foundation (ASF) under one + ~ or more contributor license agreements. See the NOTICE file + ~ distributed with this work for additional information + ~ regarding copyright ownership. The ASF licenses this file + ~ to you under the Apache License, Version 2.0 (the + ~ "License"); you may not use this file except in compliance + ~ with the License. You may obtain a copy of the License at + ~ + ~ http://www.apache.org/licenses/LICENSE-2.0 + ~ + ~ Unless required by applicable law or agreed to in writing, + ~ software distributed under the License is distributed on an + ~ "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + ~ KIND, either express or implied. See the License for the + ~ specific language governing permissions and limitations + ~ under the License. + --> + + +This tutorial will demonstrate how to use transform specs to filter and transform input data during ingestion. + +For this tutorial, we'll assume you've already downloaded Apache Druid as described in +the [single-machine quickstart](index.md) and have it running on your local machine. + +It will also be helpful to have finished [Load a file](../tutorials/tutorial-batch.md) and [Query data](../tutorials/tutorial-query.md) tutorials. + +## Sample data + +We've included sample data for this tutorial at `quickstart/tutorial/transform-data.json`, reproduced here for convenience: + +```json +{"timestamp": "2018-01-01T07:01:35Z","animal": "octopus","location": 1,"number": 100} +{"timestamp": "2018-01-01T05:01:35Z","animal": "mongoose","location": 2,"number": 200} +{"timestamp": "2018-01-01T06:01:35Z","animal": "snake","location": 3,"number": 300} +{"timestamp": "2018-01-01T01:01:35Z","animal": "lion","location": 4,"number": 300} +``` + +## Load data with transform specs + +We will ingest the sample data using the following spec, which demonstrates the use of transform specs: + +```json +{ + "type" : "index_parallel", + "spec" : { + "dataSchema" : { + "dataSource" : "transform-tutorial", + "timestampSpec": { + "column": "timestamp", + "format": "iso" + }, + "dimensionsSpec" : { + "dimensions" : [ + "animal", + { "name": "location", "type": "long" } + ] + }, + "metricsSpec" : [ + { "type" : "count", "name" : "count" }, + { "type" : "longSum", "name" : "number", "fieldName" : "number" }, + { "type" : "longSum", "name" : "triple-number", "fieldName" : "triple-number" } + ], + "granularitySpec" : { + "type" : "uniform", + "segmentGranularity" : "week", + "queryGranularity" : "minute", + "intervals" : ["2018-01-01/2018-01-03"], + "rollup" : true + }, + "transformSpec": { + "transforms": [ + { + "type": "expression", + "name": "animal", + "expression": "concat('super-', animal)" + }, + { + "type": "expression", + "name": "triple-number", + "expression": "number * 3" + } + ], + "filter": { + "type":"or", + "fields": [ + { "type": "selector", "dimension": "animal", "value": "super-mongoose" }, + { "type": "selector", "dimension": "triple-number", "value": "300" }, + { "type": "selector", "dimension": "location", "value": "3" } + ] + } + } + }, + "ioConfig" : { + "type" : "index_parallel", + "inputSource" : { + "type" : "local", + "baseDir" : "quickstart/tutorial", + "filter" : "transform-data.json" + }, + "inputFormat" : { + "type" :"json" + }, + "appendToExisting" : false + }, + "tuningConfig" : { + "type" : "index_parallel", + "partitionsSpec": { + "type": "dynamic" + }, + "maxRowsInMemory" : 25000 + } + } +} +``` + +In the transform spec, we have two expression transforms: +* `super-animal`: prepends "super-" to the values in the `animal` column. This will override the `animal` column with the transformed version, since the transform's name is `animal`. +* `triple-number`: multiplies the `number` column by 3. This will create a new `triple-number` column. Note that we are ingesting both the original and the transformed column. + +Additionally, we have an OR filter with three clauses: +* `super-animal` values that match "super-mongoose" +* `triple-number` values that match 300 +* `location` values that match 3 + +This filter selects the first 3 rows, and it will exclude the final "lion" row in the input data. Note that the filter is applied after the transformation. + +Let's submit this task now, which has been included at `quickstart/tutorial/transform-index.json`: + +```bash +bin/post-index-task --file quickstart/tutorial/transform-index.json --url http://localhost:8081 +``` + +## Query the transformed data + +Let's issue a `select * from "transform-tutorial";` query to the SQL API and see what data was ingested. + +```bash +curl -X POST -H "Content-Type: application/json" -d '{"query": "select * from \"transform-tutorial\""}' http://localhost:8888/druid/v2/sql +``` + Review Comment: Resolved by changes made by @edgar2020 https://github.com/apache/druid/pull/16845 -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
