roadahead / druid-spark-batch

Druid indexing plugin for using Spark in batch jobs

druid-spark-batch

Druid indexing plugin for using Spark in batch jobs

This repository holds a Druid extension for using Spark as the engine for running batch jobs

To build issue the commnand JAVA_HOME=$(/usr/libexec/java_home -v 1.7) sbt clean test publish-local publish-m2

Default Properties

The default properties injected into spark are as follows:

    .set("spark.executor.memory", "7G")
    .set("spark.executor.cores", "1")
    .set("spark.kryo.referenceTracking", "false")
    .set("user.timezone", "UTC")
    .set("file.encoding", "UTF-8")
    .set("java.util.logging.manager", "org.apache.logging.log4j.jul.LogManager")
    .set("org.jboss.logging.provider", "slf4j")

To use this extension, the hadoop client libraries and spark assembly (which might include the hadoop libraries) should be on the classpath of the overlord or middle manager. And the following should be added to druid.extensions.coordinates : io.druid.extensions:druid-spark-batch_2.10:jar:assembly:0.0.13 (obviously with the corrected version for whichever version you are using)

How to use

There are four key things that need configured to use this extension

1. Overlord needs the druid-spark-batch extension added.
2. MiddleManager (if present) needs the druid-spark-batch extension added.
3. A task json needs configured.
4. Spark is included in the default hadoop coordinates similar to druid.indexer.task.defaultHadoopCoordinates=["org.apache.spark:spark-core_2.10:1.5.2-mmx0"]

To load the extension, use the appropriate coordinates (for druid 0.8.x ) or make certain the extension jars are located in the proper directories (druid 0.9.x and later)

Task JSON

The following is an example spark batch task for the indexing service:

{
    "dataFiles":["file:///Users/charlesallen/bin/wrk/lineitem.small.tbl"],
    "dataSchema": {
        "dataSource": "sparkTest",
        "granularitySpec": {
            "intervals": [
                "1992-01-01T00:00:00.000Z/1999-01-01T00:00:00.000Z"
            ],
            "queryGranularity": {
                "type": "all"
            },
            "segmentGranularity": "YEAR",
            "type": "uniform"
        },
        "metricsSpec": [
            {
                "name": "count",
                "type": "count"
            },
            {
                "fieldName": "l_quantity",
                "name": "L_QUANTITY_longSum",
                "type": "longSum"
            },
            {
                "fieldName": "l_extendedprice",
                "name": "L_EXTENDEDPRICE_doubleSum",
                "type": "doubleSum"
            },
            {
                "fieldName": "l_discount",
                "name": "L_DISCOUNT_doubleSum",
                "type": "doubleSum"
            },
            {
                "fieldName": "l_tax",
                "name": "L_TAX_doubleSum",
                "type": "doubleSum"
            }
        ],
        "parser": {
            "encoding": "UTF-8",
            "parseSpec": {
                "columns": [
                    "l_orderkey",
                    "l_partkey",
                    "l_suppkey",
                    "l_linenumber",
                    "l_quantity",
                    "l_extendedprice",
                    "l_discount",
                    "l_tax",
                    "l_returnflag",
                    "l_linestatus",
                    "l_shipdate",
                    "l_commitdate",
                    "l_receiptdate",
                    "l_shipinstruct",
                    "l_shipmode",
                    "l_comment"
                ],
                "delimiter": "|",
                "dimensionsSpec": {
                    "dimensionExclusions": [
                        "l_tax",
                        "l_quantity",
                        "count",
                        "l_extendedprice",
                        "l_shipdate",
                        "l_discount"
                    ],
                    "dimensions": [
                        "l_comment",
                        "l_commitdate",
                        "l_linenumber",
                        "l_linestatus",
                        "l_orderkey",
                        "l_receiptdate",
                        "l_returnflag",
                        "l_shipinstruct",
                        "l_shipmode",
                        "l_suppkey"
                    ],
                    "spatialDimensions": []
                },
                "format": "tsv",
                "listDelimiter": ",",
                "timestampSpec": {
                    "column": "l_shipdate",
                    "format": "yyyy-MM-dd",
                    "missingValue": null
                }
            },
            "type": "string"
        }
    },
    "dataSource": "someDataSource",
    "indexSpec": {
        "bitmap": {
            "type": "concise"
        },
        "dimensionCompression": "lz4",
        "metricCompression": "lz4"
    },
    "intervals": ["1992-01-01T00:00:00.000Z/1999-01-01T00:00:00.000Z"],
    "master": "local[1]",
    "properties": {
        "some.property": "someValue",
        "spark.io.compression.codec":"org.apache.spark.io.LZ4CompressionCodec"
    },
    "targetPartitionSize": 10000000,
    "type": "index_spark"
}

The json keys accepted by the spark batch indexer are described below

Batch indexer json fields

Field	Type	Required	Default	Description
type	String	Yes, index_spark	N/A	Must be index_spark
paths	List of strings	Yes	N/A	A list of hadoop-readable input files. The values are joined with a , and used as a SparkContext.textFile
dataSchema	DataSchema	Yes	N/A	The data schema to use
intervals	List of strings	Yes	N/A	A list of ISO intervals to be indexed. ALL data for these intervals MUST be present in paths
maxRowsInMemory	positive integer	No	80000	Maximum number of rows to store in memory before an intermediate flush to disk
targetPartitionSize	positive integer	No	5000000	The target number of rows per partition per segment granularity
master	String	No	master[1]	The spark master URI
properties	Map	No	none	A map of string key/value pairs to inject into the SparkContext properties overriding any prior set values
id	String	No	Assigned based on dataSource, intervals, and DateTime.now()	The ID for the task. If not provied it will be assigned
indexSpec	InputSpec	No	concise, lz4, lz4	The InputSpec containing the various compressions to be used
context	Map	No	none	The task context