CHRONIX SPARK TIME SERIES PROCESSING WITH SPARK Dr. Josef Adersberger ( @adersberger)

TIME SERIES 101

TIME SERIES 101 WE`RE SURROUNDED BY TIME SERIES ▸ Operational data: Monitoring data, performance metrics, log events, … ▸ Data Warehouse: Dimension time ▸ Measured Me: Activity tracking, ECG, … ▸ Sensor telemetry: Sensor data, … ▸ Financial data: Stock charts, … ▸ Climate data: Temperature, … ▸ Web tracking: Clickstreams, …

TIME SERIES 101 TIME SERIES: BASIC TERMS univariate time series multivariate time series multi-dimensional time series (time series tensor) time series set observation

TIME SERIES 101 OPERATIONS ON TIME SERIES (EXAMPLES) align Time series Time series Time series Scalar diff downsampling outlier min/max avg/med slope std-dev

OUR USE CASE

Monitoring Data Analysis 
 of a business-critical,
 worldwide distributed 
 software system. Enable
 root cause analysis and
 anomaly detection.
 > 1,000 nodes worldwide > 10 processes per node > 20 metrics per process
 (OS, JVM, App-spec.) Measured every second. = about 6.3 trillions observations p.a.
 Data retention: 5 yrs.

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http://www.datasciencecentral.com

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THE CHRONIX STACK THE CHRONIX STACK Core Chronix Storage Chronix Server Chronix Spark Chronix Format Grafana Chronix Analytics Collection Visualization Chronix Collector Logstash fluentd jmx collectd ssh Zeppelin

THE CHRONIX STACK node Distributed Data &
 Data Retrieval Distributed Processing Result Processing data flow icon credits to Nimal Raj (database), Arthur Shlain (console) and alvarobueno (takslist) } } Chronix Spark Chronix Server

USE CASE CHRONIX ANALYTICS: EXPLORING MULTI-DIMENSIONAL TIME SERIES

USE CASE CHRONIX ANALYTICS: ANOMALY DETECTION Featuring Twitter Anomaly Detection (https://github.com/twitter/AnomalyDetection
 and Yahoo EGDAS https://github.com/yahoo/egads

USE CASE ZEPPELIN ON CHRONIX

https://github.com/ChronixDB/chronix.spark

EASY-TO-USE BIG TIME SERIES DATA STORAGE & PROCESSING ON SPARK MISSION

MISSION (as well as for data scientists)

CHRONIX SPARK TIME SERIES MODEL Set of univariate multi-dimensional numeric time series ▸ set … because it’s more flexible and better to parallelise if operations can input and output multiple time series. ▸ univariate … because multivariate will introduce too much complexity (and we have our set to bundle multiple time series). ▸ multi-dimensional … because the ability to slice & dice in the set of time series is very convenient for a lot of use cases. ▸ numeric … because it’s the most common use case. A single time series is identified by a combination of its non-temporal dimensional values (e.g. unit “mem usage” + host “aws42” + process “tomcat”)

CHRONIX SPARK CHRONIX SPARK 
 ChronixRDD ChronixSparkContext ‣ Represents a set of time series ‣ Distributed operations on sets of time series ‣ Creates ChronixRDDs ‣ Speaks with the Chronix Server (Solr)

CHRONIX SPARK ChronixRDD transform to a Dataset extends transform to a DataFrame (SQL!) the set characteristic: 
 a JavaRDD of MetricTimeSeries

CHRONIX SPARK SPARK APIS FOR DATA PROCESSING RDD DataFrame Dataset typed yes no yes optimized medium highly highly mature yes yes no SQL no yes no

CHRONIX SPARK THE MetricTimeSeries DATA TYPE access all timestamps access all observations as stream the multi-dimensionality:
 get/set dimensions
 (attributes) access all numeric values
 (univariate)

CHRONIX SPARK THE OVERALL DATA MODEL ChronixRDD MetricTimeSeries MetricObservation Dataset Dataset DataFrame toDataFrame() toDataset() toObservationsDataset()

CHRONIX SPARK ChronixSparkContext RDD on all time series matched by a SolrQuery: /**
 * @param query Solr query
 * @param zkHost Zookeeper host
 * @param collection the Solr collection of chronix time series data
 * @param chronixStorage a ChronixSolrCloudStorage instance
 * @return ChronixRDD of time series
 */
 public ChronixRDD query(
 final SolrQuery query,
 final String zkHost,
 final String collection,
 final ChronixSolrCloudStorage chronixStorage) {

CHRONIX SPARK SAMPLE CODE //Create Chronix Spark context from a SparkContext / JavaSparkContext
 ChronixSparkContext csc = new ChronixSparkContext(sc);
 
 //Read data into ChronixRDD
 SolrQuery query = new SolrQuery(
 "metric:\"java.lang:type=Memory/HeapMemoryUsage/used\"");
 
 ChronixRDD rdd = csc.query(query,
 "localhost:9983", //ZooKeeper host
 "chronix", //Solr collection for Chronix
 new ChronixSolrCloudStorage());
 
 //Calculate the overall min/max/mean of all time series in the RDD
 double min = rdd.min();
 double max = rdd.max();
 double mean = rdd.mean();

DEMO TIME ‣ 8,707 time series with 76,983,735 observations ‣ one MacBook with 4 cores https://github.com/ChronixDB/chronix.spark/tree/master/chronix-infrastructure-local

A TRIP TO
 
 CHRONIX SPARK
 
 WONDERLAND

CHRONIX SPARK WONDERLAND ‣ Data sharding ‣ Fast index-based queries and aggregations ‣ Efficient storage format ‣ Heavy lifting distributed processing ‣ Catalyst processing optimizer ‣ Post-processing on a smaller set of time series (e.g. complex analysis algorithms)

CHRONIX SPARK WONDERLAND } } Chronix Spark Chronix Server

… with a few custom extensions. ▸ Index machine. ▸ Powerful query language based on Lucene. Powerful aggregation features (facets). E.g. groups way better than Spark.

CHRONIX SPARK WONDERLAND ARCHITECTURE Shard2 Solr Server Zookeeper Solr Server Solr Server Shard1 Zookeeper Zookeeper Zookeeper Cluster Solr Cloud Leader Scale Out Shard3 Replica8 Replica9 Shard5 Shard4 Shard6 Shard8 Shard7 Shard9 Replica2 Replica3 Replica5 Shards Replicas Collection Replica4 Replica7 Replica1 Shard6

CHRONIX SPARK WONDERLAND STORAGE FORMAT TIME SERIES ‣ start: TimeStamp ‣ end: TimeStamp ‣ unit: String ‣ dimensions: Map ‣ values: byte[] TIME SERIES ‣ start: TimeStamp ‣ end: TimeStamp ‣ unit: String ‣ dimensions: Map ‣ values: byte[] TIME SERIES ‣ start: TimeStamp ‣ end: TimeStamp ‣ unit: String ‣ dimensions: Map ‣ values: byte[] ▸ Chunking:
 1 logical time series = n physical time series all with the same identity containing a fixed amount of observations. 1 chunk = 1 solr document. ▸ Binary encoding of all
 timestamp/value pairs. Delta-encoded and bitwise compressed. Logical Physical

CHRONIX SPARK WONDERLAND CHRONIX FORMAT: OPTIMAL CHUNK SIZE AND COMPRESSION CODEC GZIP + 128 kBytes Florian Lautenschlager, Michael Philippsen, Andreas Kumlehn, Josef Adersberger
 Chronix: Efficient Storage and Query of Operational Time Series International Conference on Software Maintenance and Evolution 2016 (submitted)

CHRONIX SPARK WONDERLAND BENCHMARK: STORAGE DEMAND Florian Lautenschlager, Michael Philippsen, Andreas Kumlehn, Josef Adersberger Chronix: Efficient Storage and Query of Operational Time Series International Conference on Software Maintenance and Evolution 2016 (submitted)

CHRONIX SPARK WONDERLAND BENCHMARK: PERFORMANCE Florian Lautenschlager, Michael Philippsen, Andreas Kumlehn, Josef Adersberger Chronix: Efficient Storage and Query of Operational Time Series International Conference on Software Maintenance and Evolution 2016 (submitted) DISCLAIMER: BENCHMARK ONLY PERFORMED ON ONE NODE ONLY

CHRONIX SPARK WONDERLAND } } Chronix Spark Chronix Server

CHRONIX SPARK WONDERLAND SolrDocument Solr Shard SolrDocument SolrDocument SolrDocument Solr Shard SolrDocument TimeSeries TimeSeries TimeSeries TimeSeries TimeSeries Partition Partition ChronixRDD Binary protocol 1 SolrDocument = 1 Chunk 1 Spark Partition = 1 Solr Shard

CHRONIX SPARK WONDERLAND ChronixRDD CREATION: GET THE CHUNKS public ChronixRDD queryChronixChunks(
 final SolrQuery query,
 final String zkHost,
 final String collection,
 final ChronixSolrCloudStorage chronixStorage) throws SolrServerException, IOException {
 
 // first get a list of replicas to query for this collection
 List shards = chronixStorage.getShardList(zkHost, collection);
 
 // parallelize the requests to the shards
 JavaRDD docs = jsc.parallelize(shards, shards.size()).flatMap(
 (FlatMapFunction) shardUrl -> chronixStorage.streamFromSingleNode(
 new KassiopeiaSimpleConverter(), shardUrl, query)::iterator);
 return new ChronixRDD(docs);
 } Figure out all Solr shards Query each shard in parallel and convert SolrDocuments to MetricTimeSeries

CHRONIX SPARK WONDERLAND ChronixRDD CREATION: JOIN THEM TOGETHER TO A LOGICAL TIME SERIES public ChronixRDD joinChunks() {
 JavaPairRDD> groupRdd
 = this.groupBy(MetricTimeSeriesKey::new);
 
 JavaPairRDD joinedRdd
 = groupRdd.mapValues((Function, MetricTimeSeries>) mtsIt -> {
 MetricTimeSeriesOrdering ordering = new MetricTimeSeriesOrdering();
 List orderedChunks = ordering.immutableSortedCopy(mtsIt);
 MetricTimeSeries result = null;
 for (MetricTimeSeries mts : orderedChunks) {
 if (result == null) {
 result = new MetricTimeSeries
 .Builder(mts.getMetric())
 .attributes(mts.attributes()).build();
 }
 result.addAll(mts.getTimestampsAsArray(), mts.getValuesAsArray());
 }
 return result;
 });
 
 JavaRDD resultJavaRdd =
 joinedRdd.map((Tuple2 mtTuple) -> mtTuple._2);
 
 return new ChronixRDD(resultJavaRdd); } group chunks according identity join chunks to
 logical time 
 series

PERFORMANCE

PERFORMANCE THE SECRET OF DISTRIBUTED PERFORMANCE Rule 1: Be as close to the data as possible!
 (CPU cache > memory > local disk > network) Horizontal processing 
 (distribution / parallelization) Vertical processing 
 (divide & conquer) Rule 2: Reduce data volume as early as possible! 
 (as long as you don’t sacrifice parallelization) Rule 3: Parallelize as much as possible! 
 (max = #cores)

PERFORMANCE THE RULES APPLIED ‣ Rule 1: Be as close to the data as possible! 1. Solr caching 2. Spark in-memory processing with activated RDD compression 3. Binary protocol between Solr and Spark
 ‣ Rule 2: Reduce data volume as early as possible! ‣ Efficient storage format (Chronix Format) ‣ Predicate pushdown to Solr (query) ‣ Group-by & aggregation pushdown to Solr (faceting within a query)
 ‣ Rule 3: Parallelize as much as possible! ‣ Scale-out on data-level with SolrCloud ‣ Scale-out on processing-level with Spark

codingvoding.tumblr.com

RULE 4: PREMATURE OPTIMIZATION IS NOT EVIL 
 IF YOU HANDLE BIG DATA Josef Adersberger

PERFORMANCE USING A JAVA PROFILER WITH A LOCAL CLUSTER

PERFORMANCE HIGH-PERFORMANCE, LOW-OVERHEAD COLLECTIONS

PERFORMANCE 830 MB -> 360 MB
 (- 57%) unveiled wrong Jackson 
 handling inside of SolrClient

PERFORMANCE PROFILING ChronixRDD WITH PLAIN VANILLA SPARK Watch out 
 for branches! Watch out 
 for shuffling!

ROADMAP

ROADMAP THINGS TO COME see https://github.com/ChronixDB/chronix.spark/issues v0.4
 (06/16) v0.5
 (08/16) v0.6
 (10/16) v1.0
 (12/16) More actions and transformations Bulk transfer Solr request handler Streaming access R wrapper Reduce memory overhead Data locality (co- location) SparkML support Custom Dataset encoder SolrRDD adapter Incorporate alien technology

Johannes Josef Lukas Claudio Johannes Flaute Cloud THE CONTRIBUTORS YOU!

TWITTER.COM/QAWARE - SLIDESHARE.NET/QAWARE Thank you! Questions? [email protected] @adersberger https://github.com/ChronixDB/chronix.spark

BONUS SLIDES

THE COMPETITORS

THE COMPETITORS / ALTERNATIVES THE COMPETITORS / ALTERNATIVES ▸ Small Time Series Data ▸ Matlab (Econometrics toolbox) ▸ Python (Pandas) ▸ R (zoo, xts) ▸ SAS (ETS) ▸ … ▸ Big Time Series Data ▸ influxDB ▸ Graphite ▸ OpenTSDB ▸ KairosDB ▸ Prometheus ▸ …

THE COMPETITORS / ALTERNATIVES BIG DATA LANDSCAPE https://github.com/qaware/big-data-landscape

THE COMPETITORS / ALTERNATIVES CHRONIX RDD VS. SPARK-TS ▸ Spark-TS provides no specific time series storage it uses the Spark persistence mechanisms instead. This leads to a less efficient storage usage and less possibilities to perform performance optimizations via predicate pushdown. ▸ In contrast to Spark-TS Chronix does not align all time series values on one vector of timestamps. This leads to greater flexibility in time series aggregation ▸ Chronix provides multi-dimensional time series as this is very useful for data warehousing and APM. ▸ Chronix has support for Datasets as this will be an important Spark API in the near future. But Chronix currently doesn’t support an IndexedRowMatrix for SparkML. ▸ Chronix is purely written in Java. There is no explicit support for Python and Scala yet. ▸ Chronix doesn not support a ZonedTime as this makes it way more complicated.

APACHE SPARK 101

CHRONIX SPARK WONDERLAND ARCHITECTURE

APACHE SPARK SPARK TERMINOLOGY (1/2) ▸ RDD: Has transformations and actions. Hides data partitioning & distributed computation. References a set of partitions (“output partitions”) - materialized or not - and has dependencies to another RDD (“input partitions”). RDD operations are evaluated as late as possible (when an action is called). As long as not being the root RDD the partitions of an RDD are in memory but they can be persisted by request. ▸ Partitions: (Logical) chunks of data. Default unit and level of parallelism - inside of a partition everything is a sequential operation on records. Has to fit into memory. Can have different representations (in-memory, on disk, off heap, …)

APACHE SPARK SPARK TERMINOLOGY (2/2) ▸ Job: A computation job which is launched when an action is called on a RDD. ▸ Task: The atomic unit of work (function). Bound to exactly one partition. ▸ Stage: Set of Task pipelines which can be executed in parallel on one executor. ▸ Shuffling: If partitions need to be transferred between executors. Shuffle write = outbound partition transfer. Shuffle read = inbound partition transfer. ▸ DAG Scheduler: Computes DAG of stages from RDD DAG. Determines the preferred location for each task.