I am inserting to HBase using Spark but it's slow. For 60,000 records it takes 2-3mins. I have about 10 million records to save.
object WriteToHbase extends Serializable {
def main(args: Array[String]) {
val csvRows: RDD[Array[String] = ...
val dateFormatter = DateTimeFormat.forPattern("yyyy-MM-dd HH:mm:ss")
val usersRDD = csvRows.map(row => {
new UserTable(row(0), row(1), row(2), row(9), row(10), row(11))
})
processUsers(sc: SparkContext, usersRDD, dateFormatter)
})
}
def processUsers(sc: SparkContext, usersRDD: RDD[UserTable], dateFormatter: DateTimeFormatter): Unit = {
usersRDD.foreachPartition(part => {
val conf = HBaseConfiguration.create()
val table = new HTable(conf, tablename)
part.foreach(userRow => {
val id = userRow.id
val name = userRow.name
val date1 = dateFormatter.parseDateTime(userRow.date1)
val hRow = new Put(Bytes.toBytes(id))
hRow.add(cf, q, Bytes.toBytes(date1))
hRow.add(cf, q, Bytes.toBytes(name))
...
table.put(hRow)
})
table.flushCommits()
table.close()
})
}
I am using this in spark-submit:
--num-executors 2 --driver-memory 2G --executor-memory 2G --executor-cores 2
It's slow because the implementation doesn't leverage the proximity of the data; the piece of Spark RDD in a server may be transferred to a HBase RegionServer running on another server.
Currently there is no Spark's RRD operation to use HBase data store in efficient manner.
There is a batch api in Htable, you can try to send put requests as 100-500 put packets.I think it can speed up you a little. It returns individual result for every operation, so you can check failed puts if you want.
public void batch(List<? extends Row> actions, Object[] results)
https://hbase.apache.org/apidocs/org/apache/hadoop/hbase/client/HTable.html#batch%28java.util.List,%20java.lang.Object[]%29
You have to look on the approach where you can distribute your incoming data in to the Spark Job. In your current approach of foreachPartition instead you have to look on Transformations like map, mapToPair as well. You need to evaluate your whole DAG lifecycle and where you can save more time.
After that based on the Parallelism achieved you can call saveAsNewAPIHadoopDataset Action of Spark to write inside HBase more fast and parallel. Like:
JavaPairRDD<ImmutableBytesWritable, Put> yourFinalRDD = yourRDD.<SparkTransformation>{()};
yourFinalRDD.saveAsNewAPIHadoopDataset(yourHBaseConfiguration);
Note: Where yourHBaseConfiguration will be a singleton and will be single object on an Executor node to share between the Tasks
Kindly let me know if this Pseudo-code doesn't work for you or find any difficulty on the same.
Related
I've written some code with Akka Streams and Alpakka that reads from Amazon SQS and indexes the events in Elasticsearch. Everything works smoothly and the performance is awesome, but I have a problem with index names. I have this code:
class ElasticSearchIndexFlow(restClient: RestClient) {
private val elasticSettings = ElasticsearchSinkSettings(bufferSize = 10)
def flow: Flow[IncomingMessage[DomainEvent, NotUsed], Seq[IncomingMessageResult[DomainEvent, NotUsed]], NotUsed] =
ElasticsearchFlow.create[DomainEvent](index, "domain-event", elasticSettings)(
restClient,
DomainEventMarshaller.domainEventWrites
)
private def index = {
val now = DateTime.now()
s"de-${now.getYear}.${now.getMonthOfYear}.${now.getDayOfMonth}"
}
}
The problem is that after some days running the flow, the index name is not changing. I imagine that Akka Streams creates under the hood a fused actor, and that the function index for getting the index name is only evaluated at the beginning of execution.
Any idea of what can I do to index events in ES with an index name according to the current date?
The solution to the problem is setting the index name in previous step with IncomingMessage.withIndexName
So:
def flow: Flow[(DomainEvent, Message), IncomingMessage[DomainEvent, Message], NotUsed] =
Flow[(DomainEvent, Message)].map {
case (domainEvent, message) =>
IncomingMessage(Some(domainEvent.eventId), domainEvent, message)
.withIndexName(indexName(domainEvent.ocurredOn))
}
And:
def flow: Flow[IncomingMessage[DomainEvent, NotUsed], Seq[IncomingMessageResult[DomainEvent, NotUsed]], NotUsed] =
ElasticsearchFlow.create[DomainEvent]("this-index-name-is-not-used", "domain-event", elasticSettings)(
restClient,
DomainEventMarshaller.domainEventWrites
)
I have a spark streaming application which is responsible for converting text files into parquet format on the fly, and then saving the data in an external hive table. Please refer the mentioned piece of code which is one of the classes for processing text files into parquet:
object HistTableLogic {val logger = Logger.getLogger("file")
def schemadef(batchId: String) {
println("process started!")
logger.debug("process started")
val sourcePath = "some path"
val destPath = "somepath"
println(s"source path :${sourcePath}")
println(s"dest path :${destPath}")
logger.debug(s"source path :${sourcePath}")
logger.debug(s"dest path :${destPath}")
// val sc = new SparkContext(new SparkConf().set("spark.driver.allowMultipleContexts", "true"))
val conf = new Configuration()
println("Spark Context created!!")
logger.debug("Spark Context created!!")
val spark = SparkSession.builder.enableHiveSupport().getOrCreate()
println("Spark session created!")
logger.debug("Spark session created!")
val schema = StructType.apply(spark.read.table("hivetable").schema.fields.dropRight(2))
try {
val fs = FileSystem.get(conf)
spark.sql("ALTER table hivetable drop if exists partition (batch_run_dt='"+batchId.substring(1,9)+"', batchid='"+batchId+"')")
fs.listStatus(new Path(sourcePath)).foreach(x => {
val df = spark.read.format("com.databricks.spark.csv").option("inferSchema","true").option("delimiter","\u0001").
schema(schema).csv(s"${sourcePath}/"+batchId).na.fill("").repartition(50).write.mode("overwrite").option("compression", "gzip")
.parquet(s"${destPath}/batch_run_dt="+batchId.substring(1,9)+"/batchid="+batchId)
spark.sql("ALTER table hivetable add partition (batch_run_dt='"+batchId.substring(1,9)+"', batchid='"+batchId+"')")
logger.debug("Partition added")
})
} catch {
case e: Exception => {
println("---------Exception caught---------!")
logger.debug("---------Exception caught---------!")
e.printStackTrace()
logger.debug(e.printStackTrace)
logger.debug(e.getMessage)
}
}
}}
I am passing schemadef method of above class in main method of another java class which has the logic of receiving batchIds 24x7, set via custom receiver.
Functionally the application runs fine, but is taking around 15 minutes to process even 1GB of data. And if I try to simply load the data into hive table through LOAD query, it happens within a minute.
referring below configuration for spark job:
SPARK_MASTER YARN
SPARK_DEPLOY-MODE CLUSTER
SPARK_DRIVER-MEMORY 13g
SPARK_NUM-EXECUTORS 6
SPARK_EXECUTOR-MEMORY 15g
SPARK_EXECUTOR-CORES 2
Please let me know if you find any flaw in this or any other optimization I can do to enhance this process. Thank you
I am running a Spark Streaming application based on mapWithState DStream function . The application transforms input records into sessions based on a session ID field inside the records.
A session is simply all of the records with the same ID . Then I perform some analytics on a session level to find an anomaly score.
I couldn't stabilize my application because a handful of sessions are getting bigger at each batch time for extended period ( more than 1h) . My understanding is a single session (key - value pair) is always processed by a single core in spark . I want to know if I am mistaken , and if there is a solution to mitigate this issue and make the streaming application stable.
I am using Hadoop 2.7.2 and Spark 1.6.1 on Yarn . Changing batch time, blocking interval , partitions number, executor number and executor resources didn't solve the issue as one single task makes the application always choke. However, filtering those super long sessions solved the issue.
Below is a code updateState function I am using :
val updateState = (batchTime: Time, key: String, value: Option[scala.collection.Map[String,Any]], state: State[Seq[scala.collection.Map[String,Any]]]) => {
val session = Seq(value.getOrElse(scala.collection.Map[String,Any]())) ++ state.getOption.getOrElse(Seq[scala.collection.Map[String,Any]]())
if (state.isTimingOut()) {
Option(null)
} else {
state.update(session)
Some((key,value,session))
}
}
and the mapWithStae call :
def updateStreamingState(inputDstream:DStream[scala.collection.Map[String,Any]]): DStream[(String,Option[scala.collection.Map[String,Any]], Seq[scala.collection.Map[String,Any]])] ={//MapWithStateDStream[(String,Option[scala.collection.Map[String,Any]], Seq[scala.collection.Map[String,Any]])] = {
val spec = StateSpec.function(updateState)
spec.timeout(Duration(sessionTimeout))
spec.numPartitions(192)
inputDstream.map(ds => (ds(sessionizationFieldName).toString, ds)).mapWithState(spec)
}
Finally I am applying a feature computing session foreach DStream , as defined below :
def computeSessionFeatures(sessionId:String,sessionRecords: Seq[scala.collection.Map[String,Any]]): Session = {
val features = Functions.getSessionFeatures(sessionizationFeatures,recordFeatures,sessionRecords)
val resultSession = new Session(sessionId,sessionizationFieldName,sessionRecords)
resultSession.features = features
return resultSession
}
So I want to write a code to read a record from Hadoop HBase then store it into Spark RDD (Resilient Distributed Datasets); and read one RDD record then write into HBase. I have ZERO knowledge about either of the two and I need to use AWS cloud or Hadoop virtual machine. Someone please guide me to start from scratch.
Please make use of the basic code in Scala where we are reading the data in HBase using Scala. Similarly you can write a table creation to write the data into HBase
import org.apache.hadoop.hbase.client.{HBaseAdmin, Result}
import org.apache.hadoop.hbase.{ HBaseConfiguration, HTableDescriptor }
import org.apache.hadoop.hbase.mapreduce.TableInputFormat
import org.apache.hadoop.hbase.io.ImmutableBytesWritable
import org.apache.spark._
object HBaseApp {
def main(args: Array[String]) {
val sparkConf = new SparkConf().setAppName("HBaseApp").setMaster("local[2]")
val sc = new SparkContext(sparkConf)
val conf = HBaseConfiguration.create()
val tableName = "table1"
System.setProperty("user.name", "hdfs")
System.setProperty("HADOOP_USER_NAME", "hdfs")
conf.set("hbase.master", "localhost:60000")
conf.setInt("timeout", 100000)
conf.set("hbase.zookeeper.quorum", "localhost")
conf.set("zookeeper.znode.parent", "/hbase-unsecure")
conf.set(TableInputFormat.INPUT_TABLE, tableName)
val admin = new HBaseAdmin(conf)
if (!admin.isTableAvailable(tableName)) {
val tableDesc = new HTableDescriptor(tableName)
admin.createTable(tableDesc)
}
val hBaseRDD = sc.newAPIHadoopRDD(conf, classOf[TableInputFormat], classOf[ImmutableBytesWritable], classOf[Result])
println("Number of Records found : " + hBaseRDD.count())
sc.stop()
}
}
There is a fair amount of info online about bulk loading to HBase with Spark streaming using Scala (these two were particularly useful) and some info for Java, but there seems to be a lack of info for doing it with PySpark. So my questions are:
How can data be bulk loaded into HBase using PySpark?
Most examples in any language only show a single column per row being upserted. How can I upsert multiple columns per row?
The code I currently have is as follows:
if __name__ == "__main__":
context = SparkContext(appName="PythonHBaseBulkLoader")
streamingContext = StreamingContext(context, 5)
stream = streamingContext.textFileStream("file:///test/input");
stream.foreachRDD(bulk_load)
streamingContext.start()
streamingContext.awaitTermination()
What I need help with is the bulk load function
def bulk_load(rdd):
#???
I've made some progress previously, with many and various errors (as documented here and here)
So after much trial and error, I present here the best I have come up with. It works well, and successfully bulk loads data (using Puts or HFiles) I am perfectly willing to believe that it is not the best method, so any comments/other answers are welcome. This assume you're using a CSV for your data.
Bulk loading with Puts
By far the easiest way to bulk load, this simply creates a Put request for each cell in the CSV and queues them up to HBase.
def bulk_load(rdd):
#Your configuration will likely be different. Insert your own quorum and parent node and table name
conf = {"hbase.zookeeper.qourum": "localhost:2181",\
"zookeeper.znode.parent": "/hbase-unsecure",\
"hbase.mapred.outputtable": "Test",\
"mapreduce.outputformat.class": "org.apache.hadoop.hbase.mapreduce.TableOutputFormat",\
"mapreduce.job.output.key.class": "org.apache.hadoop.hbase.io.ImmutableBytesWritable",\
"mapreduce.job.output.value.class": "org.apache.hadoop.io.Writable"}
keyConv = "org.apache.spark.examples.pythonconverters.StringToImmutableBytesWritableConverter"
valueConv = "org.apache.spark.examples.pythonconverters.StringListToPutConverter"
load_rdd = rdd.flatMap(lambda line: line.split("\n"))\#Split the input into individual lines
.flatMap(csv_to_key_value)#Convert the CSV line to key value pairs
load_rdd.saveAsNewAPIHadoopDataset(conf=conf,keyConverter=keyConv,valueConverter=valueConv)
The function csv_to_key_value is where the magic happens:
def csv_to_key_value(row):
cols = row.split(",")#Split on commas.
#Each cell is a tuple of (key, [key, column-family, column-descriptor, value])
#Works well for n>=1 columns
result = ((cols[0], [cols[0], "f1", "c1", cols[1]]),
(cols[0], [cols[0], "f2", "c2", cols[2]]),
(cols[0], [cols[0], "f3", "c3", cols[3]]))
return result
The value converter we defined earlier will convert these tuples into HBase Puts
Bulk loading with HFiles
Bulk loading with HFiles is more efficient: rather than a Put request for each cell, an HFile is written directly and the RegionServer is simply told to point to the new HFile. This will use Py4J, so before the Python code we have to write a small Java program:
import py4j.GatewayServer;
import org.apache.hadoop.hbase.*;
public class GatewayApplication {
public static void main(String[] args)
{
GatewayApplication app = new GatewayApplication();
GatewayServer server = new GatewayServer(app);
server.start();
}
}
Compile this, and run it. Leave it running as long as your streaming is happening. Now update bulk_load as follows:
def bulk_load(rdd):
#The output class changes, everything else stays
conf = {"hbase.zookeeper.qourum": "localhost:2181",\
"zookeeper.znode.parent": "/hbase-unsecure",\
"hbase.mapred.outputtable": "Test",\
"mapreduce.outputformat.class": "org.apache.hadoop.hbase.mapreduce.HFileOutputFormat2",\
"mapreduce.job.output.key.class": "org.apache.hadoop.hbase.io.ImmutableBytesWritable",\
"mapreduce.job.output.value.class": "org.apache.hadoop.io.Writable"}#"org.apache.hadoop.hbase.client.Put"}
keyConv = "org.apache.spark.examples.pythonconverters.StringToImmutableBytesWritableConverter"
valueConv = "org.apache.spark.examples.pythonconverters.StringListToPutConverter"
load_rdd = rdd.flatMap(lambda line: line.split("\n"))\
.flatMap(csv_to_key_value)\
.sortByKey(True)
#Don't process empty RDDs
if not load_rdd.isEmpty():
#saveAsNewAPIHadoopDataset changes to saveAsNewAPIHadoopFile
load_rdd.saveAsNewAPIHadoopFile("file:///tmp/hfiles" + startTime,
"org.apache.hadoop.hbase.mapreduce.HFileOutputFormat2",
conf=conf,
keyConverter=keyConv,
valueConverter=valueConv)
#The file has now been written, but HBase doesn't know about it
#Get a link to Py4J
gateway = JavaGateway()
#Convert conf to a fully fledged Configuration type
config = dict_to_conf(conf)
#Set up our HTable
htable = gateway.jvm.org.apache.hadoop.hbase.client.HTable(config, "Test")
#Set up our path
path = gateway.jvm.org.apache.hadoop.fs.Path("/tmp/hfiles" + startTime)
#Get a bulk loader
loader = gateway.jvm.org.apache.hadoop.hbase.mapreduce.LoadIncrementalHFiles(config)
#Load the HFile
loader.doBulkLoad(path, htable)
else:
print("Nothing to process")
Finally, the fairly straightforward dict_to_conf:
def dict_to_conf(conf):
gateway = JavaGateway()
config = gateway.jvm.org.apache.hadoop.conf.Configuration()
keys = conf.keys()
vals = conf.values()
for i in range(len(keys)):
config.set(keys[i], vals[i])
return config
As you can see, bulk loading with HFiles is more complex than using Puts, but depending on your data load it is probably worth it since once you get it working it's not that difficult.
One last note on something that caught me off guard: HFiles expect the data they receive to be written in lexical order. This is not always guaranteed to be true, especially since "10" < "9". If you have designed your key to be unique, then this can be fixed easily:
load_rdd = rdd.flatMap(lambda line: line.split("\n"))\
.flatMap(csv_to_key_value)\
.sortByKey(True)#Sort in ascending order