Amazon EMR
Amazon EMR Release Guide

Using HCatalog

You can use HCatalog within various applications that use the Hive metastore. The examples in this section show how to create a table and use it in the context of Pig and Spark SQL.

Disable Direct Write When Using HCatalog HStorer

Whenever an application uses HCatStorer to write to an HCatalog table stored in Amazon S3, disable the direct write feature of Amazon EMR. For example, disable direct write when using the Pig STORE command or when running Sqoop jobs that write HCatalog tables to Amazon S3. You can disable the direct write feature by setting the mapred.output.direct.NativeS3FileSystem and the mapred.output.direct.EmrFileSystem configurations to false. The following example demonstrates how to set these configurations using Java.

Configuration conf = new Configuration(); conf.set("mapred.output.direct.NativeS3FileSystem", "false"); conf.set("mapred.output.direct.EmrFileSystem", "false");

Create a Table Using the HCat CLI and Use That Data in Pig

Create the following script, impressions.q, on your cluster:

CREATE EXTERNAL TABLE impressions ( requestBeginTime string, adId string, impressionId string, referrer string, userAgent string, userCookie string, ip string ) PARTITIONED BY (dt string) ROW FORMAT serde 'org.apache.hive.hcatalog.data.JsonSerDe' with serdeproperties ( 'paths'='requestBeginTime, adId, impressionId, referrer, userAgent, userCookie, ip' ) LOCATION 's3://[your region].elasticmapreduce/samples/hive-ads/tables/impressions/'; ALTER TABLE impressions ADD PARTITION (dt='2009-04-13-08-05');

Execute the script using the HCat CLI:

% hcat -f impressions.q Logging initialized using configuration in file:/etc/hive/conf.dist/hive-log4j.properties OK Time taken: 4.001 seconds OK Time taken: 0.519 seconds

Open the Grunt shell and access the data in impressions:

% pig -useHCatalog -e "A = LOAD 'impressions' USING org.apache.hive.hcatalog.pig.HCatLoader(); B = LIMIT A 5; dump B;" <snip> (1239610346000,m9nwdo67Nx6q2kI25qt5On7peICfUM,omkxkaRpNhGPDucAiBErSh1cs0MThC,cartoonnetwork.com,Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0; FunWebProducts; GTB6; SLCC1; .NET CLR 2.0.50727; Media Center PC 5.0; .NET,wcVWWTascoPbGt6bdqDbuWTPPHgOPs,69.191.224.234,2009-04-13-08-05) (1239611000000,NjriQjdODgWBKnkGJUP6GNTbDeK4An,AWtXPkfaWGOaNeL9OOsFU8Hcj6eLHt,cartoonnetwork.com,Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; GTB6; .NET CLR 1.1.4322),OaMU1F2gE4CtADVHAbKjjRRks5kIgg,57.34.133.110,2009-04-13-08-05) (1239610462000,Irpv3oiu0I5QNQiwSSTIshrLdo9cM1,i1LDq44LRSJF0hbmhB8Gk7k9gMWtBq,cartoonnetwork.com,Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; SV1; .NET CLR 1.1.4322; InfoPath.1),QSb3wkLR4JAIut4Uq6FNFQIR1rCVwU,42.174.193.253,2009-04-13-08-05) (1239611007000,q2Awfnpe0JAvhInaIp0VGx9KTs0oPO,s3HvTflPB8JIE0IuM6hOEebWWpOtJV,cartoonnetwork.com,Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; SV1; .NET CLR 1.1.4322; InfoPath.1),QSb3wkLR4JAIut4Uq6FNFQIR1rCVwU,42.174.193.253,2009-04-13-08-05) (1239610398000,c362vpAB0soPKGHRS43cj6TRwNeOGn,jeas5nXbQInGAgFB8jlkhnprN6cMw7,cartoonnetwork.com,Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; GTB6; .NET CLR 1.1.4322),k96n5PnUmwHKfiUI0TFP0TNMfADgh9,51.131.29.87,2009-04-13-08-05) 7120 [main] INFO org.apache.pig.Main - Pig script completed in 7 seconds and 199 milliseconds (7199 ms) 16/03/08 23:17:10 INFO pig.Main: Pig script completed in 7 seconds and 199 milliseconds (7199 ms)

Accessing the Table using Spark SQL

This example creates a Spark DataFrame from the table created in the first example and shows the first 20 lines:

% spark-shell --jars /usr/lib/hive-hcatalog/share/hcatalog/hive-hcatalog-core-1.0.0-amzn-3.jar <snip> scala> val hiveContext = new org.apache.spark.sql.hive.HiveContext(sc); scala> val df = hiveContext.sql("SELECT * FROM impressions") scala> df.show() <snip> 16/03/09 17:18:46 INFO DAGScheduler: ResultStage 0 (show at <console>:32) finished in 10.702 s 16/03/09 17:18:46 INFO DAGScheduler: Job 0 finished: show at <console>:32, took 10.839905 s +----------------+--------------------+--------------------+------------------+--------------------+--------------------+--------------+----------------+ |requestbegintime| adid| impressionid| referrer| useragent| usercookie| ip| dt| +----------------+--------------------+--------------------+------------------+--------------------+--------------------+--------------+----------------+ | 1239610346000|m9nwdo67Nx6q2kI25...|omkxkaRpNhGPDucAi...|cartoonnetwork.com|Mozilla/4.0 (comp...|wcVWWTascoPbGt6bd...|69.191.224.234|2009-04-13-08-05| | 1239611000000|NjriQjdODgWBKnkGJ...|AWtXPkfaWGOaNeL9O...|cartoonnetwork.com|Mozilla/4.0 (comp...|OaMU1F2gE4CtADVHA...| 57.34.133.110|2009-04-13-08-05| | 1239610462000|Irpv3oiu0I5QNQiwS...|i1LDq44LRSJF0hbmh...|cartoonnetwork.com|Mozilla/4.0 (comp...|QSb3wkLR4JAIut4Uq...|42.174.193.253|2009-04-13-08-05| | 1239611007000|q2Awfnpe0JAvhInaI...|s3HvTflPB8JIE0IuM...|cartoonnetwork.com|Mozilla/4.0 (comp...|QSb3wkLR4JAIut4Uq...|42.174.193.253|2009-04-13-08-05| | 1239610398000|c362vpAB0soPKGHRS...|jeas5nXbQInGAgFB8...|cartoonnetwork.com|Mozilla/4.0 (comp...|k96n5PnUmwHKfiUI0...| 51.131.29.87|2009-04-13-08-05| | 1239610600000|cjBTpruoaiEtqLuMX...|XwlohBSs8Ipxs1bRa...|cartoonnetwork.com|Mozilla/4.0 (comp...|k96n5PnUmwHKfiUI0...| 51.131.29.87|2009-04-13-08-05| | 1239610804000|Ms3eJHNAEItpxvimd...|4SIj4pGmgVLl625BD...|cartoonnetwork.com|Mozilla/4.0 (comp...|k96n5PnUmwHKfiUI0...| 51.131.29.87|2009-04-13-08-05| | 1239610872000|h5bccHX6wJReDi1jL...|EFAWIiBdVfnxwAMWP...|cartoonnetwork.com|Mozilla/4.0 (comp...|k96n5PnUmwHKfiUI0...| 51.131.29.87|2009-04-13-08-05| | 1239610365000|874NBpGmxNFfxEPKM...|xSvE4XtGbdtXPF2Lb...|cartoonnetwork.com|Mozilla/5.0 (Maci...|eWDEVVUphlnRa273j...| 22.91.173.232|2009-04-13-08-05| | 1239610348000|X8gISpUTSqh1A5reS...|TrFblGT99AgE75vuj...| corriere.it|Mozilla/4.0 (comp...|tX1sMpnhJUhmAF7AS...| 55.35.44.79|2009-04-13-08-05| | 1239610743000|kbKreLWB6QVueFrDm...|kVnxx9Ie2i3OLTxFj...| corriere.it|Mozilla/4.0 (comp...|tX1sMpnhJUhmAF7AS...| 55.35.44.79|2009-04-13-08-05| | 1239610812000|9lxOSRpEi3bmEeTCu...|1B2sff99AEIwSuLVV...| corriere.it|Mozilla/4.0 (comp...|tX1sMpnhJUhmAF7AS...| 55.35.44.79|2009-04-13-08-05| | 1239610876000|lijjmCf2kuxfBTnjL...|AjvufgUtakUFcsIM9...| corriere.it|Mozilla/4.0 (comp...|tX1sMpnhJUhmAF7AS...| 55.35.44.79|2009-04-13-08-05| | 1239610941000|t8t8trgjNRPIlmxuD...|agu2u2TCdqWP08rAA...| corriere.it|Mozilla/4.0 (comp...|tX1sMpnhJUhmAF7AS...| 55.35.44.79|2009-04-13-08-05| | 1239610490000|OGRLPVNGxiGgrCmWL...|mJg2raBUpPrC8OlUm...| corriere.it|Mozilla/4.0 (comp...|r2k96t1CNjSU9fJKN...| 71.124.66.3|2009-04-13-08-05| | 1239610556000|OnJID12x0RXKPUgrD...|P7Pm2mPdW6wO8KA3R...| corriere.it|Mozilla/4.0 (comp...|r2k96t1CNjSU9fJKN...| 71.124.66.3|2009-04-13-08-05| | 1239610373000|WflsvKIgOqfIE5KwR...|TJHd1VBspNcua0XPn...| corriere.it|Mozilla/5.0 (Maci...|fj2L1ILTFGMfhdrt3...| 75.117.56.155|2009-04-13-08-05| | 1239610768000|4MJR0XxiVCU1ueXKV...|1OhGWmbvKf8ajoU8a...| corriere.it|Mozilla/5.0 (Maci...|fj2L1ILTFGMfhdrt3...| 75.117.56.155|2009-04-13-08-05| | 1239610832000|gWIrpDiN57i3sHatv...|RNL4C7xPi3tdar2Uc...| corriere.it|Mozilla/5.0 (Maci...|fj2L1ILTFGMfhdrt3...| 75.117.56.155|2009-04-13-08-05| | 1239610789000|pTne9k62kJ14QViXI...|RVxJVIQousjxUVI3r...| pixnet.net|Mozilla/5.0 (Maci...|1bGOKiBD2xmui9OkF...| 33.176.101.80|2009-04-13-08-05| +----------------+--------------------+--------------------+------------------+--------------------+--------------------+--------------+----------------+ only showing top 20 rows scala>