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https://issues.apache.org/jira/browse/HIVE-20377?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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slim bouguerra updated HIVE-20377:
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Attachment: HIVE-20377.8.patch
> Hive Kafka Storage Handler
> --------------------------
>
> Key: HIVE-20377
> URL: https://issues.apache.org/jira/browse/HIVE-20377
> Project: Hive
> Issue Type: New Feature
> Affects Versions: 4.0.0
> Reporter: slim bouguerra
> Assignee: slim bouguerra
> Priority: Major
> Attachments: HIVE-20377.4.patch, HIVE-20377.5.patch,
> HIVE-20377.6.patch, HIVE-20377.8.patch, HIVE-20377.patch
>
>
> h1. Goal
> * Read streaming data form Kafka queue as an external table.
> * Allow streaming navigation by pushing down filters on Kafka record
> partition id, offset and timestamp.
> * Insert streaming data form Kafka to an actual Hive internal table, using
> CTAS statement.
> h1. Example
> h2. Create the external table
> {code}
> CREATE EXTERNAL TABLE kafka_table (`timestamp` timestamp, page string, `user`
> string, language string, added int, deleted int, flags string,comment string,
> namespace string)
> STORED BY 'org.apache.hadoop.hive.kafka.KafkaStorageHandler'
> TBLPROPERTIES
> ("kafka.topic" = "wikipedia",
> "kafka.bootstrap.servers"="brokeraddress:9092",
> "kafka.serde.class"="org.apache.hadoop.hive.serde2.JsonSerDe");
> {code}
> h2. Kafka Metadata
> In order to keep track of Kafka records the storage handler will add
> automatically the Kafka row metadata eg partition id, record offset and
> record timestamp.
> {code}
> DESCRIBE EXTENDED kafka_table
> timestamp timestamp from deserializer
> page string from deserializer
> user string from deserializer
> language string from deserializer
> country string from deserializer
> continent string from deserializer
> namespace string from deserializer
> newpage boolean from deserializer
> unpatrolled boolean from deserializer
> anonymous boolean from deserializer
> robot boolean from deserializer
> added int from deserializer
> deleted int from deserializer
> delta bigint from deserializer
> __partition int from deserializer
> __offset bigint from deserializer
> __timestamp bigint from deserializer
> {code}
> h2. Filter push down.
> Newer Kafka consumers 0.11.0 and higher allow seeking on the stream based on
> a given offset. The proposed storage handler will be able to leverage such
> API by pushing down filters over metadata columns, namely __partition (int),
> __offset(long) and __timestamp(long)
> For instance Query like
> {code}
> select `__offset` from kafka_table where (`__offset` < 10 and `__offset`>3
> and `__partition` = 0) or (`__partition` = 0 and `__offset` < 105 and
> `__offset` > 99) or (`__offset` = 109);
> {code}
> Will result on a scan of partition 0 only then read only records between
> offset 4 and 109.
> h2. With timestamp seeks
> The seeking based on the internal timestamps allows the handler to run on
> recently arrived data, by doing
> {code}
> select count(*) from kafka_table where `__timestamp` > 1000 *
> to_unix_timestamp(CURRENT_TIMESTAMP - interval '20' hours) ;
> {code}
> This allows for implicit relationships between event timestamps and kafka
> timestamps to be expressed in queries (i.e event_timestamp is always < than
> kafka __timestamp and kafka __timestamp is never > 15 minutes from event etc).
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