Spark JDBC(1)MySQL Database RDD-优快云博客

本文链接：https://blog.youkuaiyun.com/magic_dreamer/article/details/84724246

本文详细介绍了如何使用Spark JDBC RDD从MySQL数据库中读取数据。首先客户端驱动连接到MySQL获取最小和最大ID，然后所有工作节点根据分区尝试获取数据。

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Spark JDBC(1)MySQL Database RDD

Try to understand how the JDBCRDD work on Spark.
First of all, the master did not connect to the database.

First step,
The client driver class will connect to the MySQL and get the minId and maxId.
150612 17:21:55 58 Connect cluster@192.168.56.1 on lmm
select coalesce(min(d.id), 0) from device d where d.last_updated >= '2014-06-12 00:00:00.0000' and d.last_updated < '2014-06-13 00:00:00.0000'
select coalesce(max(d.id), 0) from device d

Second step, All the workers will try to fetch the data based on partitions
150612 17:22:13 59 Connect cluster@ubuntu-dev2 on lmm
select id, tenant_id, date_created, last_updated, device_id, os_type, os_version,
search_radius, sdk_major_version, last_time_zone, sendable
from
device d
where
375001 <= d.id and
d.id <= 750001

select id, tenant_id, date_created, last_updated, device_id, os_type, os_version,
search_radius, sdk_major_version, last_time_zone, sendable
from
device d
where
750002 <= d.id and
d.id <= 1125002

62 Connect cluster@ubuntu-dev1 on lmm
62 Query select id, tenant_id, date_created, last_updated, device_id, os_type, os_version,
search_radius, sdk_major_version, last_time_zone, sendable
from
device d
where
0 <= d.id and
d.id <= 375000
63 Query select id, tenant_id, date_created, last_updated, device_id, os_type, os_version,
search_radius, sdk_major_version, last_time_zone, sendable
from
device d
where
1500004 <= d.id and
d.id <= 1875004

The sample JDBCRDD is in code
https://github.com/luohuazju/sillycat-spark/tree/streaming

References:
http://spark.apache.org/docs/1.4.0/tuning.html
http://stackoverflow.com/questions/27619230/how-to-split-the-input-file-in-apache-spark