How a plan is split into Job and stage in Spark? -

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i'm trying understand how query plan splitted job in spark, how spark decide split workflow in job , stage.

my query simple join between big table (22gb) , small table (300mb): 

select key0 bigtable,smalltable importedkey=keysmalltable

and execute shuffledhashjoin , broadcasthashjoin.

for shuffledhashjoin 1 job:

enter image description here

and 4 stage:

enter image description here

for broadcasthashjoin 3 job:

enter image description here

and 4 stage:

enter image description here

enter image description here enter image description here

this job's division caused "collect" on driver required when use broadcasthashjoin?


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