Ádám Szita created HIVE-22583:
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             Summary: LLAP cache always misses with non-vectorized serde 
readers such as OpenCSV
                 Key: HIVE-22583
                 URL: https://issues.apache.org/jira/browse/HIVE-22583
             Project: Hive
          Issue Type: Bug
          Components: llap
            Reporter: Ádám Szita
            Assignee: Ádám Szita


Although after the first read LLAP cache stores data of tables that are not 
using the LazySimple serde, the stored data is then never used in the future 
subsequent queries, causing a full cache miss and re-read each time.

Problem is rooted in SerdeEncodedDataReader#cacheFileData is not taking care of 
creating an entry for the root/struct column of the table. The only cases this 
is taken care of are when a vectorized reader is used _(e.g. LazySimpleSerde's 
LazySimpleDeserializeRead)_, where SerdeEncodedDataReader#processAsyncCacheData 
takes care of this.

This can be reproduced by either using a custom serde, like OpenCSV or using 
LazySimpleSerde, but turning off _hive.llap.io.encode.vector.serde.enabled_.



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