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Joe McDonnell resolved IMPALA-9112. ----------------------------------- Fix Version/s: Not Applicable Resolution: Won't Fix The consistency aspect of this will no longer apply. S3 now has strong consistency: [https://aws.amazon.com/s3/consistency/] I'm going to close this. We can consider performance aspects in a separate JIRA. > Consider removing hdfsExists calls when writing files to S3 > ----------------------------------------------------------- > > Key: IMPALA-9112 > URL: https://issues.apache.org/jira/browse/IMPALA-9112 > Project: IMPALA > Issue Type: Improvement > Components: Backend > Reporter: Sahil Takiar > Assignee: Sahil Takiar > Priority: Major > Fix For: Not Applicable > > > There are a few places in the backend where we call {{hdfsExists}} before > writing out a file. This can cause issues when writing data to S3, because S3 > can cache 404 Not Found errors. This issue manifests itself with errors such > as: > {code:java} > ERROR: Error(s) moving partition files. First error (of 1) was: Hdfs op > (RENAME > s3a://[bucket-name]/[table-name]/_impala_insert_staging/3943ae7ccf00711e_59606d8800000000/.3943ae7ccf00711e-59606d880000000b_562151879_dir/year=2015/3943ae7ccf00711e-59606d880000000b_1994902389_data.0.parq > TO > s3a://[bucket-name]/[table-name]/3943ae7ccf00711e-59606d880000000b_1994902389_data.0.parq) > failed, error was: > s3a://[bucket-name]/[table-name]/_impala_insert_staging/3943ae7ccf00711e_59606d8800000000/.3943ae7ccf00711e-59606d880000000b_562151879_dir/year=2015/3943ae7ccf00711e-59606d880000000b_1994902389_data.0.parq > Error(5): Input/output error > Root cause: AmazonS3Exception: Not Found (Service: Amazon S3; Status Code: > 404; Error Code: 404 Not Found; Request ID: []; S3 Extended Request ID: > []){code} > HADOOP-13884, HADOOP-13950, HADOOP-16490 - the HDFS clients allow specifying > an "overwrite" option when creating a file; this can avoid doing any HEAD > requests when opening a file. -- This message was sent by Atlassian Jira (v8.3.4#803005)