IMPALA-7500: [DOCS] Clarify the workaround for IMPALA-635 Change-Id: I6ce1fab79a8e77c3a9060d1363fc093a261d4e84 Reviewed-on: http://gerrit.cloudera.org:8080/11346 Tested-by: Impala Public Jenkins <[email protected]> Reviewed-by: Alex Rodoni <[email protected]>
Project: http://git-wip-us.apache.org/repos/asf/impala/repo Commit: http://git-wip-us.apache.org/repos/asf/impala/commit/17bfac00 Tree: http://git-wip-us.apache.org/repos/asf/impala/tree/17bfac00 Diff: http://git-wip-us.apache.org/repos/asf/impala/diff/17bfac00 Branch: refs/heads/master Commit: 17bfac00f79219d1cd06be436f6f78b974c6811b Parents: 5474230 Author: Alex Rodoni <[email protected]> Authored: Tue Aug 28 16:01:27 2018 -0700 Committer: Alex Rodoni <[email protected]> Committed: Wed Aug 29 00:11:22 2018 +0000 ---------------------------------------------------------------------- docs/topics/impala_known_issues.xml | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/impala/blob/17bfac00/docs/topics/impala_known_issues.xml ---------------------------------------------------------------------- diff --git a/docs/topics/impala_known_issues.xml b/docs/topics/impala_known_issues.xml index 662132a..b7c439d 100644 --- a/docs/topics/impala_known_issues.xml +++ b/docs/topics/impala_known_issues.xml @@ -617,8 +617,10 @@ ALTER TABLE table_name SET TBLPROPERTIES('EXTERNAL'='TRUE'); <conbody> <p> - Querying certain Avro tables could cause a crash or return no rows, even though Impala - could <codeph>DESCRIBE</codeph> the table. + The default value in Avro schema must match type of first union + type, e.g. if the default value is <codeph>null</codeph>, then the + first type in the <codeph>UNION</codeph> must be + <codeph>"null"</codeph>. </p> <p> @@ -626,14 +628,11 @@ ALTER TABLE table_name SET TBLPROPERTIES('EXTERNAL'='TRUE'); </p> <p> - <b>Workaround:</b> Swap the order of the fields in the schema specification. For - example, <codeph>["null", "string"]</codeph> instead of <codeph>["string", - "null"]</codeph>. - </p> - - <p> - <b>Resolution:</b> Not allowing this syntax agrees with the Avro specification, so it - may still cause an error even when the crashing issue is resolved. + <b>Workaround:</b>Swap the order of the fields in the schema + specification. For example, use <codeph>["null", "string"]</codeph> + instead of <codeph>["string", "null"]</codeph>. Note that the files + written with the problematic schema must be rewritten with the new + schema because Avro files have embedded schemas. </p> </conbody>
