Vuk Ercegovac has posted comments on this change. ( 
http://gerrit.cloudera.org:8080/11608 )

Change subject: IMPALA-7597: wraps retries around CatalogMetaProvider
......................................................................


Patch Set 2:

(3 comments)

http://gerrit.cloudera.org:8080/#/c/11608/2//COMMIT_MSG
Commit Message:

http://gerrit.cloudera.org:8080/#/c/11608/2//COMMIT_MSG@18
PS2, Line 18: methods of CatalogMetaProvider with retries/logging. When 
obtaining
> I'm confused how this is supposed to work. Don't we need to retry from the
good point. most of the top-level "describe" methods use strings as args, not 
refs. the refs are mostly used for everything under createExecRequest, and 
there, we're guarding at the top-level. the method to get column stats and the 
one that looks up all partition info should change as a result. will confirm 
with tests.


http://gerrit.cloudera.org:8080/#/c/11608/1/fe/src/main/java/org/apache/impala/catalog/local/RetryableMetaProvider.java
File 
fe/src/main/java/org/apache/impala/catalog/local/RetryableMetaProvider.java:

http://gerrit.cloudera.org:8080/#/c/11608/1/fe/src/main/java/org/apache/impala/catalog/local/RetryableMetaProvider.java@126
PS1, Line 126: while (true) {
             :       try {
             :         return provider_.loadTableNames(dbName);
             :       } catch (InconsistentMetadataFetchException e) {
             :         tracker.handleRetryOrThrow(e);
             :       }
> can we factor out while(true) try {} catch {retry} into a helper?  I think
will try it but only after we're settled on this approach.


http://gerrit.cloudera.org:8080/#/c/11608/1/fe/src/main/java/org/apache/impala/service/Frontend.java
File fe/src/main/java/org/apache/impala/service/Frontend.java:

http://gerrit.cloudera.org:8080/#/c/11608/1/fe/src/main/java/org/apache/impala/service/Frontend.java@834
PS1, Line 834: ribeResult
> It looks like the callers should now understand whether an operation should
As discussed, I was trading off looping too many times with retry (consider 
getCatalogMetrics and all query paths under createExecRequest) vs. letting one 
of these inconsistent metadata exceptions loose. We spend far more cycles in 
the latter so opted to not go with an approach that changes the default to loop.



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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: I43a21571d54a7966c5c68bea1fe69dbc62be2a0b
Gerrit-Change-Number: 11608
Gerrit-PatchSet: 2
Gerrit-Owner: Vuk Ercegovac <[email protected]>
Gerrit-Reviewer: Bharath Vissapragada <[email protected]>
Gerrit-Reviewer: Impala Public Jenkins <[email protected]>
Gerrit-Reviewer: Tianyi Wang <[email protected]>
Gerrit-Reviewer: Todd Lipcon <[email protected]>
Gerrit-Reviewer: Vuk Ercegovac <[email protected]>
Gerrit-Comment-Date: Tue, 09 Oct 2018 20:48:56 +0000
Gerrit-HasComments: Yes

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