Vihang Karajgaonkar has posted comments on this change. ( 
http://gerrit.cloudera.org:8080/17253 )

Change subject: IMPALA-6671: Change wait for sync ddl timeout
......................................................................


Patch Set 4:

(3 comments)

http://gerrit.cloudera.org:8080/#/c/17253/4/be/src/catalog/catalog-server.cc
File be/src/catalog/catalog-server.cc:

http://gerrit.cloudera.org:8080/#/c/17253/4/be/src/catalog/catalog-server.cc@92
PS4, Line 92: DEFINE_int32(max_wait_time_for_sync_ddl_s, 0, "Maximum time (in 
seconds) until "
> Do you have a recommendation on what this should be when topic_update_tbl_m
Do you mean what should the recommendation for the least value of it? It is 
hard to predict. Ideally, the minimum time required for this would be the 
2*(time required for one topic update delta calculation).

The default value of 0 is good for most cases when 
topic_update_tbl_max_wait_time_ms is enabled, unless there are any issues and 
user has to override it manually.


http://gerrit.cloudera.org:8080/#/c/17253/4/be/src/catalog/catalog-server.cc@94
PS4, Line 94: will
> nit: will wait?
Done


http://gerrit.cloudera.org:8080/#/c/17253/4/fe/src/main/java/org/apache/impala/catalog/CatalogServiceCatalog.java
File fe/src/main/java/org/apache/impala/catalog/CatalogServiceCatalog.java:

http://gerrit.cloudera.org:8080/#/c/17253/4/fe/src/main/java/org/apache/impala/catalog/CatalogServiceCatalog.java@3094
PS4, Line 3094:     long maxNumAttempts = 5;
> I think another solution is increasing maxNumAttempts with maxSkippedUpdate
Unfortunately, I don't think this approach would work. 
maxSkippedUpdatesLockContention_ is not just simply counts the number of topic 
updates due to the lock, but number of distinct lock operations which are 
skipped by topic update thread. Otherwise, it would be not work since we would 
just be delaying the onset of the problem. Hence we cannot rely on 
maxSkippedUpdatesLockContention_ since the topic updates skipped will almost 
always be much higher than maxSkippedUpdatesLockContention_. Hope that makes 
sense.



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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: I79e64cdec0e6aa7b597a47851b4b5c5441ca5528
Gerrit-Change-Number: 17253
Gerrit-PatchSet: 4
Gerrit-Owner: Vihang Karajgaonkar <[email protected]>
Gerrit-Reviewer: Impala Public Jenkins <[email protected]>
Gerrit-Reviewer: Quanlong Huang <[email protected]>
Gerrit-Reviewer: Vihang Karajgaonkar <[email protected]>
Gerrit-Comment-Date: Mon, 05 Apr 2021 20:59:55 +0000
Gerrit-HasComments: Yes

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