[jira] [Created] (IMPALA-8301) Eliminate need for SYNC_DDL in local catalog mode

["Boris Gitline (JIRA)" <ji...@apache.org>]

Boris Gitline created IMPALA-8301:
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             Summary: Eliminate need for SYNC_DDL in local catalog mode
                 Key: IMPALA-8301
                 URL: https://issues.apache.org/jira/browse/IMPALA-8301
             Project: IMPALA
          Issue Type: Improvement
            Reporter: Boris Gitline


In the following scenario looks like the INSERT on coordinator 2 is gated behind a long-running DDL on coordinator 1. That scenario still requires SYNC_DDL even in metadata v2. We want to change the metadata handling design so that coordinator 3 does not have to wait for the long-running DDL to complete – it would render the correct result on the target table t1 reference.

Step1. coordinator 1
##*say*, the following compute stats runs about 100 seconds
compute stats tao_ddl_contention;

[steps 2 and 3 are performed while COMPUTE STATS is running]

Step2. coordinator 2
create another new table.

create table t1(c1 int);

insert into t1 select 1 ;

select * from t1;
 [can see the inserted rows]

Step3. coordinator 3
query the newly inserted rows in t1 while the COMPUTE STATS is still running:

select * from t1;
 [see no rows]

##the query in [Step3] won't show the row inserted by step2 until the first step "compute stats" completed, unless:


- SYNC_DDL is set before the INSERT on coordinator 2, or
 * when the step1 compute stats is completed, or
 * you can see the data from this impala session, or
 * a manual refresh of the t1 table.



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