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

["Vihang Karajgaonkar (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/IMPALA-8301?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Vihang Karajgaonkar resolved IMPALA-8301.
-----------------------------------------
    Fix Version/s: Impala 4.0
       Resolution: Duplicate

> 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
>          Components: Catalog
>            Reporter: Boris Gitline
>            Priority: Major
>              Labels: catalog-v2
>             Fix For: Impala 4.0
>
>
> 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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