[jira] [Commented] (HAWQ-273) Concurrent read committed SELECT return 0 rows for AO table which is ALTERed with REORGANIZE by other transaction

[ASF GitHub Bot (JIRA)]

    [ 
https://issues.apache.org/jira/browse/HAWQ-273?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15070719#comment-15070719
 ] 

ASF GitHub Bot commented on HAWQ-273:
-------------------------------------

Github user liming01 commented on a diff in the pull request:

    https://github.com/apache/incubator-hawq/pull/211#discussion_r48400788
  
    --- Diff: src/backend/tcop/postgres.c ---
    @@ -1645,7 +1645,7 @@ exec_simple_query(const char *query_string, const 
char *seqServerHost, int seqSe
                querytree_list = pg_analyze_and_rewrite(parsetree, query_string,
                                                                                
                NULL, 0);
     
    -           plantree_list = pg_plan_queries(querytree_list, NULL, false, 
QRL_ONCE);
    +           plantree_list = pg_plan_queries(querytree_list, NULL, true, 
QRL_ONCE);
     
    --- End diff --
    
    The comment is confusing, it just describes the details about 
implementation of this function, instead of describing the API parameter 
constraint. The logic of skipping snapshot for the utility statements is inside 
pg_plan_queries(). So it is no problem. 


> Concurrent read committed SELECT return 0 rows for AO table which is ALTERed 
> with REORGANIZE by other transaction
> -----------------------------------------------------------------------------------------------------------------
>
>                 Key: HAWQ-273
>                 URL: https://issues.apache.org/jira/browse/HAWQ-273
>             Project: Apache HAWQ
>          Issue Type: Bug
>          Components: Transaction
>            Reporter: Ming LI
>            Assignee: Ming LI
>
> testdb=# DROP TABLE tbl_isolation;
> DROP TABLE
> testdb=# CREATE TABLE tbl_isolation (a INT, b int, c int) WITH 
> (appendonly=true);
> CREATE TABLE
> testdb=# INSERT INTO tbl_isolation SELECT generate_series(1, 100000), 
> generate_series(1, 100000), generate_series(1, 100000);
> INSERT 0 100000
> •
> Thread A:
> testdb=# BEGIN transaction isolation level SERIALIZABLE;
> BEGIN
> testdb=# ALTER TABLE tbl_isolation set with ( reorganize='true') distributed 
> randomly;
> ALTER TABLE
> •
> Thread B:
> testdb=# BEGIN transaction isolation level read committed;
> BEGIN
> testdb=# select count(*) from tbl_isolation;
> •
> Thread A:
> testdb=# commit;
> COMMIT
> •
> •
> Thread B:
> testdb=# select count(*) from tbl_isolation;
> count
> -------
> 0
> (1 row)



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