[jira] [Created] (TRAFODION-277) LP Bug: 1320387 - Update statistics spawned a large number of tdm_arkcmps and never finished

["Alice Chen (JIRA)" <ji...@apache.org>]

Alice Chen created TRAFODION-277:
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             Summary: LP Bug: 1320387 - Update statistics spawned a large number of tdm_arkcmps and never finished
                 Key: TRAFODION-277
                 URL: https://issues.apache.org/jira/browse/TRAFODION-277
             Project: Apache Trafodion
          Issue Type: Bug
          Components: sql-cmp
            Reporter: Weishiun Tsai
            Assignee: Qifan Chen
            Priority: Blocker


The following 3 statements hanged at the update statistics statement.  The table only has 3 rows.  After about 30 minutes, the update statistics statement spawned about 99 tdm_arkcmp processes on centos-mapr1, a 6-node cluster.  The statement never finished before it was killed.

This was seen on the datalake v40535 build.

Here are the statements to reproduce this problem.

create table t (a int, b int, c int);
insert into t values (1,1,1),(2,2,2),(3,3,3);
update statistics for table t on a generate 100 intervals;

Here are the execution of the statements and snapshots of the tdm_arkcmp processes at each point.   There were 2 tdm_arkcmp processes before update statistics statement was issued.  30 minutes after the statement was issued, the total number was 99 before the statement was killed. 

[trafodion@centos-mapr1 scripts]$ sqps | grep tdm_arkcmp | wc -l
0

>>create table t (a int, b int, c int);

[trafodion@centos-mapr1 scripts]$ sqps | grep tdm_arkcmp | wc -l
1

>>insert into t values (1,1,1),(2,2,2),(3,3,3);

[trafodion@centos-mapr1 scripts]$ sqps | grep tdm_arkcmp | wc -l
2

>>update statistics for table t on a generate 100 intervals;

[trafodion@centos-mapr1 scripts]$ sqps | grep tdm_arkcmp | wc -l
99



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