David Wayne Birdsall created TRAFODION-3316:
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Summary: Fix some issues with incremental UPDATE STATISTICS
Key: TRAFODION-3316
URL: https://issues.apache.org/jira/browse/TRAFODION-3316
Project: Apache Trafodion
Issue Type: Improvement
Reporter: David Wayne Birdsall
Assignee: David Wayne Birdsall
Fix some issues with incremental UPDATE STATISTICS.
# The Hive TIMESTAMP datatype has precision 9. When processing a Hive
TIMESTAMP column, UPDATE STATISTICS abends.
# After fixing that, when testing a small example, the sampling ratio for the
sample table is made incorrectly small, resulting in 9207 errors (sample is
empty).
# Sometimes, when populating the sample table, the UPSERT fails because
garbage is used for the table name. This is because the table name is taken
from an NAString that has gone out of scope.
The following test script can be used to test these conditions. In Hive, do the
following:
{quote}create database if not exists h_increUpdatestats;
use h_increUpdatestats;
drop table if exists hive_sequencefile ;
create table hive_sequencefile(C_CUSTKEY int,C_NAME char(20),C_ADDRESS
varchar(20), C_NATIONKEY int, C_TIMESTAMP timestamp,C_PHONE char(20), C_ACCTBAL
string,
C_MKTSEGMENT char(20), C_DATE date) stored as sequencefile;
insert into hive_sequencefile values
(1,'x','xx',1,'2018-08-22 12:00:00.123','xxx','xxxx','xxxxx','2018-08-22'),
(2,'x','xx',2,'2018-08-23 12:00:00.123','xxx','xxxx','xxxxx','2018-08-23'),
(3,'x','xx',3,'2018-08-24 12:00:00.123','xxx','xxxx','xxxxx','2018-08-24'),
(4,'x','xx',4,'2018-08-25 12:00:00.123','xxx','xxxx','xxxxx','2018-08-25'),
(5,'x','xx',5,'2018-08-26 12:00:00.123','xxx','xxxx','xxxxx','2018-08-26');
{quote}
Then in Trafodion do the following:
{quote}update statistics for table hive.h_increUpdatestats.hive_sequencefile
remove sample;
update statistics for table hive.h_increUpdatestats.hive_sequencefile create
sample random 100 percent;
update statistics for table hive.h_increUpdatestats.hive_sequencefile on every
column;
update statistics for table hive.h_increUpdatestats.hive_sequencefile on
existing columns incremental where C_CUSTKEY>=0;
{quote}
Without any fixes, the third UPDATE STATISTICS command abends.
With a fix for the first problem, the last UPDATE STATISTICS command sometimes
fails with error 2109, and always fails with error 9207.
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