[jira] [Commented] (TRAFODION-3137) speed up count(*) by read row count from stats in special use cases

["Anoop Sharma (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/TRAFODION-3137?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16540622#comment-16540622 ] 

Anoop Sharma commented on TRAFODION-3137:
-----------------------------------------

Does update stats always keeps the exact count or can it be approx at times?

How will it be determined that a table has not been updated (ins/upd/del) after upd stats was done and before count(*) is executed? Will that check happen at every execute of a count?

Is this a special row count statement or the regular count(*) stmt?

Can a select from histogram table joined with MD objects table be used to get the count? 

> speed up count(*) by read row count from stats in special use cases
> -------------------------------------------------------------------
>
>                 Key: TRAFODION-3137
>                 URL: https://issues.apache.org/jira/browse/TRAFODION-3137
>             Project: Apache Trafodion
>          Issue Type: Improvement
>            Reporter: liu ming
>            Assignee: liu ming
>            Priority: Major
>
> If the table is bulkload once and no change, and finish update statistics.
> When doing count(*), there is no need to scan the whole table, but to read row count from stats



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