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https://issues.apache.org/jira/browse/CALCITE-5443?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17650006#comment-17650006
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Julian Hyde edited comment on CALCITE-5443 at 12/20/22 10:18 PM:
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I agree that this is a bug, but it took me a while to understand, because
multiple results is a JDBC behavior that not many people use. I initially
thought you were talking about {{ResultSet.next()}}.
For the benefit of people not familiar with JDBC, in your description could you
explain the purpose of {{getMoreResults}}, the lifecycle of update count, and
why {{getMoreResults}} would change the update count?
Your current summary describes the fix, not the problem. I think the following
would be a better summary: "After Statement.getMoreResults() has returned
false, Statement.getUpdateCount() should return -1"
Does this problem apply to both {{getMoreResults()}} and
{{getMoreResults(int)}}?
was (Author: julianhyde):
Javadoc says
{quote}
Retrieves the current result as an update count; if the result is a ResultSet
object or there are no more results, -1 is returned. This method should be
called only once per result.
{quote}
The way I read that, if my statement is a query, {{getUpdateCount}} should
always return -1 because a query returns a {{ResultSet}}.
> Reset update count when checking for more results
> -------------------------------------------------
>
> Key: CALCITE-5443
> URL: https://issues.apache.org/jira/browse/CALCITE-5443
> Project: Calcite
> Issue Type: Bug
> Components: avatica
> Reporter: Gregory Hart
> Assignee: Gregory Hart
> Priority: Major
> Time Spent: 10m
> Remaining Estimate: 0h
>
> The JavaDoc for {{java.sql.Statement#getMoreResults(int)}} says there are no
> more results when the following is true:
>
> {code:java}
> // stmt is a Statement object ((stmt.getMoreResults(current) == false) &&
> (stmt.getUpdateCount() == -1)) {code}
> In {{{}AvaticaStatement{}}}, {{getMoreResults(int)}} always returns {{false}}
> but does not reset the {{{}updateCount{}}}. This could result in an infinite
> loop in the JDBC client because the return value is indicating there are
> additional results when there are actually none.
>
> *Steps to reproduce:*
> # Execute an INSERT query by calling Statement#execute(String). Verify that
> the return value is false indicating it is an update count.
> # Call Statement#getMoreResults(). Verify that the return value is false
> indicating it is an update count or there are no more results.
> # Call Statement#getUpdateCount().
> *Expected results:*
> The call to getUpdateCount() returns -1 indicating there are no more results.
> *Actual results:*
> The call to getUpdateCount() returns the update count for the INSERT query,
> which should only have one result.
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