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https://issues.apache.org/jira/browse/DERBY-6978?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Christian Lutz updated DERBY-6978:
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Attachment: (was: 20172711_derbydb_bugreport.7z)
> Select for ID does not deliver existing Row
> -------------------------------------------
>
> Key: DERBY-6978
> URL: https://issues.apache.org/jira/browse/DERBY-6978
> Project: Derby
> Issue Type: Bug
> Reporter: Christian Lutz
> Attachments: 20173011_derbydb_bugreport.zip
>
>
> Hello everybody,
> we are currently facing a rather strange problem, using the Derby-DB.
> In the attached Database there is one table left, called 'TreeEntry' and for
> several kinds of querries performed on it Derby claims something different
> than is actually true.
> For example the statement
> {code}
> select count(*) from treeentry;
> {code}
> tells, that there would be 1426 lines in the table, but if I select all rows
> and copy them into an editor I see, that there are actually 1492 lines.
> Furthermore, the following statement actually returns data, which, in my
> understanding, should never be the case:
> {code}
> select * from treeentry t where id not in (select id from treeentry where id
> = t.id);
> {code}
> But on the other hand
> {code}
> select count(*) from treeentry t where id not in (select id from treeentry
> where id = t.id);
> {code}
> tells, that there would be zero such rows.
> In the result of the beforementioned select I see, that a line exists, that
> has the ID 111664.
> If I then explicitly select for this row (which I've just seen existing in
> the previous select) via
> {code}
> select * from treeentry where id = 111664;
> {code}
> nothing is returned.
> I tried updating the statistics for this table via
> {code}
> CALL SYSCS_UTIL.SYSCS_UPDATE_STATISTICS('APP', 'TREEENTRY', null)
> {code}
> but this call does not terminate.
> But here I have to remark, that there were also several other tables in the
> database with the same phenomenon existing, where this call actually
> terminated, even though it didn't change anything about the problem.
> The derby version, with which this problem appeared was 10.12.1.1
> But unfortunately, I have absolutely no idea of how to reproduce it.
> The only thing I probably can say, that has been done before this issue
> appeared, was, that the database was copied from one system to another. I
> don't expect any kinds of incompatibilities there, as, after we discovered
> this issue, we did the same with a backup of the database in the same way and
> the issue did not reappear.
> I would be very happy, if someone could give me some kind of hint about
> whether this is a known and already fixed problem, what we could maybe do to
> avoid this in the future or similar.
> User and Password for the attached Database are btw APP/APP.
> If you need any further information from me I'm glad to deliver this still.
> Thank you already for your help.
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