Bug in TZSQLMetadata resultset caching

[ga301]

Hi,

I think I may have tracked down the cause for the problem I reported in http://zeoslib.sourceforge.net/viewtopi ... 40&t=73973:
It seems that the metadata TZVirtualResultset which has been cached for some combination of tablename and property will be closed, when TZSQLMetadata.Close is called. So, if I want to use TZSQLMetadata to get some info for a table and at a later time I want to get the same info again, this will not work, because the cached resultset has been cleared.
There is actually a guard (property DoNotCloseResultset) which could be used to prevent this in the special case where a resultset is cached.

So I tried the following and it seems to work:

1. In ZAbstractRODataset.pas modify the property declaration of DoNotCloseResultset (make it writable):

Code: Select all

property DoNotCloseResultset: Boolean read FDoNotCloseResultset write FDoNotCloseResultset;

2. In ZSqlMetadata.pas, override the InternalClose method:

Code: Select all

TZSQLMetadata = class(TZAbstractRODataset)
protected
...
    procedure InternalClose; override;
...

Code: Select all

procedure TZSQLMetadata.InternalClose;
begin
  DoNotCloseResultSet := true;
  inherited;
end;

I have not yet checked if this introduces any memory leaks or affects other components, but I do not think that it should.

Can somebody please approve and include this fix (or anything else that targets this problem)?
Thank you very much.

Best regards
Gunnar

[marsupilami]

Hello Gunnar,

Egonhugeist told me that the problem should be fixed in the Zeos 7.2 branch by now as well. Could you please try that?
With best regards,

Jan

[volkerp]

Hello,

in 7.2.4 stable this problem persists
you can simple test it with the ZControlsExample example.

[marsupilami]

Hello Volker,

we didn't create a new release of Zeos 7.4 yet. If you need this bug fixed, you might want to download a snapshot from our SVN:
https://sourceforge.net/p/zeoslib/code- ... 2-patches/

We currently plan to release Zeos 7.2.6 in the upcoming weeks. Then this bug will be fixed in a release version.

Best regards,

Jan