Re: [Firebird-odbc-devel] Driver issues

[Martijn T. <m.t...@up...>]

Hello Alexander,

>> I've tried a different componentset and it browses data just
>> fine in Delphi.
>>
>> However, I ran into a new problem --
>>
>> I have this table with BLOBs, I put down an odbc query
>> component in Delphi and set "UniDirectional" to True.
>>
>> When I want to activate the query component, it calls
>> SQLExecute and then doesn't return for quite a while.
>> Meanwhile, the memory usage of the application goes
>> -way up- ... and it ends with an Access Violation error.
>>
>> Is the driver fetching all rows despite the component
>> not doing that?
>>
>>
>>
> Hello Martijn!
> What components do you use?

The ones from SoftVector.

> I think you need the Cursor type  = ForwardOnly (else the driver
> fetching all rows) .

It seems the components always used a static cursor. I've modified
the components to use a ForwardOnly cursor:

  if FUniDirectional
  then CheckError(SQLSetStmtAttr(FStmtHandle, SQL_ATTR_CURSOR_TYPE, 
Pointer(SQL_CURSOR_FORWARD_ONLY), SQL_IS_UINTEGER))
  // set static cursor to avoid problems with blobs
  else CheckError(SQLSetStmtAttr(FStmtHandle, SQL_ATTR_CURSOR_TYPE, 
Pointer(SQL_CURSOR_STATIC), SQL_IS_UINTEGER));


It returns from SQLExecute instantly now, so that's good.

But when going through all rows, it still takes a lot of memory, as
if all blobs are instantiated in memory. What could cause this?

With regards,

Martijn Tonies
Upscene Productions
http://www.upscene.com

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