Subform with OLE field very slow inside parent form

[harmankardon]

Hello all,



I have a form called frmMain which is bound to a table called tblMaster. I also have a subform called frmSubForm which is bound to an BLOB attachments table called tblBlob and linked to frmMain by the primary key in tblMaster.

My problem is that when opening the subform (in continuous view like it is on the main form) on its own, it works fantastic. I can scroll down through all the attachments and open attachments with no performance issues whatsoever. But when I open the main form and the subform is displayed as a subform control, performance is extremely poor with attachments over a few MB. Any record that has attachments over 2-3 MB will take up to 15 seconds to load. Also, the attachments subform control is in the middle of my main form (which is a long form in Single Form view) and every time I scroll down the main form, the whole thing freezes for about 15 seconds as soon as the attachments subform control appears at the bottom of the screen. Once the subform control is on the screen, there are no major performance issues.

If I scroll back up again and then back down, same thing, big freeze. Closing the form takes 5-10 seconds and editing any of the fields in the subform is slow to respond.

Now the tricky part is that the main form loads in under 2 seconds with no attachments, and the subform form will load on its own almost instantly, even though it displays all ~70 attachments on one screen.

If I set the subform's Recordset Type to snapshot, the main form works beautifully (just as the subform works on its own in dynaset) but I can't update the recordset.

Any idea why both forms perform so well on their own and the subform can display ~70 BLOB records with no problems at all, but when opened inside the parent form, it causes huge performance drops?

[harmankardon]

Also, if I set the visible property of the subform control to false, the main form still takes 10-15 seconds to load but once loaded, I can scroll without any "rendering" slow downs. I am really scratching my head on this one.