Exponential growth of the slots table

[John Ralls]

On Dec 3, 2010, at 10:42 PM, Phil Longstaff wrote:

> The slots table contains extra information for the other objects.  This extra 
> information allows extra values to be tied onto objects.  It will be loaded and 
> saved with the objects.  When loaded, the slots are like a directory structure.  
> At each level, there are named keys with values of different types (int, string, 
> date, ...).  There can also be sub-levels.
> 
> The main key is the guid field which contains the guid of the object that this 
> slot belongs to.  This object can be of any other type (account, split, 
> transaction, book, ...).  The other fields in the slot table are the full 
> directory path of the key, the value type, and the value.
> 
> I believe that guid/path should be unique.

That's only part of the story: Using full paths (not really directory paths, more like xml XPaths except that the components are the the string values of the slots:key elements rather than element names... which is the source of Bug 635859 [1], because the the delimiter character '/' is allowed in string data (though not in element names). didn't work for hierarchies of slots, which are used in several places (Bug 627831 [2]): Child elements were silently not created during load. r19729 added recursion to the slot storage so that each level is stored as a row, and slots with children (either of type frame or type list) get a guid_val created on the fly -- which is discarded on load to provide for exact round-tripping to xml -- which is used as the obj_guid to link children to their parents. 

But that isn't the problem: The problem is that save_slots doesn't query to see if a slot record exists before inserting it -- and the slot table's primary key is an autoincrement, so there isn't a key conflict, either.

I've created bug 636459 [3] to hang a change on. Further discussion should go there.

Regards,
John Ralls







[1] https://bugzilla.gnome.org/show_bug.cgi?id=635859
[2] https://bugzilla.gnome.org/show_bug.cgi?id=627831
[3] https://bugzilla.gnome.org/show_bug.cgi?id=636459