Need some help on code

Hi,

I was trying to change to cluster command to do the its writes clustered
by a 100 tuples, thus hoping to improve performance. However, the code
I've written crashes. This has certainly to do with some internal states
of pgsql that aren't preserved in a HeapTuple.

Could somebody with knowledge have a brief glimpse on my code and perhaps
tell me how to do it properly?

Maarten

_____________________________________________________________________________
| TU Delft, The Netherlands, Faculty of Information Technology and Systems |
| Department of Electrical Engineering |
| Computer Architecture and Digital Technique section |
| M(dot)Boekhold(at)et(dot)tudelft(dot)nl |
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static void
rebuildheap(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex)
{
Relation LocalNewHeap,
LocalOldHeap,
LocalOldIndex;
IndexScanDesc ScanDesc;
RetrieveIndexResult ScanResult;
ItemPointer HeapTid;
HeapTuple LocalHeapTuple;
Buffer LocalBuffer[100];
Oid OIDNewHeapInsert;
Dllist *ScanResList;
Dlelem *ListEl;
int count, loop;

/*
* Open the relations I need. Scan through the OldHeap on the OldIndex
* and insert each tuple into the NewHeap.
*/
LocalNewHeap = (Relation) heap_open(OIDNewHeap);
LocalOldHeap = (Relation) heap_open(OIDOldHeap);
LocalOldIndex = (Relation) index_open(OIDOldIndex);
ScanResList = DLNewList();

ScanDesc = index_beginscan(LocalOldIndex, false, 0, (ScanKey) NULL);

loop = 1;
while (loop) {
count = 0;
while ((count < 100) &&
((ScanResult =
index_getnext(ScanDesc,
ForwardScanDirection)) != NULL))
{

HeapTid = &ScanResult->heap_iptr;
pfree(ScanResult);
LocalHeapTuple = heap_fetch(LocalOldHeap, false,
HeapTid, &LocalBuffer[count]);
ListEl = DLNewElem(LocalHeapTuple);
DLAddTail(ScanResList, ListEl);
count++;
}

if (count < 100) loop = 0;

count = 0;
while ((ListEl = DLRemHead(ScanResList)) != NULL) {
LocalHeapTuple = (HeapTuple)ListEl->dle_val;
DLFreeElem(ListEl);
OIDNewHeapInsert =
heap_insert(LocalNewHeap, LocalHeapTuple);
ReleaseBuffer(LocalBuffer[count]);
count++;
}
}

index_endscan(ScanDesc);

index_close(LocalOldIndex);
heap_close(LocalOldHeap);
heap_close(LocalNewHeap);
DLFreeList(ScanResList);
}