BloomTuple*
BloomFormTuple(BloomState *state, ItemPointer iptr, Datum *values, bool *isnull)
{
int i;
BloomTuple *res = palloc0(state->sizeOfBloomTuple);
res->heapPtr = *iptr;
/*
* Blooming
*/
for(i=0; i<state->nColumns; i++)
{
/*
* skip nulls
*/
if ( isnull[i] )
continue;
signValue(state, res->sign, values[i], i);
}
return res;
}
/*
* Insert all matching tuples into to a bitmap.
*/
int64
blgetbitmap(IndexScanDesc scan, TIDBitmap *tbm)
{
int64 ntids = 0;
BlockNumber blkno = BLOOM_HEAD_BLKNO,
npages;
int i;
BufferAccessStrategy bas;
BloomScanOpaque so = (BloomScanOpaque) scan->opaque;
if (so->sign == NULL)
{
/* New search: have to calculate search signature */
ScanKey skey = scan->keyData;
so->sign = palloc0(sizeof(SignType) * so->state.opts.bloomLength);
for (i = 0; i < scan->numberOfKeys; i++)
{
/*
* Assume bloom-indexable operators to be strict, so nothing could
* be found for NULL key.
*/
if (skey->sk_flags & SK_ISNULL)
{
pfree(so->sign);
so->sign = NULL;
return 0;
}
/* Add next value to the signature */
signValue(&so->state, so->sign, skey->sk_argument,
skey->sk_attno - 1);
skey++;
}
}
/*
* We're going to read the whole index. This is why we use appropriate
* buffer access strategy.
*/
bas = GetAccessStrategy(BAS_BULKREAD);
npages = RelationGetNumberOfBlocks(scan->indexRelation);
for (blkno = BLOOM_HEAD_BLKNO; blkno < npages; blkno++)
{
Buffer buffer;
Page page;
buffer = ReadBufferExtended(scan->indexRelation, MAIN_FORKNUM,
blkno, RBM_NORMAL, bas);
LockBuffer(buffer, BUFFER_LOCK_SHARE);
page = BufferGetPage(buffer);
TestForOldSnapshot(scan->xs_snapshot, scan->indexRelation, page);
if (!BloomPageIsDeleted(page))
{
OffsetNumber offset,
maxOffset = BloomPageGetMaxOffset(page);
for (offset = 1; offset <= maxOffset; offset++)
{
BloomTuple *itup = BloomPageGetTuple(&so->state, page, offset);
bool res = true;
/* Check index signature with scan signature */
for (i = 0; i < so->state.opts.bloomLength; i++)
{
if ((itup->sign[i] & so->sign[i]) != so->sign[i])
{
res = false;
break;
}
}
/* Add matching tuples to bitmap */
if (res)
{
tbm_add_tuples(tbm, &itup->heapPtr, 1, true);
ntids++;
}
}
}
UnlockReleaseBuffer(buffer);
CHECK_FOR_INTERRUPTS();
}
FreeAccessStrategy(bas);
return ntids;
}
