/*
* Find correct PostingItem in non-leaf page. It supposed that page
* correctly chosen and searching value SHOULD be on page
*/
static BlockNumber
dataLocateItem(GinBtree btree, GinBtreeStack *stack)
{
OffsetNumber low,
high,
maxoff;
PostingItem *pitem = NULL;
int result;
Page page = BufferGetPage(stack->buffer);
Assert(!GinPageIsLeaf(page));
Assert(GinPageIsData(page));
if (btree->fullScan)
{
stack->off = FirstOffsetNumber;
stack->predictNumber *= GinPageGetOpaque(page)->maxoff;
return btree->getLeftMostPage(btree, page);
}
low = FirstOffsetNumber;
maxoff = high = GinPageGetOpaque(page)->maxoff;
Assert(high >= low);
high++;
while (high > low)
{
OffsetNumber mid = low + ((high - low) / 2);
pitem = (PostingItem *) GinDataPageGetItem(page, mid);
if (mid == maxoff)
{
/*
* Right infinity, page already correctly chosen with a help of
* dataIsMoveRight
*/
result = -1;
}
else
{
pitem = (PostingItem *) GinDataPageGetItem(page, mid);
result = ginCompareItemPointers(btree->items + btree->curitem, &(pitem->key));
}
if (result == 0)
{
stack->off = mid;
return PostingItemGetBlockNumber(pitem);
}
else if (result > 0)
low = mid + 1;
else
high = mid;
}
Assert(high >= FirstOffsetNumber && high <= maxoff);
stack->off = high;
pitem = (PostingItem *) GinDataPageGetItem(page, high);
return PostingItemGetBlockNumber(pitem);
}
/*
* Try to find parent for current stack position, returns correct
* parent and child's offset in stack->parent.
* Function should never release root page to prevent conflicts
* with vacuum process
*/
void
ginFindParents(GinBtree btree, GinBtreeStack *stack,
BlockNumber rootBlkno)
{
Page page;
Buffer buffer;
BlockNumber blkno,
leftmostBlkno;
OffsetNumber offset;
GinBtreeStack *root = stack->parent;
GinBtreeStack *ptr;
if (!root)
{
/* XLog mode... */
root = (GinBtreeStack *) palloc(sizeof(GinBtreeStack));
root->blkno = rootBlkno;
root->buffer = ReadBuffer(btree->index, rootBlkno);
LockBuffer(root->buffer, GIN_EXCLUSIVE);
root->parent = NULL;
}
else
{
/*
* find root, we should not release root page until update is
* finished!!
*/
while (root->parent)
{
ReleaseBuffer(root->buffer);
root = root->parent;
}
Assert(root->blkno == rootBlkno);
Assert(BufferGetBlockNumber(root->buffer) == rootBlkno);
LockBuffer(root->buffer, GIN_EXCLUSIVE);
}
root->off = InvalidOffsetNumber;
page = BufferGetPage(root->buffer);
Assert(!GinPageIsLeaf(page));
/* check trivial case */
if ((root->off = btree->findChildPtr(btree, page, stack->blkno, InvalidOffsetNumber)) != InvalidOffsetNumber)
{
stack->parent = root;
return;
}
leftmostBlkno = blkno = btree->getLeftMostPage(btree, page);
LockBuffer(root->buffer, GIN_UNLOCK);
Assert(blkno != InvalidBlockNumber);
for (;;)
{
buffer = ReadBuffer(btree->index, blkno);
LockBuffer(buffer, GIN_EXCLUSIVE);
page = BufferGetPage(buffer);
if (GinPageIsLeaf(page))
elog(ERROR, "Lost path");
leftmostBlkno = btree->getLeftMostPage(btree, page);
while ((offset = btree->findChildPtr(btree, page, stack->blkno, InvalidOffsetNumber)) == InvalidOffsetNumber)
{
blkno = GinPageGetOpaque(page)->rightlink;
LockBuffer(buffer, GIN_UNLOCK);
ReleaseBuffer(buffer);
if (blkno == InvalidBlockNumber)
break;
buffer = ReadBuffer(btree->index, blkno);
LockBuffer(buffer, GIN_EXCLUSIVE);
page = BufferGetPage(buffer);
}
if (blkno != InvalidBlockNumber)
{
ptr = (GinBtreeStack *) palloc(sizeof(GinBtreeStack));
ptr->blkno = blkno;
ptr->buffer = buffer;
ptr->parent = root; /* it's may be wrong, but in next call we will
* correct */
ptr->off = offset;
stack->parent = ptr;
return;
}
blkno = leftmostBlkno;
}
}
/*
* Find correct tuple in non-leaf page. It supposed that
* page correctly choosen and searching value SHOULD be on page
*/
static BlockNumber
entryLocateEntry(GinBtree btree, GinBtreeStack *stack)
{
OffsetNumber low,
high,
maxoff;
IndexTuple itup = NULL;
int result;
Page page = BufferGetPage(stack->buffer);
Assert(!GinPageIsLeaf(page));
Assert(!GinPageIsData(page));
if (btree->fullScan)
{
stack->off = FirstOffsetNumber;
stack->predictNumber *= PageGetMaxOffsetNumber(page);
return btree->getLeftMostPage(btree, page);
}
low = FirstOffsetNumber;
maxoff = high = PageGetMaxOffsetNumber(page);
Assert(high >= low);
high++;
while (high > low)
{
OffsetNumber mid = low + ((high - low) / 2);
if (mid == maxoff && GinPageRightMost(page))
/* Right infinity */
result = -1;
else
{
itup = (IndexTuple) PageGetItem(page, PageGetItemId(page, mid));
result = compareAttEntries(btree->ginstate,
btree->entryAttnum, btree->entryValue,
gintuple_get_attrnum(btree->ginstate, itup),
gin_index_getattr(btree->ginstate, itup));
}
if (result == 0)
{
stack->off = mid;
Assert(GinItemPointerGetBlockNumber(&(itup)->t_tid) != GIN_ROOT_BLKNO);
return GinItemPointerGetBlockNumber(&(itup)->t_tid);
}
else if (result > 0)
low = mid + 1;
else
high = mid;
}
Assert(high >= FirstOffsetNumber && high <= maxoff);
stack->off = high;
itup = (IndexTuple) PageGetItem(page, PageGetItemId(page, high));
Assert(GinItemPointerGetBlockNumber(&(itup)->t_tid) != GIN_ROOT_BLKNO);
return GinItemPointerGetBlockNumber(&(itup)->t_tid);
}
